The “dramatic” results, published in the New England Journal
of Medicine on Wednesday, came from combining booster shots of an antimalarial
vaccine ahead of the rainy season together with preventative drugs.
Malaria kills more than 400,000 people a year, the vast
majority under the age of five.
The paper’s senior author Brian Greenwood of the London
School of Hygiene and Tropical Medicine told AFP that members of the team were
in touch with the World Health Organization about updating its recommendations.
The RTS,S vaccine, made by British pharmaceutical company
GSK, was developed more than 20 years ago but by itself is not highly
effective, said Greenwood.
Prior research has shown the vaccine’s protection wanes over
time and it offers around 30 percent efficacy over a period of three to four
years.
Since malaria is highly seasonal in the Sahel and sub-Sahel
region, the team wanted to test whether giving boosters before each year’s rainy
season, when mosquito populations peak, would improve outcomes.
The trial followed around 6,000 children aged five to 17
months from Burkina Faso and Mali over the course of three years.
The children were split into three groups: those who
received only the anti-malarial drugs sulfadoxine–pyrimethamine and
amodiaquine; those who received only the RTS,S vaccine; and those who received
a combination.
The combination was the most effective intervention,
reducing malaria cases by 63 percent, hospitalizations by 71 percent, and
deaths by 73 percent compared to the drugs alone.
“That was pretty dramatic,” said Greenwood — stressing that
these numbers are on top of the impact of the already effective drugs, not
compared to no medicine, which would have been unethical to test.
He estimated that the combination of the booster vaccine
doses and antimalarial drugs reduced hospitalizations and deaths by 90 percent
compared to no intervention.
Children initially receive three doses of the vaccine to
prime their systems, then a booster every year. It is based on a particle that
trains the immune system against the Plasmodium falciparum parasite.
The anti-malarial drugs are given for three days a month
every four months.
Greenwood said the study showed the value of developing
plans in accordance with local epidemiological conditions — in this case
administering vaccines ahead of peak season, instead of during times when there
was no transmission and their impact would fade.
“Like a lot of these things it’s sort of common sense but
nobody has actually put this into practice, to see whether it actually would
work,” he said.
“Hopefully this may get implemented in several countries and
save lots of people’s lives.”
AFP
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