LONDON (Reuters) – Almost everyone previously infected with COVID-19 has high levels of antibodies for at least six months that are likely to protect them from re-infection with the disease, results of a large British study.
Scientists said the study, which measured levels of previous COVID-19 infection in populations across Britain, as well as how long antibodies persist in those infected, should provide some assurance that rapid cases of reinfection will be rare.
“The vast majority of people retain detectable antibodies for at least six months after infection with the coronavirus,” said Naomi Allen, professor and chief scientist at UK Biobank, where the study was conducted.
Of the participants who had tested positive for a previous COVID-19 infection, 99% retained antibodies against SARS-CoV-2 for three months, the results showed. After the full six months of study follow-up, 88% still had them.
“While we can’t be sure how this relates to immunity, the results suggest that people can be protected from further infection for at least six months after natural infection,” Allen said.
She said the results were also consistent with the results of other studies in the UK and Iceland which found that antibodies to the coronavirus tended to persist for several months in those who have had the disease and become ill. are restored.
A study of British healthcare workers released last month found people who had COVID-19 were likely to be protected for at least five months, but noted that those who had antibodies may still be able carry and spread the virus.
The UK Biobank study also found that the proportion of the UK population with COVID-19 antibodies – a measure known as seroprevalence – increased from 6.6% at the start of the study period in May / June 2020 at 8.8% in November / December 2020.
The seroprevalence of SARS-CoV-2 was most common in London, at 12.4%, and least common in Scotland at 5.5%, according to the report.
Reporting by Kate Kelland; Edited by Alison Williams