Towards Eradication of Malaria: Is the WHO's RTS,S/AS01 Vaccination Effective Enough?

BACKGROUND

Recent advances in mosquito eradication and antimalarial treatments have reduced the malaria burden only modestly. An effective malaria vaccine remains a high priority, but its development has several challenges. Among many potential candidates, the RTS,S/AS01 vaccine (Mosquirix) remains the leading candidate.

OBJECTIVE AND METHOD

This review aims to understand the advances in the RTS,S/AS01 vaccine, and future comments regarding the vaccine's effectiveness in malaria eradication. Literature review for the past five decades was performed searching PubMed, EMBASE Ovid, and Cochrane Library, with using the following search items: ("malaria" OR "WHO's malaria" OR "Plasmodium falciparum" OR "RTS,S" OR "RTS,S/AS01" OR "RTS,S/AS02" OR "pre-erythrocytic malaria" OR "circumsporozoite" OR "Mosquirix") AND ("vaccine" OR "vaccination").

RESULTS

RTS,S/AS01, a recombinant pre-erythrocytic vaccine containing surface-protein (circumsporozoite) antigen, is safe, well-tolerated, and immunogenic in children. Three doses, along with a booster, have a modest efficacy of about 36% in children (age 5-17 months) and about 26% in infants (age 6-12 weeks) against clinical malaria during a 48-month follow-up. However, the efficacy varies among population subgroups and with the parasite strain, it reduces without a booster and offers protection for a limited duration. Because of its potential cost-effectiveness and positive public health effect, the vaccine is being investigated in a pilot program for mortality benefits and broader deployment.

CONCLUSION

The RTS,S/AS01 vaccine prevents malaria; however, it should be considered another addition to the malaria-control program and not as an eradication tool because of its relatively low to modest efficacy.