This is a double-blind randomized controlled clinical trial to evaluate the efficacy of R21 adjuvanted with Matrix-M in healthy 5-17 month old children in a malaria-endemic area.
There are two study vaccines: the IMP, R21 adjuvanted with Matrix-M; and Rabies Vaccine. Group 1 (active vaccine group) participants will receive 3 vaccinations of R21 5μg with 25μg Matrix-M, 4 weeks apart via the intramuscular route, and a booster vaccination one year following the third vaccination.
Group 2 (active vaccine group) participants will receive 3 vaccinations of R21 5μg with 50μg Matrix-M, 4 weeks apart via the intramuscular route, and a booster vaccination one year following the third vaccination.
Group 3 (control group) participants will receive three vaccinations with rabies vaccine, four weeks apart, all given intramuscularly and a fourth vaccination with rabies vaccine one year following the third vaccination.
450 children were randomized to receive the R21/MM vaccine or a control rabies vaccine. R21/MM had a 43 favorable safety profile and was well-tolerated. At 6 months, 43/146 (29·5%) who received R21/MM with low44 dose adjuvant, 38/146 (26%) who received R21/MM with high-dose adjuvant, and 105/147 (71·4%) who received the rabies vaccine developed clinical malaria.
Vaccine efficacy (VE) was 74% (95% CI, 63-82) and 77% (95% CI, 67-84) in the low- and high-dose adjuvant groups, respectively.
At 1 year, VE remained high at 77% (95% CI, 67-84) in the high-dose adjuvant group. Participants vaccinated with R21/MM showed high titers of malaria-specific anti-NANP antibodies 28 days after the third vaccination, which were almost doubled with the higher adjuvant dose.
Titres waned but were boosted to levels similar to peak titers following the primary series of vaccinations after a fourth dose was administered one year later.