Fears South African strain of virus may reduce the effectiveness of vaccine


he South African variant of Covid may reduce the effectiveness of existing vaccines because of its ability to evade detection, experts fear.

Health Secretary Matt Hancock said yesterday that he was “incredibly worried” about the threat posed by the variant, which has added to problems already created by another variant that was discovered in Kent and which has increased UK cases by up to 70 per cent.

Research is under way at Porton Down laboratory to determine whether the variants could render the Pfizer or Oxford vaccines less effective, with preliminary results expected next week.

Professor Francois Balloux, director of the UCL genetics institute, said the South African variant had a mutation in its Covid spike protein that had been shown to reduce antibody recognition. This helps it bypass immune protection provided by antibodies from prior infection or vaccination, he said.

He told the Standard: “One issue with the South African variant is that it carries one mutation which we know plays a role in immune regulation — it’s a site where neutralising antibodies bind.  

“As such, it might slightly reduce vaccine efficacy. We don’t really know yet, but it’s not impossible.”

He said there was “very good evidence” that the Kent variant didn’t cause more severe disease despite being more infectious — and even the possibility that it might lead to less severe symptoms.

The South African variant was first detected in October and some cases have been traced in the UK. The UK imposed a flight ban on South Africa prior to Christmas.

Oxford University’s Professor Sir John Bell said his “gut feeling” was that the current vaccines would be effective against the Kent strain but there was a “big question mark” over their ability to fight the South African variant.  

Prof Balloux said it would be “relatively straightforward” to reprogramme vaccines to combat emerging strains and said closely following the lockdown rules would protect against the virus.

Professor Lawrence Young, of Warwick university, said: “While changes in the UK variant are unlikely to impact the effectiveness of current vaccines, the accumulation of more spike mutations in the South African variant are more of a concern and could lead to some escape from immune protection.”


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