More bad news for malaria vaccine

The protection provided by the world’s first malaria vaccine all but disappears after seven years, according to a new study. A phase-two clinical trial of Mosquirix (RTS,S) in Kenya showed just 4 percent effectiveness in children older than 7 years. With an already relatively low rate of malaria prevention, this is another setback for GlaxoSmithKline, the developer of the vaccine. “The reduced exposure to blood-stage parasites among persons who have received the RTS,S/AS01 vaccine may lead to a slower acquisition of immunity to blood-stage parasites, leading to an increase in episodes of clinical malaria in later life,” according to the study, published in the New England Journal of Medicine. More than 440 children were tracked over seven years. Half of the children received three doses of the vaccine and half did not get it at all. In the first year, vaccinated children were 35.9 percent less likely to get malaria compared to...