# Surgical-mask recommendation × Transmission to others — Wearer infection and directly unmeasured gaps Verdict 2971 · Evidence Check Stored-material review date: Not recorded Original evidence cut-off: 2026-08-26 Review-criteria version: 1.0 Public page/material preparation date: 2026-10-14 Clinical papers were not read directly; existing review summaries were checked. No new clinical-literature search was performed. Unverified does not mean that research is absent or that there is no effect. ## Assessment scope - Population: 6,024 community adults in 2020 Denmark; wearer denominators are distinguished from unverified direct contact/cluster/network denominators - Ingredient, formulation and route: Surgical-mask recommendation, 50 masks/instructions supplied; distinguished from actual wearing, mandates and source control - Dose: Original research-intervention identification: 50 masks/instructions and one month; no mask/infection-prevention instructions - Comparator: Control group and prevailing public-health advice in both groups; actual masks/contacts, contamination and exposure details remain unverified - Measured outcome: Selected transmission/source control was directly unmeasured; separate from parent wearer infection at one month by antibody/PCR/hospital diagnosis - Duration: One-month wearer follow-up in 2020 Denmark; direct contact/cluster/transmission-timing/observation materials are absent - Questions outside this scope: Transferring wearer outcomes to transmission/source control or recommendations to full-wearing/mandate effects; Combining outcomes in different populations as the same effect; Summing the same report/people/tests/groups/events/timepoints/bibliographies and sibling sheets as new independent trials/participants; New effects/CI/invented quantities, equivalence/zero effects, reassessment/grades or independence certification from original numbers; Mask/infection-prevention/treatment-replacement instructions ## Checklist items ### N01 · Which existing transmission-to-others claim is being transferred? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: The selected claim is reduced transmission to other people, with original subclaim grade ? and the note that this was not measured by the trial. Absent subclaim score/status/axes are separated from parent D34 and axes. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Direct transmission population/endpoints, contact/cluster denominators, comparison/period and existing boundary review. Parent scores are not filled into the subclaim. - Required materials and conditions: Selected wording/subclaim grade versus parent wearer results - Materials to obtain first: Direct transmission population/endpoints, contact/cluster denominators, comparison/period and existing boundary review. Parent scores are not filled into the subclaim. - Further research: Materials needed: Direct transmission population/endpoints, contact/cluster denominators, comparison/period and existing boundary review. Parent scores are not filled into the subclaim. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for selected wording/subclaim grade versus parent wearer results together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect selected wording/subclaim grade versus parent wearer results with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N02 · Are wearer protection and source control directly distinguished? Verification status: Unverified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Existing Korean/English reader answers explicitly state that transmission/source control and mandates were not tested. Null wearer infection is not transferred to zero/null or positive transmission effects. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Infection sources/contacts, transmission direction/ascertainment, direct cluster/network/contact tracing, denominators/effects/CI. Unmeasured is not changed to zero transmission events. - Required materials and conditions: Infection acquired by the wearer versus transmission to others - Materials to obtain first: Infection sources/contacts, transmission direction/ascertainment, direct cluster/network/contact tracing, denominators/effects/CI. Unmeasured is not changed to zero transmission events. - Further research: Materials needed: Infection sources/contacts, transmission direction/ascertainment, direct cluster/network/contact tracing, denominators/effects/CI. Unmeasured is not changed to zero transmission events. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for infection acquired by the wearer versus transmission to others together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect infection acquired by the wearer versus transmission to others with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N03 · Was the intervention enforced or verified actual wearing? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: The original intervention recommended masks to community adults and supplied 50 surgical masks/instructions. This differs from full actual wearing, mandates or effects of all mask types. Research intervention identification does not provide use/infection-prevention instructions. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Original recommendation/distribution, actual use/adherence, product identity/masks and concurrent exposure. No new wearer-adherence or transmission effects are calculated. - Required materials and conditions: Surgical-mask recommendation, 50 masks and instructions - Materials to obtain first: Original recommendation/distribution, actual use/adherence, product identity/masks and concurrent exposure. No new wearer-adherence or transmission effects are calculated. - Further research: Materials needed: Original recommendation/distribution, actual use/adherence, product identity/masks and concurrent exposure. No new wearer-adherence or transmission effects are calculated. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for surgical-mask recommendation, 50 masks and instructions together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect surgical-mask recommendation, 50 masks and instructions with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N04 · What were the control and prevailing advice in both groups? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Original materials record 3,030 assigned to recommendations, 2,994 to control, with both groups following prevailing advice. Actual control mask use/contact/behavior/exposure details remain unverified. This is not relabeled as comparison with no preventive exposure. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Actual group masks/contacts/public-health exposure, contamination, expectations/behavior and adherence. Contributions beyond recommendation differences are not newly established. - Required materials and conditions: Recommendation versus control and common public-health advice - Materials to obtain first: Actual group masks/contacts/public-health exposure, contamination, expectations/behavior and adherence. Contributions beyond recommendation differences are not newly established. - Further research: Materials needed: Actual group masks/contacts/public-health exposure, contamination, expectations/behavior and adherence. Contributions beyond recommendation differences are not newly established. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for recommendation versus control and common public-health advice together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect recommendation versus control and common public-health advice with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N05 · Which period, setting and population were studied? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: The original trial involved community adults in 2020 Denmark, where mask use was uncommon. It is not extended to healthcare, other variants/epidemics, mandates or other populations. Eligibility/infection history/baseline/exposure details remain unverified. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Direct transmission materials with eligibility, location/period/epidemic, baseline/contact/concurrent exposure. This is not converted to current mask/infection-prevention guidance. - Required materials and conditions: 2020 Danish community and uncommon mask use - Materials to obtain first: Direct transmission materials with eligibility, location/period/epidemic, baseline/contact/concurrent exposure. This is not converted to current mask/infection-prevention guidance. - Further research: Materials needed: Direct transmission materials with eligibility, location/period/epidemic, baseline/contact/concurrent exposure. This is not converted to current mask/infection-prevention guidance. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for 2020 Danish community and uncommon mask use together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect 2020 Danish community and uncommon mask use with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N06 · Was one-month follow-up long-term observation of transmission networks? Verification status: Unverified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Original follow-up was one month. Direct contact/cluster, infection-source/secondary-transmission timing/observation materials are absent. Wearer duration does not fill valid transmission follow-up or long-term effects. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Direct infection-source/contact enrollment, exposure/incubation/follow-up/testing, time denominators and losses. No new time/day calculations. - Required materials and conditions: One-month wearer follow-up versus contact observation - Materials to obtain first: Direct infection-source/contact enrollment, exposure/incubation/follow-up/testing, time denominators and losses. No new time/day calculations. - Further research: Materials needed: Direct infection-source/contact enrollment, exposure/incubation/follow-up/testing, time denominators and losses. No new time/day calculations. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for one-month wearer follow-up versus contact observation together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect one-month wearer follow-up versus contact observation with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N07 · Are allocation, complete-case analysis and missingness separated? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Preserve 6,024 allocated (3,030/2,994), 4,862 primary complete cases (2,392/2,470) and 19.3% missingness. Allocation/observation/analysis and other-person/contact denominators differ. No new dropout counts/group missingness rates. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Flow, group completion/missingness/testing, reasons/handling/sensitivity and contact denominators. Complete-case results do not certify ITT for everyone or outcomes in others. - Required materials and conditions: 6,024, 4,862 and 19.3% - Materials to obtain first: Flow, group completion/missingness/testing, reasons/handling/sensitivity and contact denominators. Complete-case results do not certify ITT for everyone or outcomes in others. - Further research: Materials needed: Flow, group completion/missingness/testing, reasons/handling/sensitivity and contact denominators. Complete-case results do not certify ITT for everyone or outcomes in others. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for 6,024, 4,862 and 19.3% together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect 6,024, 4,862 and 19.3% with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N08 · What ascertainment methods define wearer infection? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: The original endpoint is the wearer’s own one-month SARS-CoV-2 infection by antibody testing, PCR or hospital diagnosis. It is not substituted with PCR alone, test counts, repeated events in the same person or confirmed transmission to others. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Original ascertainment/event definitions, test selection/omissions, baseline/repetition, denominators and infection-source linkage. Endpoint components are not summed as new infections/participants. - Required materials and conditions: One-month infection by antibody testing, PCR or hospital diagnosis - Materials to obtain first: Original ascertainment/event definitions, test selection/omissions, baseline/repetition, denominators and infection-source linkage. Endpoint components are not summed as new infections/participants. - Further research: Materials needed: Original ascertainment/event definitions, test selection/omissions, baseline/repetition, denominators and infection-source linkage. Endpoint components are not summed as new infections/participants. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for one-month infection by antibody testing, PCR or hospital diagnosis together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect one-month infection by antibody testing, PCR or hospital diagnosis with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N09 · Which outcome do the wearer effects/CI describe? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Original primary results: 42/2,392(1.8%) versus 53/2,470(2.1%); absolute difference −0.3 percentage points (CI −1.2–0.4), P=.38; OR 0.82 (CI 0.54–1.23), P=.33. Keep effects/P separate without copying them as transmission values. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Original estimands, denominators, models/tests, rounding/intervals and direct transmission effects/CI. No RR/risk-difference/CI recalculation. - Required materials and conditions: 42/2392 versus 53/2470, difference and OR - Materials to obtain first: Original estimands, denominators, models/tests, rounding/intervals and direct transmission effects/CI. No RR/risk-difference/CI recalculation. - Further research: Materials needed: Original estimands, denominators, models/tests, rounding/intervals and direct transmission effects/CI. No RR/risk-difference/CI recalculation. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for 42/2392 versus 53/2470, difference and OR together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect 42/2392 versus 53/2470, difference and OR with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N10 · Are self-reported adherence and actual-wearing effects distinguished? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Original self-reports were 46% as recommended, 47% predominantly and 7% not as recommended. Adherence-group denominators/effects and actual exposure details remain unverified. Recommendations are not relabeled as full-wearing/transmission effects, and low adherence is not newly established as the cause of null results. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Adherence definitions, measurement/exposure/missingness, actual group use/contacts and prespecified adherence analyses. No new counts/rates/adherence effects. - Required materials and conditions: 46%/47%/7% versus recommendation effects - Materials to obtain first: Adherence definitions, measurement/exposure/missingness, actual group use/contacts and prespecified adherence analyses. No new counts/rates/adherence effects. - Further research: Materials needed: Adherence definitions, measurement/exposure/missingness, actual group use/contacts and prespecified adherence analyses. No new counts/rates/adherence effects. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for 46%/47%/7% versus recommendation effects together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect 46%/47%/7% versus recommendation effects with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N11 · Are null/wide-CI wearer results separated from unmeasured transmission? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Existing reasons state that the CI retains substantial benefit/harm and does not establish no effect. This concerns wearer uncertainty; transmission was directly unmeasured. No new zero/equivalence or transmission-harms verdict. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Original wearer denominators/CI/models/importance and separate direct transmission comparisons. Parent D does not overwrite the transmission subclaim as D. - Required materials and conditions: Intervals for possible wearer effects versus selected-question gaps - Materials to obtain first: Original wearer denominators/CI/models/importance and separate direct transmission comparisons. Parent D does not overwrite the transmission subclaim as D. - Further research: Materials needed: Original wearer denominators/CI/models/importance and separate direct transmission comparisons. Parent D does not overwrite the transmission subclaim as D. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for intervals for possible wearer effects versus selected-question gaps together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect intervals for possible wearer effects versus selected-question gaps with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N12 · Are contact/cluster/network denominators known? Verification status: Unverified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Because transmission was not measured, direct infection-source/contact/household/cluster/network event/exposure denominators are not provided. The 6,024-person wearer allocation count is not used as a contact/transmission-event denominator. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Direct-transmission design clusters/contacts, enrollment/testing/exposure/ascertainment, secondary events/denominators and correlation/censoring. No new transmission rates, person counts or network values. - Required materials and conditions: Direct-transmission populations at risk and event denominators - Materials to obtain first: Direct-transmission design clusters/contacts, enrollment/testing/exposure/ascertainment, secondary events/denominators and correlation/censoring. No new transmission rates, person counts or network values. - Further research: Materials needed: Direct-transmission design clusters/contacts, enrollment/testing/exposure/ascertainment, secondary events/denominators and correlation/censoring. No new transmission rates, person counts or network values. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for direct-transmission populations at risk and event denominators together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect direct-transmission populations at risk and event denominators with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N13 · Are indirect source-control indicators used to fill the gap? Verification status: Unverified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: The original trial concerns wearer infection and does not answer source control/transmission. Wearer OR/adherence, instructions or mechanistic plausibility do not establish direct transmission effects. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Infection-source/contact ascertainment, transmission direction/timing/exposure and direct secondary infection/effects/CI. Materials distinguishing viral shedding/mechanisms from clinical transmission. - Required materials and conditions: Direct secondary infection versus wearer/mechanistic outcomes - Materials to obtain first: Infection-source/contact ascertainment, transmission direction/timing/exposure and direct secondary infection/effects/CI. Materials distinguishing viral shedding/mechanisms from clinical transmission. - Further research: Materials needed: Infection-source/contact ascertainment, transmission direction/timing/exposure and direct secondary infection/effects/CI. Materials distinguishing viral shedding/mechanisms from clinical transmission. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for direct secondary infection versus wearer/mechanistic outcomes together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect direct secondary infection versus wearer/mechanistic outcomes with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N14 · Are mandates, healthcare and other epidemics separate questions? Verification status: Unverified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Existing advertising interpretation excludes extension to transmission, mandates, healthcare and other variants/epidemics. Recommendation/behavior/cluster-policy effects are not equated without direct materials. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Direct setting/policy populations, interventions/comparators, transmission/infection, cluster/time denominators and effects/CI. No recommendation/mandate/infection-prevention instructions. - Required materials and conditions: Applicability boundaries of a recommendation trial - Materials to obtain first: Direct setting/policy populations, interventions/comparators, transmission/infection, cluster/time denominators and effects/CI. No recommendation/mandate/infection-prevention instructions. - Further research: Materials needed: Direct setting/policy populations, interventions/comparators, transmission/infection, cluster/time denominators and effects/CI. No recommendation/mandate/infection-prevention instructions. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for applicability boundaries of a recommendation trial together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect applicability boundaries of a recommendation trial with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N15 · Are original unblinded, complete-case and missing-data limitations preserved? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: The original design is a nationwide unblinded RCT; the parent records complete-case analysis, 19.3% missingness and one-month follow-up limitations. Concealment/exposure changes, measurement/selection/missing-data handling remain unverified. No official RoB review or new bias grade. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Allocation/behavior/expectations, tests/omissions, missingness/sensitivity and analyses. Original B2 is parent context, not certified transmission review. - Required materials and conditions: Recommendation-trial design and measurement/analysis gaps - Materials to obtain first: Allocation/behavior/expectations, tests/omissions, missingness/sensitivity and analyses. Original B2 is parent context, not certified transmission review. - Further research: Materials needed: Allocation/behavior/expectations, tests/omissions, missingness/sensitivity and analyses. Original B2 is parent context, not certified transmission review. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for recommendation-trial design and measurement/analysis gaps together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect recommendation-trial design and measurement/analysis gaps with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N16 · Are original registration start/posting times preserved? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Existing research wording records start 2020-04-02, first posting 2020-04-08 and six-day retrospective registration. Only original dates/wording are retained; current registration versions/endpoints/plans were not externally compared. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Actual registration/protocol/SAP versions, availability/changes, primary/secondary outcomes and denominators/analyses. Original six days is not a new calculation or certification. - Required materials and conditions: NCT04337541 and six-day retrospective registration - Materials to obtain first: Actual registration/protocol/SAP versions, availability/changes, primary/secondary outcomes and denominators/analyses. Original six days is not a new calculation or certification. - Further research: Materials needed: Actual registration/protocol/SAP versions, availability/changes, primary/secondary outcomes and denominators/analyses. Original six days is not a new calculation or certification. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for nCT04337541 and six-day retrospective registration together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect nCT04337541 and six-day retrospective registration with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N17 · Were mask harms directly quantified? Verification status: Unverified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Existing safety wording explicitly states that mask harms were not quantified and does not establish absence of discomfort/skin irritation. Unassessed is not confirmed as zero events, harmlessness or transmission-harms effects. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Actual group wearing/exposure, harms collection/denominators, discomfort/skin reactions/discontinuation, relatedness and long-term materials. No mask-use/infection-prevention-care instructions. - Required materials and conditions: Discomfort/skin irritation and original lack of harms assessment - Materials to obtain first: Actual group wearing/exposure, harms collection/denominators, discomfort/skin reactions/discontinuation, relatedness and long-term materials. No mask-use/infection-prevention-care instructions. - Further research: Materials needed: Actual group wearing/exposure, harms collection/denominators, discomfort/skin reactions/discontinuation, relatedness and long-term materials. No mask-use/infection-prevention-care instructions. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for discomfort/skin irritation and original lack of harms assessment together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect discomfort/skin irritation and original lack of harms assessment with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N18 · What materials were actually read or acquired? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: The complete parent summary was read for production and preserved in its original form. Summary reading concerns preserved materials; external abstracts/full texts/registrations/protocols/SAP remain unread. Original citations/URLs do not establish external reading here. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Records of actual acquisition/reading scope, versions and dates. No external-link/click/access testing. - Required materials and conditions: Preserved summary versus external materials - Materials to obtain first: Records of actual acquisition/reading scope, versions and dates. No external-link/click/access testing. - Further research: Materials needed: Records of actual acquisition/reading scope, versions and dates. No external-link/click/access testing. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for preserved summary versus external materials together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect preserved summary versus external materials with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N19 · Are historical registration/prespecification and current reading separated? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Preserve original NCT04337541, start 2020-04-02/first posting 2020-04-08 and six-day retrospective-registration wording. Actual versions/plans/access remain unread here; official URLs are not guessed. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Actual registration versions/availability, recruitment/start/changes, endpoints/models/analyses and original-report linkage. Only history is preserved, with no current plan/prespecification certification. - Required materials and conditions: Original registration identifier, timing and plans - Materials to obtain first: Actual registration versions/availability, recruitment/start/changes, endpoints/models/analyses and original-report linkage. Only history is preserved, with no current plan/prespecification certification. - Further research: Materials needed: Actual registration versions/availability, recruitment/start/changes, endpoints/models/analyses and original-report linkage. Only history is preserved, with no current plan/prespecification certification. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for original registration identifier, timing and plans together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect original registration identifier, timing and plans with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N20 · Have protocol/SAP and analysis/missing-data plans been acquired? Verification status: Unverified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Original primary/analysis/registration wording and historical cross-validation are preserved. Actual protocol/SAP, versions/timing, endpoint-specific models/missingness and hierarchy/multiplicity were not read here. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Original protocol/SAP/revisions, estimands/denominators/analyses, all endpoints and availability timing. Unread is not declared document absence. - Required materials and conditions: Separate materials for prespecified plans/changes - Materials to obtain first: Original protocol/SAP/revisions, estimands/denominators/analyses, all endpoints and availability timing. Unread is not declared document absence. - Further research: Materials needed: Original protocol/SAP/revisions, estimands/denominators/analyses, all endpoints and availability timing. Unread is not declared document absence. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for separate materials for prespecified plans/changes together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect separate materials for prespecified plans/changes with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N21 · Are sponsorship/funding, products, authors and research roles separated? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Preserve Salling Foundations funding, Rigshospitalet leadership and study-supplied masks. Manufacturer donation/medical-writing/publication-cost support was not verified in the original; company funding, employee authors and design/analysis roles remain separately unverified. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Individual original company cash funding, product support, employee authors/outside relationships, design/analysis/data control and other institutional support. Original I2 is not new certification of all items/independence. - Required materials and conditions: Four company-involvement items and institution/foundation support - Materials to obtain first: Individual original company cash funding, product support, employee authors/outside relationships, design/analysis/data control and other institutional support. Original I2 is not new certification of all items/independence. - Further research: Materials needed: Individual original company cash funding, product support, employee authors/outside relationships, design/analysis/data control and other institutional support. Original I2 is not new certification of all items/independence. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for four company-involvement items and institution/foundation support together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect four company-involvement items and institution/foundation support with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N22 · Are directly unmeasured, null and unverified outcomes distinguished? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Distinguish null wearer infection/wide CI from directly unmeasured transmission, absent contact denominators and unread details. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Original direct-measurement/endpoint tables, estimands/denominators, plans and actual-access records. Unread is not unreported, and null is not exactly zero/equivalence. - Required materials and conditions: Question/results versus access gaps - Materials to obtain first: Original direct-measurement/endpoint tables, estimands/denominators, plans and actual-access records. Unread is not unreported, and null is not exactly zero/equivalence. - Further research: Materials needed: Original direct-measurement/endpoint tables, estimands/denominators, plans and actual-access records. Unread is not unreported, and null is not exactly zero/equivalence. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for question/results versus access gaps together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect question/results versus access gaps with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N23 · Are reports, trials, people, tests/timepoints and sibling sheets separated? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Parent 2971 and existing s0/s1 share the same DANMASK-19 report, 6,024 allocated and 4,862 complete cases. People/groups/tests/events/timepoints/bibliographies/sibling sheets are not summed as independent trials/participants; wearer denominators do not fill other-person denominators. Linked-report counts do not certify unique totals. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Original report/registration, cohort/test/timepoint, event/repetition/observation and overlap relationships. Unique trials/participant totals remain not recorded. - Required materials and conditions: Linked records versus unique trials/participants - Materials to obtain first: Original report/registration, cohort/test/timepoint, event/repetition/observation and overlap relationships. Unique trials/participant totals remain not recorded. - Further research: Materials needed: Original report/registration, cohort/test/timepoint, event/repetition/observation and overlap relationships. Unique trials/participant totals remain not recorded. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for linked records versus unique trials/participants together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect linked records versus unique trials/participants with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N24 · Are the original single trial and separate replication distinguished? Verification status: Unverified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Preserve parent R1/I2 and the single-trial scope. Timepoints/endpoints in the same people and sibling sheets do not certify new independent replication. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Separate prespecified direct population/intervention/comparator/endpoint/period, denominators/effects/CI and disclosed funding/author relationships for the selected question. No new search/independence judgment. - Required materials and conditions: Parent R1/I2, follow-up and confirmation - Materials to obtain first: Separate prespecified direct population/intervention/comparator/endpoint/period, denominators/effects/CI and disclosed funding/author relationships for the selected question. No new search/independence judgment. - Further research: Materials needed: Separate prespecified direct population/intervention/comparator/endpoint/period, denominators/effects/CI and disclosed funding/author relationships for the selected question. No new search/independence judgment. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for parent R1/I2, follow-up and confirmation together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect parent R1/I2, follow-up and confirmation with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N25 · Are the subclaim grade and parent score/axes preserved? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Preserve selected grade/note and both question languages. Absent subclaim score/status/axes remain not recorded. Parent D34, safety and axes are parent context and are not transferred as a selected score. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Existing subclaim/parent-boundary review and actual correction materials. No new grade/score or official RoB 2/GRADE certification. - Required materials and conditions: Selected ? grade, absent subclaim values and parent D34 - Materials to obtain first: Existing subclaim/parent-boundary review and actual correction materials. No new grade/score or official RoB 2/GRADE certification. - Further research: Materials needed: Existing subclaim/parent-boundary review and actual correction materials. No new grade/score or official RoB 2/GRADE certification. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for selected ? grade, absent subclaim values and parent D34 together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect selected ? grade, absent subclaim values and parent D34 with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N26 · Are both languages, citations and absent fields preserved? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Preserve parent Korean/English citations/descriptions, evidence/citation lists, axes and selected-subclaim records in the complete summary. Separate classification information in both languages is absent; originals are not filled with new fields. No external English full-text comparison. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Review materials for terminology, endpoints/effects/test units, selected scope and absent fields in both languages. Production explanations are distinguished from original records. - Required materials and conditions: Both original languages and absent separate classification information - Materials to obtain first: Review materials for terminology, endpoints/effects/test units, selected scope and absent fields in both languages. Production explanations are distinguished from original records. - Further research: Materials needed: Review materials for terminology, endpoints/effects/test units, selected scope and absent fields in both languages. Production explanations are distinguished from original records. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for both original languages and absent separate classification information together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect both original languages and absent separate classification information with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N27 · Are source dates/corrections/history separated from production dates? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Preserve original 2026-08-26, empty corrections/deliberation and verdict-decision cross-validation. Original citation/registration wording differs from current production/condition freezing/application or completed content review. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Update materials separating originals, events, conditions/observations and verdict decisions when new evidence/corrections arise. Historical wording is not completed clinical content review here. - Required materials and conditions: Original 2026-08-26 and new conditions/application - Materials to obtain first: Update materials separating originals, events, conditions/observations and verdict decisions when new evidence/corrections arise. Historical wording is not completed clinical content review here. - Further research: Materials needed: Update materials separating originals, events, conditions/observations and verdict decisions when new evidence/corrections arise. Historical wording is not completed clinical content review here. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for original 2026-08-26 and new conditions/application together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect original 2026-08-26 and new conditions/application with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N28 · What direct materials would fill the selected gaps? Verification status: Unverified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: Transmission gaps require direct infection-source/contact/cluster/network ascertainment/observation and effects/CI. Null one-month wearer results or mechanisms do not substitute for them. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Original tables/plans, direct populations/comparators/endpoints, estimands/CI, observation/tests/denominators, actual exposure/adherence, separate confirmation and long-term harms. Only needs are recorded; no new search/research. - Required materials and conditions: Direct endpoints, estimands/CI and denominators/follow-up - Materials to obtain first: Original tables/plans, direct populations/comparators/endpoints, estimands/CI, observation/tests/denominators, actual exposure/adherence, separate confirmation and long-term harms. Only needs are recorded; no new search/research. - Further research: Materials needed: Original tables/plans, direct populations/comparators/endpoints, estimands/CI, observation/tests/denominators, actual exposure/adherence, separate confirmation and long-term harms. Only needs are recorded; no new search/research. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for direct endpoints, estimands/CI and denominators/follow-up together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect direct endpoints, estimands/CI and denominators/follow-up with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ### N29 · Are applicability records separated from content review and instructions? Verification status: Partly verified Reading scope: Preserved summary read; external abstracts/full texts/registrations/protocols/SAP remain unread - Current findings: These are summary-based applicability records. Existing content/question-boundary review remains incomplete; candidate pending/eligible markers are preserved as history. - Why unverified: Production observation distinguishing selected/parent, report and endpoint materials in the preserved summary. Detailed original materials remain unverified and existing content review is incomplete; this does not establish completed clinical review or certification. - Reason for missing information: Existing content review and later actual-material/correction work. Historical production did not perform clinical original-material comparison, external access, new calculations, grade changes or mask/infection-prevention/treatment-replacement instructions. - Required materials and conditions: Applicability records, existing candidate history and content review - Materials to obtain first: Existing content review and later actual-material/correction work. Historical production did not perform clinical original-material comparison, external access, new calculations, grade changes or mask/infection-prevention/treatment-replacement instructions. - Further research: Materials needed: Existing content review and later actual-material/correction work. Historical production did not perform clinical original-material comparison, external access, new calculations, grade changes or mask/infection-prevention/treatment-replacement instructions. Only material requests/research needs are recorded; no search or research was performed in that production. - Conditions for verification: Show original materials for applicability records, existing candidate history and content review together with selected-subclaim/parent boundaries, direct endpoints/estimands/denominators and the scope of external reading. - Why this condition is needed: Needed to connect applicability records, existing candidate history and content review with the selected question, actual population/intervention/comparator, endpoints/estimands, denominators/tests/follow-up and reports/harms. - Application exceptions: Distinguish recommendation/distribution, actual wearing/adherence, wearer infection, transmission/source control, contact/cluster/network denominators, one month/period, complete cases/missingness, effects/CI and harms. Only original numbers are retained; no new calculations, invented quantities, effects/CI, grades/reassessment, independence certification or mask/infection-prevention/treatment-replacement instructions. - Remaining uncertainty: External original materials remain unread and existing content review is incomplete. Original grades/scores/axes and historical verification/independence descriptions are not upgraded to new verdicts/certification. - Referenced methods: Existing C/E/H distinctions of questions, populations, interventions, comparisons, reports/trials, endpoints/denominators and harms referenced for production - Related sources: R01 ## Evidence and sources ### R01 Bundgaard H, et al. Effectiveness of Adding a Mask Recommendation to Other Public Health Measures to Prevent SARS-CoV-2 Infection in Danish Mask Wearers. Ann Intern Med. 2021;174:335-343. PMID: 33205991. [PubMed](https://pubmed.ncbi.nlm.nih.gov/33205991/) Materials actually read: Preserved summary read; external abstracts/full texts/registrations/plans remain unread Findings recorded in the summary: 42/2,392(1.8%) versus 53/2,470(2.1%); difference −0.3 percentage points (−1.2–0.4), P=.38; OR 0.82(0.54–1.23), P=.33 Record level: Parent-endpoint summary in the original evidence list; directness/scope for selected/other endpoints are distinguished in condition rows/roles Independent replication: Parent 2971 and existing s0/s1 share the same DANMASK-19 report, 6,024 allocated and 4,862 complete cases. People/groups/tests/events/timepoints/bibliographies and sibling sheets are not summed as independent trials/participants; wearer denominators do not fill other-person denominators. Only report/registration/follow-up relationships are linked, without certification of unique trials/participants or independence. | Material | Public availability | Access status | Actually read | Notes | |---|---|---|---|---| | Stored summary | Local preserved copy of the complete parent summary | Stored summary read | Summary read | Only original PubMed URL/bibliography and original shared-registration wording are preserved; full-text/registration/plan URLs are not guessed. No new external reading/access or fulfillment certification. | | External abstract | Original identifier/bibliography or required-material entry; public availability/access details remain unverified | Unread; access testing not performed | Not read | Only original PubMed URL/bibliography and original shared-registration wording are preserved; full-text/registration/plan URLs are not guessed. No new external reading/access or fulfillment certification. | | External full text | Original identifier/bibliography or required-material entry; public availability/access details remain unverified | Unread; access testing not performed | Not read | Only original PubMed URL/bibliography and original shared-registration wording are preserved; full-text/registration/plan URLs are not guessed. No new external reading/access or fulfillment certification. | | Registration material | Original identifier/bibliography or required-material entry; public availability/access details remain unverified | Unread; access testing not performed | Not read | Only original PubMed URL/bibliography and original shared-registration wording are preserved; full-text/registration/plan URLs are not guessed. No new external reading/access or fulfillment certification. | | Protocol/SAP | Original identifier/bibliography or required-material entry; public availability/access details remain unverified | Unread; access testing not performed | Not read | Only original PubMed URL/bibliography and original shared-registration wording are preserved; full-text/registration/plan URLs are not guessed. No new external reading/access or fulfillment certification. | ## Review criteria and methods These are Chamgap's own application conditions, informed by the relevant sections of official methodological guidance. They do not constitute official assessment-tool certification or a new efficacy score. - M03 [Cochrane Handbook 6.5 (2024), chapter updated 2023-08](https://www.cochrane.org/authors/handbooks-and-manuals/handbook/current/chapter-03) · §3.1, §3.2.1–3.2.3, MECIR C5/C7/C13 · Clearly record the question, eligibility conditions and reasons for changes, and distinguish variations in interventions. · Link preserved methodological application records; no current clinical-content reassessment or external-link verification was performed. - M04 [Cochrane Handbook 6.5.1 (2025), chapter updated 2025-03](https://www.cochrane.org/authors/handbooks-and-manuals/handbook/current/chapter-04) · §4.5, §4.6.1–4.6.3, MECIR C42 · Distinguish studies from reports and link them; do not omit a study solely because results are unreported. · Link preserved methodological application records; no current clinical-content reassessment or external-link verification was performed. - M08 [Cochrane Handbook 6.5 (2024), chapter updated 2019-10](https://www.cochrane.org/authors/handbooks-and-manuals/handbook/current/chapter-08) · §8.1–8.2.3, Table 8.2.a · Define the outcome and effect of interest, then examine randomization, deviations, missing data, measurement and selective reporting. · Link preserved methodological application records; no current clinical-content reassessment or external-link verification was performed. - M15 [Cochrane Handbook 6.5 (2024), chapter updated 2023-08](https://www.cochrane.org/authors/handbooks-and-manuals/handbook/current/chapter-15) · §15.2.4, §15.3.1–15.3.3 · Distinguish effect estimates, intervals, importance and applicability. Sample size alone does not determine precision. · Link preserved methodological application records; no current clinical-content reassessment or external-link verification was performed. - M19 [Cochrane Handbook 6.5 (2024), chapter updated 2019-10](https://www.cochrane.org/authors/handbooks-and-manuals/handbook/current/chapter-19) · §19.1.2, §19.2.1–19.2.4 · Harm questions may require different designs, populations and follow-up from efficacy questions. Case reports do not establish incidence rates. · Link preserved methodological application records; no current clinical-content reassessment or external-link verification was performed. ## What the statuses mean - Partly verified: Some information exists in the preserved review summary; detailed original materials remain unverified. This does not certify a passed review or clinical efficacy. - Unverified: Detailed materials for the selected condition could not be established within the stored scope; this does not mean zero effect, zero studies or safety - Review incomplete: Review of existing content incomplete - Met: Use only within the relevant conditions after existing content review; no automatic designation in this preparation - Not reported: Distinguish only within materials actually read; do not turn unread external materials into unreported findings - Inaccessible: Not applied during this preparation because actual access was not tested - Not applicable: Use with a reason for non-applicability based on an explicit question boundary - Conflicting data: Judge after actual material comparison; review was not performed during this preparation - Insufficient evidence for the conditions: Do not use as a clinical grade encompassing currently unread materials ## Change history 2026-10-14 · Public page/materials 1.0. Public pages and materials were created from the existing 29 items. No new clinical search, verification-status change or scoring was performed.