Oxford malaria vaccine: Promising results in trials

Published on Sep 09, 2022 09:29 PM IST

Scientists in Oxford, UK, say trials for a new malaria vaccine show it could have a "major impact." They hope to start producing doses by 2023.

Over 95% of the 200 million malaria cases each year are diagnosed in Africa, where fatality rates are highest in infants and babies(AFP)
Over 95% of the 200 million malaria cases each year are diagnosed in Africa, where fatality rates are highest in infants and babies(AFP)

So far, only one malaria vaccine has been designed for and distributed in Africa. Although it is significantly better than no vaccine at all, its efficacy rate is low — around 40%. The vaccine, produced by GSK, only started being widely distributed last year. (See pics: World Mosquito Day: Here's all you need to know about the 4 types of Malaria prevalent in India)

But a new vaccine, developed by Oxford scientists, may prove much more efficient at fighting malaria. Called R21, the jab proved 80% effective at guarding against the disease in a trial reported in the Lancet on September 7, 2022.

"Based on these results, this vaccine could have a major impact on the elimination of malaria from affected regions of the world," said Neil Mabbott, an immunopathology professor at the University of Edinburgh, who was not involved in the research. "This is a really remarkable achievement."

The scientists who led the trial say jabs could start being produced and distributed as early as next year. The vaccine is said to be cheap to make, and the Serum Institute of India, a vaccine maker, has pledged to produce 100 million doses per year.

Malaria kills about 600,000 people annually, most of whom are babies and children. Around 95% of the 200 million cases diagnosed per year are located on the African continent.

Creating a vaccine for malaria is difficult

It is not easy to make a vaccine for the disease, which is spread through mosquitoes, because the parasite that causes it evolves as it infects the body in order to avoid the immune system.

"The malaria parasite is constantly changing," said Mabbott. "This makes it difficult for our immune systems to detect and destroy it, and even more difficult to vaccinate against."

The R21 vaccine targets the first stage of the parasite's life cycle within the body, keeping it from spreading to and infecting the liver.

The R21 vaccine trial

In the trial, researchers found that a booster dose a year after the initial vaccination was on average 75% efficient at guarding against the virus.

Participants, all infants between the ages of 5 and 17 months, were recruited from a province in central Burkina Faso.

They were split into three groups: Two received the vaccine in different doses and a third, control group received a rabies vaccine. Overall, around 400 infants got the jab.

One group got a higher dose of the vaccine and were around 80% protected against the virus, while the other group got a lower dose and saw protection around 70%.

What's next for the R21 vaccine

The trial has been extended for two years to determine whether a four-dose vaccine regimen is enough, or if more booster doses will be necessary.

The initial data from this trial seemed to imply "that booster doses are likely to be needed to sustain protection," said Brian Greenwood, a professor of tropical medicine at the London School of Hygiene & Tropical Medicine, in a media briefing. Greenwood was not involved in the R21 research.

And the results of a much larger study — featuring 4,800 babies in four African countries — will also be published later in 2022. The large sample will be able to offer more specific insight into the vaccine's efficacy.

Edited by: Zulfikar Abbany

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