Researchers have highlighted the importance of routinely screening healthcare staff for the SARS-CoV-2 virus after finding a high proportion of front-facing staff had the virus during the peak of the pandemic.
For the SAFER study, a UCLH team led by Dr Eleni Nastouli and Dr Catherine Houlihan are collecting twice-weekly self-administered nose and throat swabs and monthly blood samples from 200 staff in A&E, the Acute Medical Unit, the Infectious Diseases ward, the ICU and Haematology Services.
UCLH in partnership with the Crick tests swabs to assess whether staff were currently infected, and blood serum is tested for antibodies, which indicate previous exposure to the virus.
The overall aim of the study is to improve the evidence base around healthcare worker infection to inform our response to the pandemic to protect patients and staff.
Initial analysis of samples taken between 26 March and 8 April 2020 – the peak of the pandemic in London – revealed that 25% of healthcare staff tested had already had the infection, and a further 20% acquired infection within the first month of follow up. Overall, 45% of participants had evidence of having been infected with SARS CoV-2 at the peak of the pandemic and by the end of the first month of follow up.
Importantly, 38% of infections were not associated with symptoms within 7 days of the positive swab. For those who did develop symptoms, the average time to develop them was four days from a positive swab test. These results demonstrate the importance of regularly testing staff, including those who do not have symptoms, to prevent the spread of infection.
The study team informs any participant if they test positive for coronavirus via swab testing.
UCLH now carries out routine screening of staff and pre-admission testing of patients taking place at UCLH.
Dr Nastouli said: “Our results show why ongoing tracking of infection rates in staff is so important.
“We think there may be two main reasons for the high rates of infection we saw. First, we recruited staff at the peak of the pandemic in central London – and London is the city that has had the highest numbers of COVID-19 hospitalisations and deaths in the country.
“In addition, we specifically wanted to look at rates of infection in healthcare workers who are most at risk of infection and highly – which is why we recruited staff from intensive care, A&E and our COVID wards.
“The dedication of UCLH staff to complete the study under the challenging conditions of the pandemic response show how important the questions are and we would like to thank everyone that participated as well as the study funders.”
The research team will carry on with SAFER, plus a study that will last for a year where they will try to include all UCLH healthcare workers, estimate infectivity and rates of reinfection working with national programmes as well.