In spite of years of effort, and worldwide investment of billions of dollars, malaria remains a terrible scourge, particularly in Sub-Saharan Africa. Preventive efforts such as treated bed nets and availability of safe effective treatment with Artemisinin have somewhat reduced the incidence of clinical disease and mortality. Most recent statistics from the World Health Organization, however, show an annual incidence of 225 million cases and 817,000 deaths, mainly in young African children. For years many experts have recognized that real reductions in incidence and mortality will require an effective vaccine, but up to now efforts have been stymied by the complex life cycle of the malaria parasite. Another factor that increases the urgency for vaccine development is the appearance of resistance to Artemisinin in rural areas of Southeast Asia. If that resistance pattern spreads, we will be deprived of the use our current first line treatment.
Preliminary results of the first successful large scale vaccine trial have just been released. The RTS.S vaccine shows a 55% protection rate against all malaria episodes in vaccinated African children, and a 35% reduction in cases of severe malaria. Although these results are preliminary, and the success rate is lower that what is achieved currently with vaccines for other diseases, these results are by far the most encouraging ever achieved for a malaria vaccine. An excellent New England Journal of Medicine editorial points out that the success of the vaccine will depend not only on efficacy and safety, but also “on ongoing efforts to make the vaccine widely available and affordable where it is most needed.”( 2)
1. RTS.S. Clinical Trials Partnership: First Results of Phase 3 Trial of RTS,S/ASO1 Malaria Vaccine in African Children. NEJM2011: 1056-65.
2. Rosenbaum, L. A New Tool for Malaria Prevention? A Malaria Vaccine with a Good Shot: NEM 2011 blogs.nejm.org.
Submitted by Roger Boe MD.