South Africa COVID Strain May Weaken Impact of Vaccines, Says Top Scientist Shabir Madhi

There is growing concern that a new variant of COVID-19 first detected in South Africa may be more resistant to current vaccines than the original virus.

According to Shabir Madhi, a professor of vaccinology who is leading trials of the Oxford-AstraZeneca vaccine in South Africa, the mutated variant of the virus might "weaken the impact" of vaccines.

Madhi told BBC News that it was "unlikely" that the variant would render existing vaccines completely useless, but it may take several weeks of further research to find out.

The variant, which is known as 501Y.V2, is different to the strain of the virus that originated in the U.K. While both appear to be more transmissible than the original, there is no clear evidence to suggest that they cause any more serious an illness.

The 501Y.V2 variant was discovered in Nelson Mandela Bay, South Africa, in December, and it is known to have spread rapidly through the Eastern Cape, Western Cape, and KwaZulu-Natal provinces.

It has now also been detected in several countries around the world, including the U.K., Switzerland, Finland, Japan, Australia, Zambia, France and South Korea.

The 501Y.V2 variant has multiple mutations in the spike protein that enables the virus to infect human cells, and the fear is that these mutations could prevent antibodies from binding onto the virus.

John Bell, a professor who led the development of the AstraZeneca-University of Oxford COVID-19 vaccine, has also voiced concern about the effectiveness of current vaccines on the 501Y.V2 variant.

"The mutations associated with the South African form are really pretty substantial changes in the structure of the protein. The protein has a domain, which binds to the human cells—it's called the receptor-binding domain, and it's where the virus attaches itself," he said on Sunday.

"If you get an immune response that protects you, one of the ways it protects you is it gets in the way of that binding event. So you rely on antibodies to bind to that domain to stop the virus from binding onto yourself. That's basically the whole basis for vaccines. If you get an infection, you make antibodies to that domain that prevent you getting reinfected."

Like Madhi, Bell believes that current vaccines will still have an effect on the 501Y.V2 variant, if not the full effect.

However, he said it should be possible to make alterations to existing vaccines rendering them more effective against mutant strains of the virus, with the process taking up to six weeks.

A vial of Oxford-AstraZeneca COVID-19 vaccine
A close-up of an Oxford-AstraZeneca vaccine vial containing 10 doses at Pontcae Medical Practice on January 4, 2021 in Merthyr Tydfil, Wales. Top scientists have expressed concern that current vaccines could be less effective on mutant variants of COVID-19. Matthew Horwood/Getty Images