R21/Matrix-M vaccine well-tolerated and efficacious against malaria in children

A recent study found that R21/Matrix-M vaccine which is low-cost, was well tolerated and offered high efficacy against clinical malaria in children. The results of this study were published in the journal, Lancet.

This double-blind, randomised, phase 3 trial of the R21/Matrix-M malaria vaccine screened 5477 children (aged 5-36 months), out of which 1705 and 3434 children were randomly assigned in a 2:1 ratio to the control vaccine and R21/Matrix-M (5 μg R21 plus 50 μg Matrix-M), respectively. The vaccines were administered 4 weeks apart as 3 doses, with a booster dose administered 12 months after the third dose. Half of the participants were recruited at the seasonal malaria transmission sites and the other half at standard sites with perennial malaria transmission. The primary objective of the study was to assess the protective efficacy of R21/Matrix-M, 14 days following the third vaccination. Vaccine efficacy, safety, and immunogenicity were also assessed.

At the end of the study, it was found that R21/Matrix-M vaccine was well tolerated. The most frequent adverse events were injection site pain (301 out of 1615 participants) and fever (754 out of 1615 participants). At the end of 12 months, the vaccine efficacy at the seasonal sites and standard sites were 75% and 67%, respectively. The effectiveness of the vaccine was correlated with antibodies produced by the vaccination against the conserved central Asn-Ala-Asn-Pro (NANP) repeat sequence of the circumsporozoite protein. The 5-17 month age group of children showed higher NANP-specific antibody titres when compared to the 18-36 month age group.

From the above results, it can be concluded that R21/Matrix-M vaccine which is low-cost, may be well tolerated and may offer high efficacy against clinical malaria in children.