After 50 years of failure, a vaccine against malaria could be in sight, raising hopes of slashing the death toll from a disease that kills more than a million people, mostly babies and pregnant women, every year.
For the first time, human trials carried out on more than 2 000 young children in Africa have shown that it is possible to produce a vaccine that will protect some infants against infection and make the course of the disease less serious and life-threatening in others.
Results from the trials in Mozambique are published today in The Lancet medical journal.
Pedro Alonso, from the centre of international health at the University of Barcelona, and the team who carried out the research say that, although the vaccine gave the children only partial protection from disease, the results ”show development of an effective vaccine against malaria is feasible”.
The trial involved 2 022 children aged between one and four living in southern Mozambique, where each person gets an estimated 38 bites a year from malarial mosquitoes.
The researchers found that vaccinated children were 30% less likely to have suffered at least one episode of clinical malaria (that needed treatment) by the end of the six-month trial, compared with unvaccinated children.
The vaccine was 45% successful in extending the length of time before children became infected with malaria, and vaccinated children were 58% less likely to develop severe malaria which could kill them.
There was a mixture of excitement and restraint from the scientists involved, who say that the earliest a vaccine could be licensed, if further trials go well, is 2010.
”These results demonstrate the feasibility of developing an efficacious vaccine against malaria that could significantly contribute to reduce the intolerable global burden of this disease,” writes Dr Alonso in The Lancet.
The progress owes much to the malaria vaccine initiative (MVI), which was set up with a grant from the Bill and Melinda Gates Foundation. The MVI promotes public-private partnerships, often in areas that lack profitability, such as supplying medicines to the developing world.
The vaccine, known as RTS,S/AS02A, was discovered by GlaxoSmithKline Biologicals and is one of a number of possible vaccines that have been given financial backing by the MVI.
Melinda Moree, the director of the MVI, was enthusiastic about the trial results.
”These findings represent a breakthrough in the science of malaria vaccines. They provide convincing evidence that a vaccine could become part of the world’s efforts to spare children and families from the devastating effects of this disease. This brings us another step closer to a licensed vaccine,” she said.
It has taken a long time to get this far. Other vaccines — most notably one called SPf66, developed by the Colombian scientist Manuel Patarroyo — have seemed promising but ended in disappointment.
SPf66 looked good in the laboratory and in animal tests, but human trials, first in Gambia and Tanzania, backed by the World Health Organisation, and then in Thailand, supported by the United States military, showed no protection against the disease.
In a commentary on the latest results, also published in The Lancet, Philippe van de Perre and Jean-Pierre Dedet, from the University of Montpellier in France, say there is no reason to think things will now get easier.
”The road toward a safe and efficient malaria vaccine being available and usable on a large scale … will be long and chaotic,” they write.
It is fundamentally important to carry on because of the worsening nature of the malaria epidemic. Commonly used drug treatments have become useless in some parts of the world because malaria parasites have developed resistance to them.
The HIV/Aids epidemic is also weakening the immune systems of many people in malarial areas, making them less able to fight the disease.
”More than ever, infants, young children and pregnant women, who are heavily affected by the direct and indirect consequences of malaria in endemic areas, deserve worldwide scientific, political and financial commitment,” the scientists write.
”Such commitment is a question of equity, of human rights and of disease exposure for half the inhabitants of our planet.” – Guardian Unlimited Â