Single-dose typhoid conjugate vaccine,
does it really help with Prevention of blood-culture-confirmed typhoid over two years in children aged 9 months to 15 years in an endemic setting?
research showsThe grade is B with 76 points. In a Nepal trial randomizing 20,019 children, culture-confirmed typhoid over two years occurred in 13/10,005 vaccine recipients and 62/10,014 control-vaccine recipients, for 79.0% efficacy (95% CI 61.9 to 88.5). The protocol, interim, and final papers are reports of one trial, not independent replications.
ads claimThe conjugate formulation and the two-year clinical efficacy are both supported in this trial. Three papers from one trial must not be marketed as three replications or transferred directly to a different manufacturer's product.
Useful facts when choosing a product
- The study product contained 25 micrograms of Vi polysaccharide conjugated to tetanus toxoid in a single 0.5 mL dose.
- The control was MenAfriVac, helping maintain participant masking.
- All three reports map to ISRCTN43385161.
What the research actually shows
The trial assigned 10,005 children to TCV and 10,014 to MenA control vaccine. The primary two-year outcome was 13 versus 62 cases, efficacy 79.0% (61.9 to 88.5), P<0.0001. The report states: “Participants were enrolled and randomly assigned during the vaccination visit by means of 1:1 stratified block randomisation, with random block sizes of 6–12 by means of an offline mobile application built for the purpose.” Assignment by the purpose-built offline app at the vaccination visit, using random block sizes of 6–12, prevented advance prediction. It also states: “We did a participant-masked and observer-masked individually randomised trial…” All assigned participants were included in event surveillance, the prespecified registered primary endpoint matched the published primary endpoint, and participant and observer masking was maintained. Funding came from the Bill & Melinda Gates Foundation, with an initial investigational-vaccine donation from the manufacturer. PMID 30845329 is the protocol for the same registration and sample; PMIDs 31800986 and 34678198 are interim and final reports of that same trial.
Why this is classified as B (76)
A large randomized hard-outcome trial found a substantial effect, but it remains one trial with mixed funding and product support, giving B with 76 points.
Counterpoint. Local reactions and fever can occur; severe allergy history and acute illness should be reviewed with a vaccination professional.
Rejudgment record. Cross-check applied — Cross-checked the final and interim efficacy reports, protocol, and registry for trial identity, primary outcome, denominators, masking, and funding
| Endpoint | H | Hard endpoint - actual events such as death |
| Replication | R1 | Single confirmatory trial |
| Independence | I1 | Mixed funding sources |
| Effect size | E+ | Meets the clinically important threshold |
The scoring table and the verdict agree (B).
Sub-claim grades by effect
This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.
| Effect (sub-claim) | Grade | Basis |
|---|---|---|
| Prevention of culture-confirmed typhoid over two years | B | There were 13 versus 62 cases, for 79.0% efficacy. |
Cross-check — Codex and Claude
Evidence Table
| Study | Design | Sample | Funding | Endpoint | Result | Weight |
|---|---|---|---|---|---|---|
| Study 1 | Phase 3 individually randomized participant- and observer-masked active-control trial | 10,014 | Bill & Melinda Gates Foundation; initial investigational-vaccine donation from the manufacturer | Blood-culture-confirmed typhoid from 14 days after vaccination through two years | 13/10,005 versus 62/10,014; efficacy 79.0% (95% CI 61.9 to 88.5), P<0.0001 | Pivotal large hard-outcome single trial; multiple papers are reports of the same trial |
Receipt — 3 References
All 3 cited sources were verified for existence at the original page (as of 2026-08-15).
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-08-15 · Corrections: none
Cite this verdict
[Chamgap] Single-dose typhoid conjugate vaccine x prevention of culture-confirmed typhoid over two years — Evidence Grade B·76. 3 cited sources checked. Source: https://chamgap.com/en/verdicts/gut/typhoid-conjugate-vaccine-culture-confirmed-typhoid/ · CC BY 4.0CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.
What this document does and does not do
Chamgap is an information source. It reports what research has and has not confirmed; it does not tell readers what to take or buy. That decision belongs to readers and, when needed, medical or legal professionals. This verdict reflects literature available up to the search date and may change as new research appears. Nothing here is medical advice.