Dual strategies for malaria treatment recommendedCredit: Getty Images/EyeEm
A combination of seasonal malaria vaccination and seasonal chemoprevention drugs (SMC) has the potential to provide substantial protection against the disease for longer than five years, a new study suggests.
In the study, published in Lancet Infectious Diseases, the researchers enrolled 5098 children in Mali and Burkina Faso in a two year clinical trial, to establish whether the added protection provided by a vaccine and antimalarial drug combination could be sustained for a further two years after participants, aged between 5 and 17 months, had already been enrolled in a three year trial. They were given SMC with sulphadoxine-pyrimethamine (SP) and amodiaquine plus control vaccines, RTS, S/AS01E plus placebo SMC, or SMC plus RTS,S/AS01E.
The results showed promising outcomes. Over the course of five years, the combination of RTS,S/AS01E and SMC demonstrated superior protection compared to SMC alone and RTS,S/AS01E alone, with a protective efficacy of approximately 57.7% to 59.0%. The combined approach significantly reduced mortality, hospital admissions for severe malaria, cases of malarial anemia, the need for blood transfusions, and mortality. No safety concerns were identified.
The study’s corresponding author, Brian Greenwood, from the London School of Hygiene and Tropical Medicine, says that countries of the Sahel and sub-Sahara where over half of all cases of malaria in Africa occur, have malaria cases largely restricted to the three to five months when it rains and the anopheles mosquitoes thrive.
“Although SMC is quite effective, giving around 70% protection, many children still get malaria,” said Greenwood. He told Nature Africa, that RTS,S on the other hand, is “only an imperfect vaccine and the protection against malaria that it provides drops off quickly a few months after the first three doses or a subsequent booster dose is given,” thus the decision to test the RTS,S plus SMC.
“In areas like the Kisumu area of Kenya, where malaria transmission occurs all year, booster doses will be given when children reach a specific age for example, 18 or 24 months. However, in the areas where malaria transmission is very seasonal, countries should consider giving booster doses just before the rainy season so as to get maximum impact,” said Greenwood.
Another study in Clinical Advances, Tanzania and UK researchers demonstrate that the candidate vaccine ChAd63-MVA RH5, whose safety and efficacy was unknown has now been declared safe. In a clinical trial in Tanzania, the researchers found that after vaccination, participants living in malaria-endemic areas developed immune responses.
