Blood-stage Vaccine for malaria shows promise in trials

NEW DELHI: A novel malaria vaccine candidate that works at the blood stage appears safe and highly immunogenic in African children and shows promising efficacy against malaria when given in a delayed third dose regimen, according to the findings of a phase 2b clinical trial published in The Lancet Infectious Diseases on Tuesday.

- Rhythma Kaul

Work is ongoing to further monitor efficacy over time, the researchers said in the paper about the vaccine candidate that has been named RH5.1/Matrix-M.

Malaria, caused by plasmodium falciparum parasites, is a leading cause of death in children under five in many parts of Africa. Blood-stage malaria — when the parasite infects red blood cells — causes symptoms of the disease like fever and chills, and can lead to severe, life-threatening complications like anaemia and organ failure.

The two malaria vaccines approved currently (RTS,S/AS01 and R21/Matrix-M) target the malaria parasite when present in the liver and are now recommended for malaria prevention in children. However, the new vaccine is different in the sense that it targets the malaria parasite when it is present in the blood, therefore providing a second line of defence. The previous two vaccines do not induce blood-stage immunity against malaria parasites that can breakthrough from the liver into the blood, experts said.