"The mosquito is one of the deadliest animals on the planet," declared two South African researchers in a recent Nature article. This tiny insect is responsible for spreading malaria, a disease that infected nearly 250 million people in 2022 and killed more than 600,000 of them. Most of the victims live in sub-Saharan Africa, with children under 5 years of age accounting for nearly 80 percent of all malaria deaths.
But what if mosquitoes could deliver not just the disease but the protection? In a groundbreaking proof-of-concept clinical trial, researchers in the Netherlands recruited mosquitoes to deliver an antimalaria vaccine with each bite. As The New England Journal of Medicine reported in November, the mosquitoes were infected with attenuated malaria parasites modified to die a week after multiplying in the livers of the trial subjects bitten by the mosquitoes. Allowing the parasites to proliferate briefly in liver cells, the researchers hoped, would induce a strong protective immune system response.
Remarkably, it worked—nearly 90 percent of the subjects later bitten by mosquitoes carrying the natural malaria parasite did not contract the disease. This initial immune response suggests that the protection offered will last longer than current vaccines.
