Cameroon marked a significant step in the global battle against malaria on Monday by initiating the world's first routine vaccine program for the mosquito-borne disease. This groundbreaking effort is expected to save tens of thousands of children's lives annually across Africa.

Around 40 years in the making, the World Health Organization (WHO)-approved RTS,S vaccine developed by British drugmaker GSK is meant to work alongside existing tools such as bed nets to combat malaria, which in Africa kills nearly half a million children under the age of 5 each year.

After successful trials, including in Ghana and Kenya, Cameroon is the first country to administer doses through a routine immunization program that 19 other countries aim to roll out this year, according to global vaccine alliance Gavi.

Around 6.6 million children in these countries are targeted for malaria vaccination through 2024-25.

"For a long time, we have been waiting for a day like this," said Mohammed Abdulaziz of the Africa Centres for Disease Control and Prevention (CDC) at a joint online briefing with the WHO, Gavi and other organizations.

The urgency is clear. Disruptions linked to the COVID-19 pandemic, rising insecticide resistance and other issues have hindered the fight against malaria in recent years with cases rising by around 5 million year-over-year in 2022, according to the WHO.

Overall, more than 30 countries on the continent have expressed interest in introducing the vaccine and fears of a supply squeeze have eased since a second vaccine completed a key regulatory step in December.

Rolling out the second vaccine "is expected to result in sufficient vaccine supply to meet the high demand and reach millions more children," the WHO's director of immunization, Kate O'Brien, said at the briefing.

This R21 vaccine, developed by the University of Oxford, could be launched in May or June, said Gavi's Chief Program Officer Aurelia Nguyen.

Some experts have expressed skepticism, saying attention and funding should not be drawn away from the wider fight against the age-old killer and the use of established malaria-prevention tools like bed nets.

Health experts at the briefing said the roll-out was accompanied by extensive community outreach to combat any vaccine hesitancy and to emphasize the importance of continuing to use all protective measures alongside the vaccines.