By combining vaccination, chemoprevention dramatically reduces malaria

A combination of seasonal vaccination and chemoprevention reduced malaria episodes and deaths in children by about 70% compared to either intervention alone in a 3-year study in two African countries , the researchers reported.

The vaccine, RTS, S / AS01_E (GlaxoSmithKline), was the first vaccine ever shown to significantly reduce malaria in children. It is administered through a pilot program in three African countries: Ghana, Kenya and Malawi.

The results of the study published this week in The New England Journal of Medicine are the result of a study conducted from 2017 to 2020 in Burkina Faso and Mali.

Daniel Chandramohan,

“The burden of severe malaria continues to be high in countries where seasonal malaria chemoprevention is implemented, so it is clear that we need an effective intervention in addition to seasonal malaria chemoprevention.” Daniel Chandramohan, MBBS, PhD, MSc, a professor of public health at the London School of Hygiene and Tropical Medicine, told Healio.

“The RTS, S malaria vaccine has been shown to have good protective efficacy for at least the first 6 months after vaccination,” said Chandramohan. “This prompted our study to test the hypothesis that a combination of seasonal malaria vaccination with preventive chemotherapy will reduce the burden of malaria in this region.”

Chandramohan and colleagues performed an individually randomized controlled trial to assess whether seasonal vaccination with RTS, S given with adjuvant AS01_E was not inferior to chemoprevention in the prevention of uncomplicated malaria and whether the interventions used together were superior to either used alone in the prevention of uncomplicated malaria and severe malaria-related outcomes.

According to the study, from April to May 2017, researchers randomly assigned 6,861 children aged 5 to 17 months to receive seasonal chemoprevention with sulfadoxine-pyrimethamine and amodiaquine alone (n = 2,287) , the vaccine alone (n = 2,288), and 2,286 to receive a combination of the two.

A total of 1,716 children in the chemoprevention-only group, 1,734 in the vaccine-only group, and 1,740 in the combination group received their first dose of treatment and completed follow-up until May 31, 2020.

In total, there were 305 uncomplicated clinical malaria events per 1,000 person-years at risk in the chemoprevention-only group, 278 in the vaccine-only group, and 113 in the combination group, the researchers reported. The calculated protective efficacy of the combination compared to chemoprevention alone was 62.8% (95% CI, 58.4-66.8) against clinical malaria, 70.5% (95% CI, 41, 9-85) against hospitalization for severe malaria according to the WHO definition, and 72.9% (95% CI, 2.9-92.4) against deaths due to malaria.

They calculated that the protective efficacy of the combination compared to the vaccine alone against these results was 59.6% (95% CI, 54.7-64), 70.6% (95% CI, 42, 3-85) and 75.3% (95% CI, 12.5-93), respectively.

Ashley Birkett, Doctorate, director of PATH’s Malaria Vaccine Initiative, described the results as “remarkable.” PATH provided some funding for the study.

“This represents a potential breakthrough in how the world’s first malaria vaccine could be used in new ways to save children’s lives,” Birkett said in a press release. “Evidence from Burkina Faso and Mali suggests that in areas with very seasonal malaria, the use of RTS, S vaccine just before the peak transmission season in combination with current malaria control interventions, could have an impact. major. “