A new vaccine for malaria is up to 100 per cent effective when assessed at 10 weeks after last dose, according to the results of a clinical trial.
The vaccine called Sanaria PfSPZ-CVac incorporated fully viable - not weakened or otherwise inactivated - malaria pathogens together with the medication to combat them.
Malaria parasites are transmitted by the bite of female Anopheles mosquitoes.
The Plasmodium falciparum parasite is responsible for most malaria infections and almost all deaths caused by the disease worldwide.
Most of the previous vaccines which have been tried involved the use of individual molecules found in the pathogen. However, they were unable to provide sufficient immunity to the disease.
The study by University of Tubingen in Germany in collaboration with the biotech company Sanaria involved 67 healthy adult test persons, none of whom had previously had malaria.
The best immune response was shown in a group of nine test persons who received the highest dose of the vaccine three times at four-week intervals.
At the end of the trial, all nine of these individuals had 100 per cent protection from the disease.
"That protection was probably caused by specific T-lymphocytes and antibody responses to the parasites in the liver," said Professor Peter Kremsner.
The researchers analysed the bodies' immune reactions and identified protein patterns which will make it possible to further improve malaria vaccines, Kremsner added.
They injected live malaria parasites into the test subjects, at the same time preventing the development of the disease by adding chloroquine - which has been used to treat malaria for many years.
This enabled the researchers to exploit the behaviour of the parasites and the properties of chloroquine.
Once the person is infected, the Plasmodium falciparum parasite migrates to the liver to reproduce.
Malaria only breaks out when the pathogen leaves the liver, entering the bloodstream and going into the red corpuscles, where it continues to reproduce and spread.
As soon as the pathogen enters the bloodstream, however, it can be killed by chloroquine - and the disease cannot break out.
"By vaccinating with a live, fully active pathogen, it seems clear that we were able to set of a very strong immune response," said study leader Benjamin Mordmueller.
"Additionally, all the data we have so far indicate that what we have here is relatively stable, long-lasting protection," said Mordmueller.
In the group of test persons who demonstrated 100 per cent protection after receiving a high dose three times, Mordmueller said, the protection was reliably still in place after ten weeks - and remained measurable for even longer.
The research was published in the journal Nature.