The World Health Organization on Wednesday endorsed the first ever vaccine to prevent malaria in what many experts predicted could save the lives of thousands of African children.

Malaria, which is known to be among the oldest known and deadliest of infectious diseases, 500,000 people each year in sub-Saharan Africa, with about half of them children under age 5.

Produced by pharmaceutical giant, GlaxoSmithKline, the new vaccine reportedly rouses a child’s immune system to thwart Plasmodium falciparum, the deadliest of five malaria pathogens and the most prevalent in Africa.

The New York Times reported that the vaccine is not just a first for malaria — it is the first developed for any parasitic disease.

Christened ‘Mosquirix,’ the new vaccine is given in three doses between ages 5 and 17 months, and a fourth dose roughly 18 months later.

Following clinical trials, the vaccine was tried out in three countries — Kenya, Malawi and Ghana — where it was incorporated into routine immunization programs.

More than 2.3 million doses have been administered in those countries, reaching more than 800,000 children.

That bumped up the percentage of children protected against malaria in some way to more than 90 percent from less than 70 percent.

This week, a working group of independent experts in malaria, child health epidemiology and statistics, as well as the W.H.O.’s vaccine advisory group, met to review data from the pilot programs and make their formal recommendation to Dr. Tedros Adhanom Ghebreyesus, director-general of the W.H.O.

The next step is for Gavi, the global vaccine alliance, to determine that the vaccine is a worthwhile investment. If the organization’s board approves the vaccine — not guaranteed, given the vaccine’s moderate efficacy and the many competing priorities — Gavi will purchase the vaccine for countries that request it, a process that is expected to take at least a year.

But as with Covid-19, problems with vaccine production and supply could considerably delay progress. And the pandemic has also diverted resources and attention from other diseases, said Deepali Patel, who leads malaria vaccine programs at Gavi.

“Covid is a big unknown in the room in terms of where capacity is currently in countries, and rolling out Covid-19 vaccines is a huge effort,” Ms. Patel said. “We’re really going to have to see how the pandemic unfolds next year in terms of when countries will be ready to pick up all of these other priorities.”