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Published on: November 1, 2011
RTS,S/AS01 malaria vaccine-proven safe and effective?
Anders Björkman1, Christine Stabell Benn2, Peter Aaby3
1Department of Global Public Health, Karolinska Institutet, Stockholm, Sweden.
Insights
The RTS,S malaria vaccine
Area of Science:
- Global Health
- Vaccinology
- Pediatric Infectious Diseases
Background:
- The World Health Organization (WHO) recommended the RTS,S malaria vaccine in October 2021 for children aged 5 months and older in high-transmission areas.
- Recommendations were based on Phase 3 trials and an ongoing Malaria Vaccine Implementation Programme (MVIP).
Purpose of the Study:
- To critically evaluate the mortality data from the Malaria Vaccine Implementation Programme (MVIP).
- To assess the scientific evidence supporting the claimed impact of the RTS,S vaccine on child mortality.
Main Methods:
- Analysis of potential confounding factors in MVIP mortality data.
- Review of the statistical significance and duration of the MVIP assessment.
- Comparison of MVIP findings with Phase 3 trial results, particularly regarding sex-specific mortality.
Main Results:
- Identified significant issues with MVIP mortality data, including potential confounding and inappropriate use of surrogate markers.
- The observed effect on mortality was not statistically significant, and the assessment period was shorter than planned.
- Concerns remain regarding potential increased mortality in vaccinated girls compared to boys, as suggested by Phase 3 data.
Conclusions:
- The claimed mortality benefits of the RTS,S vaccine in the MVIP are not supported by robust scientific evidence.
- Further rigorous evaluation, including independent data assessment and adherence to planned analyses, is necessary.
- Future vaccine roll-outs must prioritize comprehensive safety evaluations, especially concerning sex-specific mortality differences.
Abstract:
In October, 2021, WHO recommended that the RTS,S malaria vaccine, with its strong safety profile and high impact, be provided to children from age 5 months in regions with moderate to high Plasmodium falciparum malaria transmission. The evidence base included phase 3 trials in seven African countries and an ongoing malaria vaccine implementation programme (MVIP) in three African countries. We highlight problems with the MVIP mortality data, including potential confounding, inappropriate use of severe malaria as a surrogate marker, a statistically non-significant effect, and assessment after 2 years instead of the stipulated 4 years, which could have inflated the benefits and deflated the risks associated with the vaccine. We conclude that the claimed impact of the MVIP on mortality is not based on enough scientific evidence and that the MVIP findings do not rule out the possibility of increased mortality among vaccinated girls compared with vaccinated boys, as observed in the phase 3 studies. The MVIP should adhere fully to the planned analyses and the data should be made available for independent assessment. Roll-out of the vaccine elsewhere should include rigorous evaluation, especially of its safety.
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