Although the World Health Organization decided not to recommend the use of RTS,S/AS01, the most advanced malaria vaccine candidate that is in development, in infants within the Expanded Programme of Immunisations (EPI), termination of further development of RTS,S/AS01 would be a loss for malaria elimination efforts according to Roly Gosling of the UCSF Global Health Group's Malaria Elimination Initiative and Lorenz von Seidlein of the Mahidol-Oxford Tropical Medicine Research Unit, Thailand.
Last year a large Phase III trial of RTS,S/AS01 in both infants aged 6 to 12 weeks and young children 5 to 15 months old, showed that vaccine efficacy waned rapidly and the addition of a booster dose 20 months after the first dose increased protection only slightly. While these findings are disappointing the authors argue that the potential benefit of the high initial protection afforded by the vaccine should not be forgotten and, following further research, the vaccine could potentially be used in intensive malaria elimination strategies in low-endemicity areas to interrupt transmission of the parasite.
The authors conclude, "a new tool for malaria control, RTS,S/AS01, is now available. Although its performance is somewhat disappointing in sub-Saharan African children, the vaccine's short-term efficacy could potentially be used in other regions and other age groups. Global efforts are currently underway to eliminate malaria, with a special focus in Southeast Asian areas with low malaria incidence and high antimalarial drug resistance. Integration of RTS,S/AS01 into elimination strategies may improve the chances of success."
The authors received no specific funding for this work.
I have read the journal's policy and have the following conflicts: LvS worked from 2006 through 2008 on trials to evaluate RTS,S in Tanzania while being employed by the London School of Hygiene and Tropical Medicine (LSHTM). The LSHTM has received extensive funding from the Malaria Vaccine Initiative for the evaluation of RTS,S. LvS receives a stipend as a specialty consulting editor for PLOS Medicine and serves on the journal's editorial board. RG declares no competing interests.
Gosling R, von Seidlein L (2016) The Future of the RTS,S/AS01 Malaria Vaccine: An Alternative Development Plan. PLoS Med 13(4): e1001994. doi:10.1371/journal.pmed.1001994
Global Health Group, University of California, San Francisco, San Francisco, California, United States of America
Mahidol-Oxford Tropical Medicine Research Unit (MORU), Bangkok, Thailand
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