World Health Organization (WHO), which released the results, said these gains were made over the last four years.
WHO said the RTSS vaccine also reduced by 22 per cent hospitalisation for severe clinical malaria in eligible children.
At least 28 African countries have now ordered millions of doses with the shipments beginning this week.
RTS,S has been tested in Kenya since early 2000.
It was then piloted in Kenya, Malawi and Ghana in 2019, leading to the WHO landmark decision to recommend it for wider use in October 2021.
The US $70 million pilot will be completed at the end of 2023 in the three countries.
The current results point to the potential of RTS,S and the similar R21/MatrixM malaria vaccine (under trial) to save “tens of thousands of lives each year” if broadly implemented, said Mary Hamel, WHO’s head of the Malaria Vaccine Implementation Programme, which coordinated the pilots.
Head of vaccine programmes for Gavi Stephen Sosler said the alliance has now approved funding for 18 countries to introduce the vaccine from 2024 onwards, and that at least 28 countries in Africa plan to introduce the vaccine.
On Wednesday, Gavi said more than 330,000 doses had been delivered in Cameroon.
Several other African countries are finalising rollout plans, and an additional 1.7 million doses are set for delivery to Burkina Faso, Liberia, Niger and Sierra Leone in the coming weeks, Gavi said.
Gavi said comprehensive preparations are needed to introduce any new vaccine into essential immunisation programmes – such as training of healthcare workers, investing in infrastructure, technical capacity, vaccine storage, community engagement and demand, and sequencing and integrating rollout alongside the delivery of other vaccines and health interventions.
“The world needs good news and this a good news story,” said David Marlow, CEO of Gavi, the Vaccine Alliance.
Unicef executive director Catherine Russell called it a gamechanger.
“Introducing vaccines is like adding a star player to the pitch. With this long-anticipated step, spearheaded by African leaders, we are entering a new era in immunisation and malaria control, hopefully saving the lives of hundreds of thousands of children every year,” she said.
“This is a significant advancement towards scaling up malaria vaccination in the region. The vaccine, which protects children from the severe forms of the disease, is a vital addition to the existing set of malaria prevention tools and will help bolster our efforts to reverse the rising trend in cases and further reduce deaths,” said Dr Matshidiso Moeti, WHO regional director for Africa.
A more powerful malaria vaccine, called R21, also partly tested in Kenya, is currently under review by WHO for prequalification.
The availability of two malaria vaccines is expected to increase supply to meet the high demand from African countries and result in sufficient vaccine doses to benefit all children living in areas where malaria is a public health risk, Gavi said.
“In preparation for scaled-up vaccination, Gavi, WHO, UNICEF and partners are working with countries that have expressed interest and/or have confirmed rollout plans on the next steps,” the alliance said in a statement.
