Malaria vaccine passes ‘critical milestone’

Researchers have claimed that a malaria vaccine that uses a genetically weakened form of the parasite has passed a ‘critical milestone’ in human safety trials.

Published in the Science Translational Medicine journal, the trials food that the modified form of malaria was unable to cause a full infection in people, leading to ‘promising’ suggestions that it was safe.

The trials infected 10 people with the weakened parasite, deliberately exposing the immune system to malaria. However, the parasite is unable to complete its lifecycle to cause disease. None of the 10 people went on to develop the disease, and no severe side-effects to the treatment were recognised.

The researchers at Seattle’s Centre for Infectious Disease Research deleted three genes from the parasite so that it could not infect liver cells. Other approaches involve weakening the malaria parasite by exposing it to radiation or giving the patient anti-malarial drugs at the same time as infecting them.

Dr Sebastian Mikolajczak, one of the researchers, said: "The clinical study now shows that the vaccine is completely attenuated in humans and also shows that even after only a single administration, it elicits a robust immune response against the malaria parasite. Together these findings are critical milestones for malaria vaccine development."

Sir Brian Greenwood, from the London School of Hygiene and Tropical Medicine, told the BBC News website: "It is encouraging, but this is a first step toward developing a vaccine. It is really promising and the evidence presented here is enough for challenge studies [in which people are immunised and then infected with malaria to see if it works]."