Malaria has been a serious issue since a long period of time and controlling malaria has been a top goal of international public-health authorities. Caused by parasites transmitted by infected mosquitoes, malaria annually sickens more than 200 million people and kills nearly 800,000, mostly children in Africa. Because children are the most vulnerable to the disease, efforts to develop a vaccine have focused on them.
Globally, deaths from malaria apparently declined from around 1 million in 2000 to less than 800,000 in 2009. How have we gotten this far? The world has committed to expanding use of insecticide-treated bed nets, artemisinin-based combination therapies, and indoor residual spraying. We should further expand the use of these measures as the burden of the disease is still too high. But even this may not be enough.
For decades, global health experts believed that it was impossible to immunize against infection caused by malarial parasite. And the death and disabilities continued to haunt the poor nations of Africa, Asia and Latin America for all these years. A malaria vaccine has eluded scientists for decades, but preliminary results from a phase 3 clinical trial in Africa are providing hope. The data suggest that the vaccine, known as RTS S reduces the number of cases to half.
The Phase 3 clinical trial was conducted among 6,000 sub-Saharan African children five to 17 months old who were given three doses. The vaccine is designed to prevent the malaria parasite from infecting, maturing and multiplying in the liver and re -entering the bloodstream. The vaccine is designed specifically for children because their immune systems are still developing, making them the easiest prey for the parasitic disease. Youngsters under the age of 5 account for the vast majority of the 800,000 people who die of the condition each year.
The results of a phase III trial of the drug candidate, RTS, S published in New England Journal of Medicine show that the malaria vaccine candidate provided significant protection against clinical and severe malaria with an acceptable safety and tolerability profile. The vaccine is being developed by GSK and the PATH Malaria Vaccine Initiative (MVI), together with prominent African research centers. The partners are all represented on the Clinical Trials Partnership Committee which is conducting the trial. Major funding for clinical development is from a grant by Bill & Melinda Gates Foundation to MVI. The trial, conducted at 11 trial sites in seven countries in sub-Saharan Africa, showed that three doses of RTS, S reduced the risk of children experiencing clinical malaria and severe malaria by 56% and 47%, respectively. This conclusion was based on the data from 6,000 children aged 5 to 17 months, over a 12-month period of vaccination.
The Phase III trial is well on its way, having recently completed the enrollment of more than 15,000 infants and children. Preliminary results for the 5–17-month-old group are expected later this year, and in late 2012 the researchers hope to have initial results for the 6–12-week-old group. The final analysis is expected in late 2014. as the adverse events of the vaccine need to be regularly monitored and the total safety profile of RTS,S has to be evaluated.