SIREN study finds past COVID-19 infection provides some immunity for at least five months

A woman takes a blood sample from a participant


The first report from Public Health England’s SIREN study finds antibodies from past COVID-19 infection provide 83% protection against reinfection for at least 5 months - however some people with antibodies may still carry and transmit the virus.

Low levels of reinfection

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. Supported by the King's CRF, almost 500 staff members from across King's College Hospital Trust are currently enrolled in the study.

In the study, experts found just 44 cases of potential reinfection among 6,614 participants who had antibodies to COVID-19 (indicating previous infection). This equates to 83% protection against reinfection, compared to people who have not had the disease before, and the protection appears to last at least for five months from first becoming sick.

However, early evidence also suggests a small number of people with antibodies may still be able to carry and transmit COVID-19. Public Health England continues to stress the importance of following the stay at home rules and remembering hands, face, space - whether you have had the virus or not.

Cautious optimism

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 to be drawn on their effectiveness. The SIREN study will consider vaccine responses later this year. 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 may now be vulnerable to catching it again.

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.

“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.

“We are immensely grateful to our colleagues in the NHS for giving up their time to volunteer, and whose continued participation at a time of great stress is making this research possible.”

Read the full press release here.

Tags: NIHR Wellcome King's Clinical Research Facility - Covid-19 -

By NIHR Wellcome King's Clinical Research Facility at 19 Jan 2021, 13:18 PM

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