Covid antibodies last at least six months after infection
Coronavirus antibodies last for at least six months after infection for almost all people who have had the virus, according to a new study.
A wide-scale study, by medical database UK Biobank, found that 99 per cent of participants who tested positive for coronavirus retained antibodies for at least three months, while 88 per cent did so for at least six months.
The study lasted for six months. It is not currently known how long Covid antibodies last in total.
The research also suggested 8.8 per cent of the UK’s population had been infected by December.
London had the highest level of antibodies of any region in the country, with around 12 per cent of people across the capital previously having contracted the virus by December last year. As many as 14.7 per cent of people living in east London had antibodies at that time.
Professor Naomi Allen, chief scientist with UK Biobank, said: “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 between the end of May and December 2020, UK Biobank collected monthly blood samples and data on potential symptoms from 20,200 participants and their adult children and grandchildren.
There was no gender difference in antibody levels, 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).
The most common symptom associated with having antibodies was a loss of sense of taste and smell, which was reported by 43 per cent of people who had previously been infected with the virus.
Around a quarter of people with antibodies had contracted the virus completely asymptomatically, while 40 per cent did not have any of the three major tell-tale signs — a fever, persistent cough or loss of sense of taste or smell.
However, scientists warned that people with antibodies may still be able to pass the virus on to others.
Professor Sir Rory Collins, UK Biobank principal investigator said this meant it was “important to maintain the social distancing and the lockdown measures in line with the government guidance”.