Researchers from the Institut Pasteur, France, have carried out a study that tested the sensitivity of United Kingdom and South African variants of the coronavirus.

For the study, the researchers examined the serum samples of people who have been vaccinated or previously contracted Covid-19.

They compared this sensitivity with that of the reference virus (D614G), which was until recently the most widespread strain in France.

The findings of the study indicated that the UK variant is neutralized to the same degree as D614G. However, the South African variant is less sensitive to neutralising antibodies.

The researchers stressed that to neutralise the South African variant, the antibody concentrations need to be six times higher than for D614G.

This difference in sensitivity was also observed in vaccinated individuals. The authors of the study found that the antibodies in their serum are effective against the UK variant but less so against the South African one.

The results of the study showed that the UK variant (B.1.1.7) was neutralised by 95 per cent (79 out of 83) of the serum of people who had been infected with SARS-CoV-2 and whose samples were taken up to nine months after the onset of symptoms. The same proportions were observed for the D614G strain.

However, the scientists noticed a decline in neutralising activity against the South African variant in 40 per cent of the serum samples of individuals who had been exposed to the virus, for samples taken nine months after the primary infection.

The findings of the study were published in the journal Nature Medicine.

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