People can still carry and transmit Covid-19 after recovering from the virus, according to early evidence from Public Health England’s SIREN study.
The same study found people infected with Covid-19 in the past are likely to be protected against reinfection for at least five months.
But experts cautioned those with immunity may still be able carry the virus in their nose and throat and therefore have a risk of transmitting it to others.
They urged people who’ve had Covid-19 already to continue following social distancing guidelines, particularly paying attention to ‘Hands, Face, Space’.
Public Health England has been regularly testing tens of thousands of health care workers across the UK since June for new Covid-19 infections, as well as the presence of antibodies, which suggest people have been infected before.
Between 18 June and 24 November 2020, scientists detected 44 potential reinfections out of 6,614 participants who had tested positive for antibodies. This represents an 83% rate of protection from reinfection.
This appears to last at least for five months from first becoming sick.
While the SIREN study will continue to assess whether protection may last for longer, this means people who contracted the disease in the first wave of the pandemic back in March 2020 may now be vulnerable to catching it again.
PHE said it’s crucial everyone continues to follow the rules and stays at home, even if they’ve previously had Covid-19, to prevent spreading the virus.
Professor Susan Hopkins, senior medical advisor at PHE and the SIREN study lead, said the study has given us “the clearest picture to date” of the nature of antibody protection against Covid-19.
But she said it is “critical” people do not misunderstand these early findings.
“We now know that most of those who have had the virus, and developed antibodies, are protected from reinfection, but this is not total and we do not yet know how long protection lasts. Crucially, we believe people may still be able to pass the virus on,” she added.
“This means even if you believe you already had the disease and are protected, you can be reassured it is highly unlikely you will develop severe infections but there is still a risk that you could acquire an infection and transmit to others.
“Now more than ever it is vital we all stay at home to protect our health service and save lives”
SIREN study leaders said this first report provides no evidence towards the antibody or other immune responses from Covid-19 vaccines. The study will consider vaccine responses later this year.
This article originally appeared on HuffPost UK and has been updated.