The R21/MM, the new malaria vaccine that researchers tried in Nanoro, Burkina Faso, has an efficacy of 77% in children aged 5-17 months – after receiving three 4-week interval doses before the malaria season, with a fourth dose arriving one year later. We have all the reasons for euphoria and ecstasy.
Controlling malaria has become an excruciating enigma for a disease that still ranks high up among the top ten causes of death in low- and lower-middle-income countries. Malaria causes significant morbidity and mortality among children under five years, as well as pregnant women. Malaria chemoprevention, residual spraying, and long-acting insecticide-treated mosquito nets have substantially reduced mortality and morbidity due to Plasmodium falciparum malaria – the vaccine remains the only feasible strategy for the elimination of malaria by 2030.
Currently, the only malaria vaccine ever tried is the RTS, S/AS01 that showed an efficacy of 55.8% over one year in African children. Yet, the World Health Organisation recommends that for any malaria vaccine to be effective, it should have an efficacy of 75% and above.
In the Nanoro, Burkina Faso trial, MS Datoo et al. randomised 450 children to receive the R21/MM vaccine or a Rabies vaccine as the control. In the study, the children receiving the R21/MM vaccine tolerated it well. It is imperative to know that some children received a low dose version of the vaccine candidate while others received a high dose. However, in both groups, vaccine efficacy was very high at 74% and 77%, respectively. The vaccine induced potent immunity against malarial parasites 28 days after the third dose. A fourth dose one year later boosted the immunity further.
We note that Plasmodium falciparum is one of the most complex parasites that scientists have studied. Because it continues to kill cause high morbidity and mortality among children and pregnant women, any step towards curbing its spread and the deleterious effects that follow is highly welcome, however small it is. But this new malaria vaccine may not be just a step; it may be a great leap forward towards eliminating malaria by 2030. And we all look up to it to see if it lives up to its hype once researchers conduct trials in more diverse settings.