29 Jun This Generation of Malaria Vaccine Not Perfect But Can Still Save Lives
MedicalResearch.com Interview with:
Philip Bejon, Ph.D.
Professor of Tropical Medicine, Director of the Wellcome-KEMRI-Oxford Collaborative Research Programme, Group Head / PI, Consultant Physician and Unit Director
MedicalResearch.com: What is the background for this study?
Response: According to the latest World Health Organisation (WHO) estimates more than 400,000 people died from malaria in 2015, with over 90% of these deaths occurring in sub-Saharan Africa. The vast majority who die are children under 5, and almost all cases are caused by the P. falciparum strain of malaria transmitted by female Anopheles mosquitoes.
RTS,S, which protects only against P. falciparum, was developed by GlaxoSmithKline with support from the PATH Malaria Vaccine Initiative (MVI) and with grant funds from the Bill & Melinda Gates Foundation to MVI. In July 2015, it received a positive opinion from the European Medicines Agency.
Earlier this year, the WHO recommended further evaluation of the four-dose regimen of RTS,S in a pilot implementation programme in sub-Saharan Africa, to address several knowledge gaps before the vaccine might be rolled out more widely.
MedicalResearch.com: What are the main findings?
Response: We followed 447 children who had received three doses of either RTS,S or a rabies (control) vaccine when they were 5 to 17 months old over 7 years. During the first year, the risk of getting malaria in the vaccinated children was 35.9% less than in the control group, but after seven years this protection fell to 4.4%.
In children exposed to the higher than average rates of malaria, there were slightly more cases of the disease (1002 cases) in the vaccinated group compared with the control group (992 cases) five years after vaccination. This ‘rebound’ effect is thought to occur because children protected by RTS,S develop their natural immunity against malaria more slowly than unvaccinated children, and has been seen in previous studies.
MedicalResearch.com: What should readers take away from your report?
Response: The malaria vaccine is being carefully evaluated for long-term outcomes. A final decision on implementation will take account of further data on a four-dose regimen.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: Implementation trials and long-term follow up data with a four dose regimen are essential.
MedicalResearch.com: Is there anything else you would like to add?
Response: research shows that there is real value in studying the impact of a vaccine over the long term to understand how protection can change over time.
The results suggest that the implementation of RTS,S will need to be considered carefully and in a way that takes into account different levels of malaria exposure. RTS,S isn’t perfect, but it still has the potential to save lives and will provide an important springboard for improved second generation vaccines that target multiple stages of the malaria parasite’s lifecycle.
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Seven-Year Efficacy of RTS,S/AS01 Malaria Vaccine among Young African Children
Ally Olotu, Ph.D., Gregory Fegan, Ph.D., Juliana Wambua, M.Sc., George Nyangweso, B.Sc., Amanda Leach, M.R.C.P.C.H., Marc Lievens, M.Sc., David C. Kaslow, M.D., Patricia Njuguna, M.Med., Kevin Marsh, F.R.C.P., and Philip Bejon, Ph.D.
N Engl J Med 2016; 374:2519-2529June 30, 2016
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