An international group of researchers estimates that, despite only moderate uptake of three doses and low uptake of the fourth, the RTS,S/AS01E malaria vaccine saved the lives of one in eight eligible children in the first three African nations to offer the vaccine from 2019 to 2023.
For the observational study, published late last week in The Lancet, the research team randomly assigned 158 administrative-unit clusters, each with a birth cohort of roughly 4,000 children, in Ghana, Kenya, and Malawi to either roll out the RTS,S malaria vaccine in 2019 (79 implementation areas) or to implement it later (79 comparison [control] areas).
Doses of RTS,S vaccine were given at ages 6, 7, 9, and 24 months in Ghana and Kenya and at ages 5, 6, 7, and 22 months in Malawi. A network of 26,000 local people were responsible for reporting deaths from any cause except injury in children younger than 5 years. Study staff followed up the death reports with a home visit to confirm details and complete a “verbal autopsy.”
Eighteen sentinel hospitals in part of the study area conducted strengthened surveillance for severe malaria and other conditions for 46 months. The Expanded Programme on Immunisation in each country monitored uptake of RTS,S and other vaccines, and vaccine-coverage surveys were fielded to households at baseline and 18 and 30 months after RTS,S became available.
The authors estimated mortality rate ratios by comparing the ratio of deaths in vaccine-eligible age-groups to deaths in ineligible age-groups in implementation and comparison areas.
Favorable evidence on the vaccine’s safety and impact on severe malaria during the first two years of the study contributed to World Health Organization’s (WHO's) recommendations on malaria vaccines for children.
“Malaria vaccines have been added to immunisation schedules in 25 sub-Saharan African countries, with the expectation that deaths in young children would be prevented,” they noted. “Two malaria vaccines, RTS,S/AS01 and R21/Matrix-M, have been recommended by WHO for the prevention of Plasmodium falciparum malaria in children, prioritising areas of moderate and high malaria transmission.”
Death rate drops 13%
Uptake in 2022 was 82.8% for the first dose, 71.1% for the third dose, and 39.9% for the fourth dose. By 46 months, nearly 1.3 million children had received the first dose of RTS,S, while 1.2 million had gotten the second dose, 1.1 million were given a third dose, and 436,527 had received a fourth dose.
The vaccine was estimated to have prevented one in eight child deaths in eligible children—a 13.2% reduction in death.
