London — American scientists are developing a new vaccine against the killer disease malaria following research on children in Tanzania.
Tests on mice showed that the vaccine protects against the disease and those involved in the study hope that it will be safe and effective in humans.
In the trial with mice, the vaccine doubled the lifespan of the rodents infected with the Plasmodium parasites that cause malaria and reduced the number of parasites by three quarters.
According to the academic journal "Science", the breakthrough came when researchers looked at 785 children in Tanzania and found that six per cent of them had antibodies that protect against the disease.
In addition, the researchers from Rhode Island Hospital, the National Institutes of Health, Harvard Medical School, and the University of Washington found that the same antibodies were present in the blood of Kenyan teenagers who also had natural protection against the disease.
This led to the development of the primary vaccine PfSEA-1 which disrupts the life cycle of the Plasmodium parasites, trapping them inside red blood cells and preventing them from spreading.
The vaccine takes a new approach to tackling the disease. Other potential vaccines try to stop the parasites entering the red blood cells - an earlier stage of the Plasmodium life cycle.
One of the lead researchers, Jonathan Kurtis, explained that this mechanism would need to work in tandem with other vaccines aimed at other parts of the cycle. It does not eliminate the parasites but reduces them to a level that can ease the symptoms.
In the next phase, the researchers will move on to trials involving primates before clinical trials with humans.
Human trials of the most advanced malaria vaccine, RTS,S, partly carried out in Manhica in southern Mozambique, showed that it does offer protection against the disease. However, the vaccine only halved the number of malaria cases in young children (aged 5-17 months at first vaccination) and reduced by around a quarter malaria cases in infants (aged 6-12 weeks at first vaccination).
The World Health Organisation estimates that 627,000 people die from malaria each year. Most of those deaths are of children under the age of five living in sub-Saharan Africa.
Last year, Mozambican health units diagnosed a total of 3,924,832 cases of malaria and recorded 2,091 deaths from the disease.