(CNN) Some 360,000 children a year in three African countries will receive the world's first malaria vaccine as part of a large-scale pilot project, the World Health Organization said Tuesday.

Malawi has started vaccinating children under 2 years of age, and Kenya and Ghana will begin using the vaccine in the coming weeks, with health ministries in these countries deciding where it will be used, WHO said.

Malaria vaccine pilot launched in Malawi

The vaccine offers partial protection from the disease, with clinical trials finding that it prevented approximately 4 in 10 malaria cases, according to WHO.

"We have seen tremendous gains from bed nets and other measures to control malaria in the last 15 years, but progress has stalled and even reversed in some areas. We need new solutions to get the malaria response back on track, and this vaccine gives us a promising tool to get there," WHO Director-General Dr. Tedros Adhanom Ghebreyesus said in a statement.

"The malaria vaccine has the potential to save tens of thousands of children's lives."