Study says COVID-19 infection provides immunity, but people can transmit virus

Previous COVID-19 infection provides some immunity for at least five months, but people may still carry and transmit the virus, according to a study by Public Health England.

A first report from PHE’s SIREN study found antibodies from previous COVID-19 infection provide 83% protection against reinfection for at least five months.

It found that reinfections in people with antibodies were rare, with only 44 potential reinfections among 6,614 participants who showed evidence of previous infection.

But a small number of people with antibodies may still be able to carry and transmit COVID-19 according to the study.

As a result, PHE stressed the importance of following “stay at home” rules currently in place in the UK to prevent the virus from spreading.

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.

SIREN study leaders are clear this first report provides no evidence towards the antibody or other immune responses from COVID-19 vaccines, nor should any conclusions be drawn on their effectiveness. The SIREN study will consider vaccine responses later this year.

Professor Susan Hopkins, senior medical advisor at Public Health England and the SIREN study lead said: “This study has given us the clearest picture to date of the nature of antibody protection against COVID-19 but 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.”

The news comes as the UK continues to endure high levels of infections despite a national lockdown.

There have been more than 74,000 deaths following coronavirus infections and nearly 43,000 new cases were recorded in the last day.

Last year the government announced that PHE is to be scrapped and merged with the NHS test and trace programme and the UK's Joint Biosecurity Centre.