Unclear If COVID Vaccine Will Work on South African Strain: Top Scientist Sir John Bell

A top vaccine scientist has said it is still unclear whether current vaccines will be effective against a new variant of the novel coronavirus that was first detected in South Africa.

John Bell, a professor who led the development of the AstraZeneca-University of Oxford COVID-19 vaccine, told Times Radio that the South African variant—dubbed 501.V2—worried him more than another strain recently detected in the United Kingdom "by some margin."

Like the U.K. variant, the South African strain also appears to be more transmissible than the original. First detected in December, it has now been identified in a handful of other countries around the world, including France and Japan.

Both of the new variants, which share some similarities, have multiple genetic mutations, but the South African one features significant changes to the important "spike" protein that enables the SARS-CoV-2 virus to infect human cells.

These changes could potentially make vaccines less effective against this variant, according to Bell, although more research needs to be conducted in order to properly understand this issue.

"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," Bell told Times Radio 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. So, if you mess around with that, you're in trouble."

Bell said that scientists were now looking at the "crucial question" of whether or not vaccines will be effective against the new variants detected in the U.K. and South Africa—neither of which appear to cause more serious disease.

"I can't give you an insight now," Bell said. "My gut feeling is that I think the vaccine will be still effective against the [U.K.] strain. And I don't know about the South African strain. I think that's a there's a big question mark about that."

Bell said there is still some headroom with the vaccines that are currently available, because they work "much better" than anyone would have predicted previously.

"We do have some room to manoeuvre if they worked 20 percent less well because of mutation. We'd still have good vaccines in my view. I think it's unlikely that these mutations will turn off the effect of vaccines entirely, I think you'll still have a residual effect," Bell said.

If necessary, Bell said that it was "perfectly possible" to tweak existing vaccines so that they are effective against the new strain and that this would not take a whole year.

"It might take a month or six weeks to get a new vaccine. So everybody should stay calm, it's going to be fine. But we're now in a game of cat and mouse, because these are not the only two variants we're going to see. We're going to see lots of variants."

Simon Clarke, an associate professor in cellular microbiology at the University of Reading, in the U.K., said in a statement that the South African variant has more extensive alteration to the spike protein than the U.K. variant.

He said this may "make the virus less susceptible to the immune response triggered by the vaccines."

But Francois Balloux, a professor of computational systems biology at University College London, was more cautious about this possibility.

"It is not anticipated that this mutation is sufficient for the 'South African' variant to bypass the protection provided by current vaccines," he said in a statement. "It's possible that new variants will affect the efficacy of the COVID vaccines, but we shouldn't make that assumption yet about the South African one."

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A nurse administers a dose of the AstraZeneca-Oxford COVID-19 vaccine to a patient at the Pontcae Medical Practice in Merthyr Tydfil in south Wales on January 4, 2021. GEOFF CADDICK/AFP via Getty Images