The Mosquirix vaccine, developed by British pharmaceutical giant GSK, has already been administered to more than 1.7 million children in three African countries - Ghana, Kenya and Malawi - as part of a pilot program.
In addition to these three test countries, which will continue to receive doses, nine other countries will benefit from supplies, WHO, UNICEF and the Vaccine Alliance (Gavi) said in a statement.
They are Benin, Burkina Faso, Burundi, Cameroon, the Democratic Republic of Congo, Liberia, Niger, Sierra Leone and Uganda.
"Malaria remains one of Africa's deadliest diseases, killing nearly half a million children under the age of five every year," WHO chief Tedros Adhanom Ghebreyesus told a briefing.
Tedros said a second malaria vaccine, the R21/Matrix-M developed by Oxford University and produced by the Serum Institute in India (SII), "is under review for pre-qualification" by the WHO, a procedure aimed at ensuring that health products to be supplied to low-income countries are safe and effective.
In 2021, 96% of the world's malaria deaths occurred in Africa.
"It's really important to remember nearly every minute a child dies of malaria ... (vaccines are) an additional tool in the toolbox to fight against the severe disease, the deaths that occur," said Kate O'Brien, director of the WHO's immunization and vaccines division.
Mgaywa Magafu, WHO vaccination official in Brazzaville, capital of the Republic of Congo, told VOA the number of countries that expressed interest was high.
"We have more than 28 countries on the continent that are interested at the moment in introducing the vaccine," Magafu said.
The WHO, UNICEF and Gavi estimate that the global demand for malaria vaccines is expected to reach 40-60 million doses annually by 2026 and then between 80-100 million doses annually by 2030.
UNICEF Immunizations Director Ephrem Lemango said the rollout is a major signal on the interest of countries to have more malaria vaccines, while encouraging "manufacturers and researchers to continuously innovate for new vaccines that will be able to have much higher impact."
Malaria, a disease transmitted to humans by the bites of certain types of mosquitoes, killed 619,000 people worldwide in 2021, according to the latest WHO figures.
Information for this report came from Agence France-Presse. VOA's Carol Van Dam contributed.