Coronavirus antibodies last for at least six months after infection for the majority of people who have had the virus, according to a study.
A study from UK Biobank, the UK’s major biomedical database and research resource, measured the levels of previous infection in various population groups across the UK. It also looked at how long antibodies persisted in those who were infected.
According to the study, 99 per cent of participants who had tested positive for previous infection retained coronavirus antibodies for three months after being infected, while 88 per cent did so for the full six months of the study.
Researchers say this indicates antibodies produced following natural infection may provide a degree of protection for most people against getting infected again for at least six months.
The research found that 8.8 per cent of the UK population had been infected by December 2020, rising as high as 12.4 per cent in London and as low as 5.5 per cent in Scotland.
The UK Biobank chief scientist, Professor Naomi Allen, said: “This important study has revealed that the vast majority of people retain detectable antibodies for at least six months after infection with the coronavirus.
“Although we cannot be certain how this relates to immunity, the results suggest that people may be protected against subsequent infection for at least six months following natural infection.
“More prolonged follow-up will allow us to determine how long such protection is likely to last.”
For the six-month period from the end of May 2020 to the beginning of December 2020, UK Biobank collected monthly blood samples and data on potential symptoms from 20,200 UK Biobank participants and their adult children and grandchildren.
The study also found that the proportion of the population with antibodies to SarsCoV-2 (seroprevalence, which indicates past infection) rose from 6.6 per cent at the start of the study period, to 8.8 per cent by the end of it.
There was no difference in seroprevalence by gender, but the proportion of participants with detectable antibodies was highest in younger people (13.5 per cent among those under 30) and lowest in the elderly (6.7 per cent among those over 70), according to the study.
The seroprevalence of Sars-CoV-2 was highest among participants of black ethnicity (16.3 per cent) and lowest among those of white (8.5 per cent) and Chinese ethnicities (7.5 per cent).
The most common symptom associated with having coronavirus antibodies was a loss of sense of taste and smell, which was reported by 43 per cent of sero-positive participants.
Around one quarter (24 per cent) of sero-positive participants were completely asymptomatic, and 40 per cent did not have one of the three classic Covid-19 symptoms – fever, persistent dry cough or loss of sense of taste or smell.