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50 years of vaccination: lives saved

Contribution of vaccination to improved survival and health: modelling 50 years of the Expanded Programme on Immunization.

Overview

Shattock AJ et al.. Lancet 2024 · PMID 38705159 · DOI 10.1016/S0140-6736(24)00850-X

Vaccines against 14 diseases averted an estimated 154 million deaths since 1974 (about 94 million by measles vaccine alone), mostly in young children.

Does the study support the specific claim? No · Methodological quality: moderate

Original publication

Plain-language summary

Study explained simply

What did the researchers want to find out?: Estimate deaths averted by vaccination
How was the study done?: Modelling
How many people, animals or samples were studied?: Global
What was actually found?: 154 million deaths averted
How large was the observed effect?: 40% of infant-mortality decline
What do the results mean in everyday life?: Vaccination is one of the main reasons far fewer children die today.
What are the study's limitations?: Model-based counterfactual; no formal uncertainty bounds; WHO-funded with WHO-linked authors
What does it say about Elawady's specific claim?: Contradicts 'no vaccinations'.
Do the results apply to Germany and Europe?: High
What can explicitly not be concluded from this study?: Model estimates are not direct observations.

Scientific in-depth review

1. Full reference

Authors: Shattock AJ et al.
Journal: Lancet
Year: 2024
Identifier: PMID 38705159 DOI 10.1016/S0140-6736(24)00850-X
Verification: verified – PubMed efetch 2026-10-25
Retracted: no
Corrections: none
Extent checked: full text
Conflicts of interest and funding: Funded by WHO (funder had no role in design, analysis or writing per full text); several authors work for WHO; several authors' institutions receive Vaccine Impact Modelling Consortium funding from the Gates Foundation, Gavi and Wellcome; one author received GSK consulting fees (CMV vaccine advisory board). Data and code publicly available (GitHub/Zenodo).

2. Research question

How many deaths has vaccination averted since 1974?

3. Study design and population

Study design: Risk assessment – Modelling study synthesising 22 models (dynamic transmission models for measles and polio, extended VIMC models for 6 pathogens, static models for diphtheria, tetanus, pertussis, tuberculosis) with regression-based imputation, counterfactual of no historical vaccination
Population: Populations of 194 WHO member states, all ages
Country: Global (194 WHO member states), with regional results incl. Eastern Mediterranean region
Period: 1 June 1974 to 31 May 2024
Sample size: not applicable
Inclusion and exclusion criteria: 14 pathogens included (diphtheria, Hib, hepatitis B, Japanese encephalitis, measles, meningitis A, pertussis, pneumococcus, polio, rotavirus, rubella, tetanus, tuberculosis, yellow fever); routine and supplementary immunisation coverage from WHO and VIMC sources. Excluded: smallpox (counterfactual assumes smallpox-free world), HPV, influenza, COVID-19, outbreak vaccines (cholera, Ebola), adult and high-income-only vaccines; heterologous/non-specific effects not modelled.

4. Methods and endpoints

Exposure / intervention: Historical routine and supplementary vaccination coverage (24 vaccine activities)
Comparator: Hypothetical no-vaccination scenario
Endpoints: Deaths averted, life-years gained, years of full health gained (DALYs averted), share of infant mortality decline attributable to vaccination, age-specific survival gain in 2024
Statistical methods: Transmission and static models; time-series regression imputation with AICc covariate selection for countries without VIMC estimates; functional fits (linear, logarithmic, exponential, sigmoidal) of cumulative impact vs fully vaccinated persons with MCMC and AIC selection; Bernoulli correction for double counting; coverage for 1974-79 extrapolated. Authors state credible intervals have arbitrary widths and should not be interpreted as bounds.

5. Actual results

Results: 154 million deaths averted 1974-2024, incl. 146 million in children <5 years and 101 million infants; 9.0 billion life-years and 10.2 billion years of full health gained (on average 58 life-years and 66 years of full health per death averted). Measles vaccination accounted for 93.7 million (60.8%) of lives saved; tetanus 27.9 million; pertussis 13.2 million; tuberculosis 10.9 million; Hib 2.8 million; polio 1.6 million deaths (but 0.8 billion healthy years via paralysis averted). Vaccination accounted for 40% of the global decline in infant mortality (21% Western Pacific to 52% African region). In 2024 children aged 10 years are about 44% more likely to survive to their next birthday than without vaccination (abstract: children <10 years 40%), age 25 35%, age 50 16%. Largest absolute survival gains in the Eastern Mediterranean and African regions. Double counting effect about 0.01%.
Absolute risks: 154 million deaths averted (modelled); absolute survival gains largest in Eastern Mediterranean and African regions (percentage-point values shown in figure only)
Authors' conclusion: EPI has provided the single greatest contribution to improved infant survival over the past 50 years.

6. Strengths

Most comprehensive historical vaccine impact estimate (14 pathogens, 194 countries, 50 years)
Combines dynamic and static models capturing direct and herd effects
Validated against earlier, more restricted analyses; methods reviewed by a WHO advisory committee
Open data and code

7. Weaknesses

Counterfactual (no vaccination) cannot be observed; results depend on model structure and assumptions
No interpretable uncertainty intervals for final estimates (authors' statement)
Extrapolation/imputation for countries and years without model estimates; 1974-79 coverage extrapolated
Static models for 4 pathogens rely on GBD 2021 burden and efficacy assumptions
Excludes smallpox, HPV, influenza, COVID-19 and non-specific effects (authors consider estimate conservative)
Commissioned and funded by WHO; many authors linked to WHO, Gavi or Gates-funded consortia

8. Risk of bias

Orienting tool: No standard tool fits (modelling study); structured validity judgement
Type of assessment: structured assessment based on the full text by a single reviewer (no formal double review)
Full formal assessment: no
Overall risk of bias: some concerns
Rationale: Overall unchanged. Magnitude is model-dependent and lacks formal uncertainty bounds, but the direction (large mortality reduction from vaccination) is consistent with surveillance data and trial-based vaccine efficacy. Simplified single-reviewer judgement; no formal tool applied.

8. Risk of bias
Domain	Judgement	Rationale
Model structure and assumptions	some concerns	Established published models, but counterfactual and functional-form choices drive magnitude.
Input data quality	some concerns	Coverage data taken as given without uncertainty; early-period coverage extrapolated; GBD inputs.
Uncertainty quantification	high	Full propagation of uncertainty not possible; credible intervals of arbitrary width, not reported as bounds.
Validation and transparency	low	Compared with previous analyses; open code and data; external advisory review.
Independence / conflicts	some concerns	WHO-funded anniversary analysis with WHO-employed authors and Gates/Gavi-funded modelling groups; funder said to have had no role.

Full-text review (25 October 2026): Added model structure (22 models, 14 pathogens, 194 countries), exclusions, pathogen-specific deaths averted (measles 93.7 million, 60.8%), life-years and healthy years, regional infant-mortality shares, age-specific survival gains (10 years ~44%), authors' statement that credible intervals are not interpretable bounds, open code, funding and COI details. Bias overall unchanged with structured domains.

9. Assessment of the statistical interpretation

Point estimates from counterfactual models without interpretable uncertainty intervals; measles vaccination dominates the estimate. Direction robust, exact magnitude uncertain.

10. Relevance to the specific claim

Contradicts a blanket ban on vaccination.

11. Independent contrary findings

Model-based; not direct trial evidence.

12. Transferability to Germany and Europe

Global.

13. Overall methodological judgement

Strong population-level evidence (model-based) that vaccination has averted very large numbers of deaths, especially among young children; directly contradicts a blanket prohibition of vaccination.

Multidimensional assessment
Multidimensional assessment
Authenticity of the source	verified
Methodological quality	moderate
Risk of bias	some concerns
Precision of results	moderate
Directness	direct
Reproducibility	partly replicated
Consistency with the overall evidence	consistent
Regional transferability	high
Adequacy of the interpretation (by the archive)	not applicable

14. Open questions

15. Linked fact checks

There are to be no vaccinations: vaccinations, medicines and herbs are forbidden. – Studies contradicting or limiting the claim