COVID-19 infection confers some immunity for at least five months, UK study finds

LONDON (Reuters) – People who have had COVID-19 are very likely to be immune to this virus for at least five months, but there is evidence that those with antibodies may still be able to carry and spread the virus. virus, a British study of healthcare workers has found.

FILE PHOTO: A healthcare worker takes a swab sample from a woman to be tested for coronavirus disease (COVID-19), at a bus terminal in Buenos Aires, Argentina, January 12, 2021. REUTERS / Agustin Marcarian

Preliminary results from scientists at Public Health England (PHE) have shown that re-infections in people who have COVID-19 antibodies from a previous infection are rare – with just 44 cases found among 6,614 people previously infected in the study.

But experts have warned that the results mean people who contracted the disease in the first wave of the pandemic in the early months of 2020 may now be vulnerable to contracting it again.

They also warned that so-called “natural immune” people – acquired after having the infection – may still be able to carry the SARS-CoV-2 coronavirus in their nose and throat, and could pass it on without it. want to.

“We now know that most of those who have had the virus and have developed antibodies are protected against reinfection, but it is not total and we do not yet know how long the protection lasts,” said Susan. Hopkins, senior medical advisor at PHE and co-leader of the study, the results of which were released Thursday.

“This means that even if you think you have had the disease before and are protected, you can be reassured that you are very unlikely to develop serious infections. But there is always a risk of getting an infection and passing it on to others. “

A statement on the study said its findings did not address antibodies or other immune responses to vaccines currently being deployed against COVID-19, nor the effectiveness of the vaccines. Vaccine responses will be reviewed later this year, he said.

The research, known as the SIREN study, involves tens of thousands of healthcare workers in Britain who have been tested regularly since June for new COVID-19 infections as well as for the presence of antibodies.

Between June 18 and November 24, scientists detected 44 potential re-infections – two “probable” and 42 “possible” – out of 6,614 participants who had tested positive for antibodies. This represents an 83% protection rate against reinfection, they said.

Researchers plan to continue to monitor and assess participants to see if this natural immunity might last longer than five months in some. But they warned that early evidence from the next stage of the study already suggests that some immune people may still carry high levels of the virus and could pass it on to others.

“So it is crucial that everyone continues to follow the rules and stay at home, even if they have already had COVID-19,” they said in the statement about their results.

Reporting by Kate Kelland; Edited by Mark Heinrich

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