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Covid vaccines may work better than thought against variants, say researchers

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Vaccines may be more effective against Covid variants than previously thought, research suggests.

Researchers from the University of Oxford found that antibodies from natural infection and existing vaccines are able to neutralise Brazilian and South African variants albeit at lower levels than the strain circulating at the start of the pandemic.

Their work, so far published as a pre-print, suggests that the ability of the P1 ‘Brazilian’ strain to resist immunity from current vaccines may not be as bad as had been feared.

Study leader Professor Gavin Screaton said the results extend researchers understanding of the role of changes in the spike protein in evading the immune response for the South African, Brazilian and Kent variants.

The team looked at neutralisation of the strains using blood samples from people with natural antibodies after Covid-19 infection and from those with antibodies as a result of vaccination with Oxford-AstraZeneca and Pfizer-BioNTech vaccines.

They found a nearly three-fold reduction in the level of virus neutralisation by the antibodies generated by the vaccines for the Kent and Brazilian variants compared with the original strain, and a 9-fold (AstraZeneca) and 7.6-fold (Pfizer) reduction against the South African strain.  

Other research has shown lower protection of the Oxford-Astra Zeneca vaccine with the South African variant and the team concluded that focus of vaccine developers should be on the South African strain as they consider potential modifications.

They believe that the drop in vaccine efficacy against mild to moderate disease with the South African variant probably reflects mutations occurring outside the receptor binding domain.  

Professor Andrew Pollard, chief investigator on the Oxford University vaccine trial, said: ‘These further efforts to investigate the relationship between changes in the virus and human immunity provide new insights that help us be prepared to respond to further challenges to our health from the pandemic virus, if we need to do so.’

Almost half of UK adults have now had a Covid-19 vaccine, figures show. It comes alongside news of tighter vaccine supply over the next month but reassurances from the health secretary that people would have their second doses.

Latest data from the Office for National Statistics shows that 94% of people say they have had or would be willing to have a Covid-19 vaccine. The figures do differ with age with 87% of those aged 16 to 29 years saying they are likely to take up the offer.

The most recent ONS figures also show that infections, hospital admissions and deaths involving Covid-19 continued to decrease in England and a third of people now have antibodies against the virus.  

But the latest data on infections does show a bit of a mixed picture, the ONS said with a slowing in the rate of decline for some and and uncertain trend in other areas and early signs of an increase in the East Midlands.  

In Scotland, the percentage of people testing positive appears to have increased in the most recent weekly data.