Coronavirus: Thousands of NHS staff working while infected with virus, study suggests

A study of more than 1,000 hospital staff found 3 per cent were carrying the SARS-CoV-2 virus without feeling unwell, meaning they could have inadvertently helped spread the disease to patients.

If the results were replicated across the roughly 500,000 patient-facing staff in the NHS, it could mean as many as 15,000 workers may have been on duty while infected and able to pass the virus to others, including patients.

During April researchers at the University of Cambridge proactively swabbed 1,200 staff at Addenbrooke’s Hospital, part of Cambridge University Hospitals NHS Foundation Trust.

Of the 1,000 staff who reported feeling well and fit for work, 3 per cent tested positive for coronavirus.

With further questioning, one in five staff reported no symptoms, two in five had very mild symptoms that they had dismissed while a further two in five staff reported Covid-19 symptoms that had stopped more than a week earlier.

The study, published in the journal eLife, underlines the need to test both patients and staff, including those showing no symptoms, as the health service looks to re-start its normal operations.

The research also looked at where staff may have contracted the virus.

It found staff working in areas were there were Covid-19 patients were three times more likely to test positive for the virus than staff working in areas without infected patients. This is despite staff wearing protective equipment.

The research team said it was not clear whether the staff were infected at work or at home and those in higher risk areas were swabbed earlier in the study, closer to the start of lockdown when the virus was spreading more widely in the community.

Author Dr Mike Weekes, from the Cambridge Institute of Therapeutic Immunology and Infectious Disease, said hospitals should consider screening their workforce.

Dr Weekes said: “Test. Test. Test. And then test some more. All staff need to get tested regularly for Covid-19, regardless of whether they have any sort of symptoms – this will be vital to stop infection spreading within the hospital setting.”

Jonathan Ball, professor of molecular virology at the University of Nottingham, reacted to the study by saying: “This perfectly highlights how important aggressive testing can be in identifying, and therefore controlling, coronavirus spread. The study also highlights the benefits of routine testing of healthcare workers as these people are most at risk of becoming infected and can also be potential sources for hospital outbreaks.

“Controlling coronavirus spread in this setting will be important if the NHS and our hospitals are going to get back to offering important healthcare.”

Dr Joshua Moon, from the University of Sussex Business School, said: “Although the sample size is a little low to be banking on the 3 per cent number being precise, this study does highlight the importance of solving an open question of whether asymptomatic carriers can transmit the virus to others.

“On top of this, it highlights limitations in a strategy which focuses in on testing only those who are symptomatic, as it is likely to miss asymptomatic carriers which, if they can transmit the virus, would be a significant source of infection.”

The UK government suspended community testing in March as the coronavirus outbreak started to gather pace. Since increasing capacity ministers have re-started community testing and are looking to test all care home staff and residents, as well all patients admitted to hospital via A&E.