Hundreds of staff at Hull’s hospitals have played a crucial role in a scientific study which has discovered people are protected from catching Covid-19 again for at least five months after contracting the virus.

Staff at Hull University Teaching Hospitals NHS Trust took part in the SIREN study, undertaken by Public Health England (PHE) to see if health care workers who had already contracted the virus had any immunity to future infection.

In its first report produced today, PHE has revealed:

• antibodies from past Covid-19 infection provide people who have already had the virus with 83 per cent protection against reinfection for at least five months;
• Reinfections were rare with just 44 potential reinfections in the study of 6,614 people who had antibodies after contracting the virus earlier

However, early evidence does suggest a small number with antibodies may still be able to carry and transmit Covid-19, underlining the need for people to follow national guidance to stay at home and the rules of “hands, face, space” whether they have had the infection or not.

Phillipa Burns, Higher Specialist Scientific Trainee Clinical Scientist, led the SIREN study involving 550 staff at Hull Royal Infirmary and Castle Hill Hospital.

She said: “The findings are really encouraging and it’s fantastic that staff working on the frontline during the pandemic have contributed so much to our understanding of this terrible disease and how it works.

“By taking part in this major study, our staff are playing a huge role in determining our future response to the virus.”

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.

However, the first report provides no evidence towards the antibody or other immune responses from Covid-19 vaccines and those involved no conclusion should be drawn on their effectiveness. The SIREN study will consider vaccine responses later this year.

PHE scientists working on the study have concluded naturally acquired immunity as a result of past infections provide 83 per cent protection against reinfection, compared to people who have not had the disease before. 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 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.”