About 88% of people still have antibodies in their blood to fight Covid-19 six months after infection.

This is the conclusion of a UK study of almost 1,700 people, BBC reports.

UK Biobank chief scientist Prof Naomi Allen said:

Although we cannot be certain how the presence of antibodies] 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."

The UK Biobank is a database of blood, urine and saliva samples, heart and brain scans and the genetic data of half a million people who volunteered to have their information analysed to help with global medical research.

Re-infection possible

The new coronavirus, Sars-CoV-2, has not been around long enough to know how long immunity lasts.

Some people are reinfected, however, and, even if asymptomatic, can then harbour high levels of the virus in their noses and mouths, which can be passed on to others, scientists warn.