Upgrading the quality of face masks worn by NHS healthcare workers made a dramatic difference to their risk of being infected by the SARS-CoV-2 virus, a preprint study has suggested.
Until recently, advice from Public Health England stated that healthcare workers caring for patients with COVID-19 should use fluid resistant surgical masks type IIR (FRSMs) for routine work caring for COVID-19 patients.
However, researchers at the University of Cambridge and Cambridge University Hospitals Trust found that those staff who switched to higher grade filtering face piece (FFP3) masks received up to 100% protection from hospital-acquired SARS-CoV-2 infections.
Addenbrooke’s Hospital Trial
The data was gathered during a programme of regular testing for COVID at Addenbrooke’s hospital, during which its infection control committee implemented a change in respiratory protective equipment from FRSMs to FFP3 respirators for healthcare professionals involved in high-risk care, such as aerosol-generating procedures.
Dr Mark Ferris from the University of Cambridge’s Occupational Health Service, and one of the study’s authors, said: “Healthcare workers – particularly those working on COVID-19 wards – are much more likely to be exposed to coronavirus, so it’s important we understand the best ways of keeping them safe.
“Based on data collected during the second wave of the SARS-CoV-2 pandemic in the UK, we developed a mathematical model to look at the risks faced by those staff dealing with COVID-19 patients on a day-to-day basis. This showed us the huge effect that using better PPE could have in reducing the risk to healthcare workers.”
Modelling suggested that the risk of direct infection from working on a COVID-19 ward before the change in respiratory protective equipment was 47 times greater than for staff working on a non-COVID-19 ward.
Dr Chris Illingworth from the MRC Biostatistics Unit at the University of Cambridge, commented: “Before the face masks were upgraded, the majority of infections among healthcare workers on the COVID-19 wards were likely due to direct exposure to patients with COVID-19.
“Once FFP3 respirators were introduced, the number of cases attributed to exposure on COVID-19 wards dropped dramatically – in fact, our model suggests that FFP3 respirators may have cut ward-based infection to zero.”
Dr Nicholas Matheson from the Department of Medicine at the University of Cambridge, said: “Although more research will be needed to confirm our findings, we recommend that, in accordance with the precautionary principle, guidelines for respiratory protective equipment are further revised until more definitive information is available.”
Dr Michael Weekes, also from the Department of Medicine at Cambridge, said upgrading the standard of masks for healthcare workers caring for COVID “could reduce the number of infections, keep more hospital staff safe and remove some of the burden on already stretched healthcare services caused by absence of key staff due to illness”.
‘Vital’ to Protect Staff
Health bodies have repeatedly campaigned for improvements in PPE for staff. Rose Gallagher, professional lead for infection prevention and control at the Royal College of Nursing (RCN), said: “This important study adds even further weight to the RCN’s continuing call for nursing staff to be better protected from COVID-19 and given routine access to the highest levels of respiratory protective equipment whenever they need it.
“We are still seeing cases of COVID-19, even from some who have been vaccinated, and it is vital staff are fully protected and there are no attempts to restrict or ease off on measures to further reduce the risk of infection.”
The researchers said although the findings had yet to be peer-reviewed, they were releasing the results early because of an urgent need to share information relating to the pandemic.
