"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).