A transmission-blocking vaccine is designed to prevent mosquitoes carrying malaria parasites from spreading them.

Transmission-blocking vaccines (TBV) would break the life cycle of the parasite by preventing mosquitoes from becoming infected by malaria-causing parasites when they feed on infected people. They would do this by inducing antibodies that prevent the parasite from maturing in the mosquito after it takes a blood meal from a vaccinated person.   

While the TBV approach would not necessarily prevent malaria infection in the immunized person, such a vaccine would reduce the number of mosquitoes carrying the parasite and thus the number of people in a community who are infected. A successful TBV, deployed widely among those responsible for maintaining local parasite transmission, would be expected to reduce deaths and illness related to malaria in at-risk communities.  

Blocking transmission of malaria parasites is viewed as particularly important to malaria elimination and eradication efforts, including prevention of reintroduction of the parasite into communities. When used in conjunction with other malaria control tools, a vaccine able to protect the individual—and the mosquito—from parasite transmission could help push a geographic region past the threshold of control to elimination and, ultimately, accelerate eradication.