Effectiveness of candidate malaria vaccine decreases over time, study shows

Mar 22 2013

"The effectiveness of an experimental malaria vaccine developed by GlaxoSmithKline wanes over time, with the shot protecting only 16.8 percent of children over four years, according to trial data," Reuters reports. "The disappointing results for RTS,S -- the world's first potential malaria vaccine -- raise further questions about whether it can make a difference in the fight against the disease, a major cause of illness and death among children in sub-Saharan Africa," the news service adds (Kelland/Emery, 3/20). "Scientists point out that they will need to see the full results, from large-scale trials of thousands of children, before they really know how useful the vaccine ... will be," the Guardian writes. "But the tests follow a string of disappointing results, which have clearly shown how difficult it is to make a vaccine to protect against the disease, which kills more than 650,000 children, most of them very young, a year," the newspaper notes (Boseley, 3/20).

"The vaccine 'is the only one ever to be tested in a phase III clinical trial,'" ScienceNow writes, noting, "That trial reported promising initial results in 2011, cutting rates of malaria by half in toddlers. But findings published in November clouded its prospects, as the vaccine failed to protect young babies as much as hoped" (Vogel, 3/20). "The latest findings, published in the New England Journal of Medicine, come from a smaller phase II trial that began in 2009 and was designed to assess safety and efficacy ahead of the large-scale phase III trials," the Guardian adds (3/20). The study, led by KEMRI-Wellcome Trust Research Program and Oxford University researchers in Kenya, "involved 447 children in Kilifi, Kenya, who had been part of an earlier phase II trial to assess the safety and efficacy of the vaccine candidate," according to a Wellcome Trust press release (3/20).