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