Previous Covid-19 infection provides some immunity for at least five months, but people may still carry and transmit the virus, according to a new study.
Experts have warned that a small number of those with immunity may still be able to carry the virus in their nose and throat and therefore have a risk of transmitting it to others.
The first report from Public Health England's (PHE) Siren study found that antibodies from past infection provide 83% protection against reinfection for at least five months.