Malaria vaccine shows promise in Mozambique
Nathan Seppa
An experimental vaccine offers some protection against malaria, a new large-scale study finds.
Researchers gave injections to 1,605 children of ages 1 to 4 years in rural Mozambique. Half received three doses of a malaria vaccine being tested by GlaxoSmithKline Biologicals, plus shots of hepatitis B vaccine. The other half got three injections combining vaccines for hepatitis B and meningitis.
After 6 months, the researchers were able to assess 1,380 of these children, almost evenly split between the two study groups. The scientists found that 123 of the children who had received the malaria vaccine and 159 of those who had gotten the other shots had had an episode of malaria marked by fever, illness, and a blood test confirming the presence of the protozoan Plasmodium falciparum. The episodes in 11 of the malaria-vaccinated children and in 26 of the others were judged to have been severe. The results show that the new vaccine offers significant protection against contracting malaria, particularly life-threatening malarial episodes, the researchers report in the Oct. 16 Lancet.
The experimental malaria vaccine tested in Mozambique generates antibodies against a protein that coats P. falciparum when it's in its sporozoite stage, immediately after a mosquito injects the parasite into a victim. The antibodies intercept the sporozoite before it can infect liver cells, says study coauthor W. Ripley Ballou, a physician researcher with GlaxoSmithKline in Rixensart, Belgium.
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References:
Alonso, P.L. … W.R. Ballou, et al. 2004. Efficacy of the RTS,S/AS02A vaccine against Plasmodium falciparum infection and disease in young African children: Randomised controlled trial. Lancet 364(Oct. 16):1411–1420. Available at http://dx.doi.org/10.1016/S0140-6736(04)17223-1.
Further Readings:
Ballou, W.R., et al. 2004. Update on the clinical development of candidate malaria vaccines. American Journal of Tropical Medicine and Hygiene 71(August):239–247. Available at http://www.ajtmh.org/cgi/content/full/71/2_suppl/239.
Bojang, K.A. … W.R. Ballou, et al. 2001. Efficacy of RTS,S/AS02 malaria vaccine against Plasmodium falciparum infection in semi-immune adult men in The Gambia: A randomised trial. Lancet 358(Dec. 8):1927–1934. Available at http://dx.doi.org/10.1016/S0140-6736(01)06957-4.
Klausner, R., and P. Alonso. 2004. An attack on all fronts. Nature 430(Aug. 19)):930–931. Available at http://dx.doi.org/10.1038/430930a.
Nussenzweig, R.S., and F. Zavala. 1997. A malaria vaccine based on a sporozoite antigen. New England Journal of Medicine 336(Jan. 9):128–130. Extract available at http://content.nejm.org/cgi/content/extract/336/2/128.
Van de Perre, P., and J.-P. Dedet. 2004. Vaccine efficacy: Winning a battle (not war) against malaria. Lancet 364(Oct. 16):1380–1382. Available at http://dx.doi.org/10.1016/S0140-6736(04)17235-8.
Sources:
W. Ripley Ballou
GlaxoSmithKline Biologicals
Rue de L'Institut 89
Rizensart, 1330
Belgium
From Science News, Volume 166, No. 19, November 6, 2004, p. 301.
