A booster dose of a new
malaria vaccine maintains a high level of protection
against the disease, researchers said Thursday, expressing hopes the cheap jab
could be produced on a massive scale in a matter of years.
اضافة اعلان
The international research team suggested the vaccine, developed by
Britain's Oxford University, could represent a turning point in the fight
against the mosquito-borne parasitic disease, which killed 627,000 people --
mostly African children -- in 2020 alone.
Last year a different vaccine produced by British pharmaceutical giant GSK
became the first to be recommended for widespread use against malaria by the
World Health Organization, and has now been administered to more than a million
children in Africa.
However research has found that the effectiveness of GSK's vaccine is around
60 percent, and significantly wanes over time even with a booster dose.
Oxford's R21/Matrix-M vaccine meanwhile was found to be 77 percent effective
at preventing malaria in research published last year -- the first time the
WHO's roadmap goal of 75 percent had been met.
- 'Fantastic'
-
For the research, 450 children aged five to 17 months in Burkina Faso --
where malaria accounts for around 22 percent of all deaths -- were given three
doses in 2019.
They were split into three groups, two receiving different doses of the
Matrix-M adjuvant, a vaccine ingredient patented by Novavax also used in the US
biotech firm's Covid jab. The third control group received a rabies vaccine.
Ahead of the 2020 rainy season -- when malaria cases surge -- 409 children
returned to get a booster shot.
For the group that received the higher dose of adjuvant, the booster rose
the protection level to 80 percent, according to the results of a phase 2b
trial published in The Lancet Infectious Diseases journal on Thursday. The
lower dose had 70 percent efficacy.
And crucially, the booster returned antibody levels to a similar level seen
after the first round of doses, the study said.
The study's lead investigator Halidou Tinto of the Burkina Faso health
research institute IRSS said, "It is fantastic to see such high efficacy
again after a single booster dose."
Tinto, who was involved in trialling both malaria vaccines, said GSK's vaccine
had an optimal efficacy of around 60 percent. "So I can confirm that R21
is doing much better," he told a press conference.
- 70% reduction in
deaths? -
Oxford vaccinologist and study co-author Adrian Hill said the vaccine meant
"We really could be looking at a very substantial reduction in that
horrendous burden of malaria, deaths and disease in the coming years, certainly
by 2030."
A 70 percent reduction in deaths from malaria could be feasible in that
time, he said, partly because of the vast number of vaccine doses that could be
quickly produced.
Oxford has partnered with the world's largest vaccine manufacturer, the
Serum Institute of India.
The institute is "willing and able to manufacture 200 million doses a
year starting next year," Hill said.
The six to 10 million doses that GSK can produce a year is "not enough
for 40 million children who need four doses in the first year," Hill
added.
And the Oxford vaccine would likely cost a few US dollars a dose, less than
half the $9 for GSK's version, he said.
The challenge of getting those doses into arms would require more funding,
he added.
Results from a phase three trial involving 4,800 participants across four
countries are expected later this year, which could potentially lead to
approval.
Azra Ghani, an epidemiologist at Imperial College London not involved in the
research, welcomed the results, saying it was "particularly
encouraging" the booster dose restored protective antibodies.
Gareth Jenkins of the charity Malaria No More UK said the results were
"another encouraging signal that, with the right support, the world could
end child deaths from malaria in our lifetimes".
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