Women and children waiting for vaccination at an outreach clinic in Lilongwe, Malawi. Credit: PATH

The RTS,S/AS01 pilots were designed to learn more about the malaria vaccine in routine use. The pilots, coordinated by the World Health Organization (WHO) and led by the health ministries in Ghana, Kenya, and Malawi, were meant to deliver the vaccine between 2019 and 2023 in parts of the three countries through routine immunization.

The pilots confirmed the vaccine’s safety and showed that routine delivery is feasible. High vaccine uptake indicated strong community demand, and in areas where it has been deployed, malaria vaccination substantially reduced the incidence of life-threatening severe malaria, decreased child hospitalizations, and reduced child deaths.

The 2021 WHO recommendation for widespread use of RTS,S was informed by a range of RTS,S evidence, including findings from pilot rollout of the vaccine:

  • Feasible to deliver: Vaccine introduction is feasible, with good and equitable coverage of RTS,S seen through routine immunization systems.
  • Safe and effective: With millions of doses of the vaccine administered, the vaccine has been shown to be safe and effective.
  • Reaching the unreached: RTS,S increases equity in access to malaria prevention, reaching more than two-thirds of children in the participating areas who were not sleeping under a bed net. All three pilot countries had equitable coverage across socio-economic groups, regardless of gender, resulting in 90% of children benefiting from at least one preventive intervention. 
  • No negative impact on uptake of bed nets, other childhood vaccinations, or health-seeking behavior for febrile illness: In areas where the vaccine has been introduced, there has been no decrease in the use of insecticide-treated bed nets, uptake of other childhood vaccinations, or health seeking behavior for febrile illness.
  • High impact in real-life childhood vaccination settings: Introducing the vaccine has generated significant reduction in deadly severe malaria, even when introduced in areas where insecticide-treated bed nets are widely used, and where there is good access to diagnosis and treatment.
  • Highly cost-effective: Modelling estimates that the vaccine is cost effective in areas of moderate to high malaria transmission.