Vaccine shows promise against malaria.

Colombian scientists have scored a victory in the never ending war against malaria. They used a vaccine called SPf66, which combines protein fragments from several stages of a malaria-causing parasite's life cycle. Over a 6-month period, 1,540 volunteers from Colombia's southern Pacific Coast took three doses of the experimental vaccine or a placebo. For the next year, researchers monitored how often the volunteers suffered a bout of malaria. Neither the participants nor the clinics treating them knew who was taking the real vaccine.

The two groups of people suffered equally from malaria caused by Plastnodiurn vivax, but the vaccine did decrease the number of cases caused by Plasrnodium falciparutn by about 40 percent, says M.V. Valero of the National University of Colombia in Bogota. Of the 738 volunteers who received the vaccine, 152 developed P. falciparum malaria at least once, for a total of 168 episodes. But 242 of the 819 people taking the dummy drug came down with a total of 297 cases of this more common malarial infection. The results indicate that the vaccine works best after one bout of malaria and in children under age 5 and adults older than 45, Valero and his colleagues report in the March 20 LANCET.

Ivars Peterson reports from Seattle at an American Physical Society meeting