Re: What is the efficacy of the RTS,S malaria vaccine?
14 September 2012
Despite success in reducing the incidence of malaria over the last century, our current strategies may be weakening. This is for two main reasons: increasing resistance to artemisinins and the emergence of insecticide resistant mosquitoes. As a result, researchers have turned to try and find a vaccine with a new sense of urgency.
Early vaccine candidates failed to show significant protection against malaria. Initial results from the Mosquirix (RTS, S) trials are promising. The vaccine shows clear protection against natural P falciparum infection. However, protection is partial and short lived.
I think we will only see a measurable reduction in the burden of malaria if we use an integrated approach. We must continue to promote methods which we know are effective at preventing and treating malaria, potentially using a vaccine as an additional, rather than a replacement, tool.
It is the use of several control measures together has been key to the successful elimination of malaria in many countries. The WHO Global Programme for Malaria Eradication in 1955 relied on two strategies combined: the drug chloroquine for treatment of infected individuals and the chemical DDT for mosquito control. The programme is widely perceived to have been a failure, just because malaria was not eradicated worldwide. But in many ways, it was not a failure; elimination of malaria was achieved in over 30 countries and the risk of malaria was removed from about 20% of the world’s population.
A single strategy approach will not produce the best outcome. I argue that any successful reduction in the incidence of clinical malaria must adopt a multi strategy approach, from the provision of nets to ongoing research by pharmaceuticals to develop an effective vaccine. The multi strategy approach must take into account variation in the social and epidemiological characteristics of the community, and should be able to be implemented effectively in poor health systems.
Competing interests: None declared
University of Bristol, University of Bristol, Senate House, Tyndall Avenue, Bristol BS8 1TH, UK
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