Wearing upgraded face masks can provide up to 100% protection against the coronavirus disease (Covid-19), a new study conducted by Cambridge University Hospitals (CUH) NHS Foundation Trust has found. The study showed a significant drop in infections among frontline hospital staff after their face masks were upgraded from FRSMs (fluid resistant surgical masks) to FFP3 respirators.
Since the early days of the Covid-19 pandemic, CUH has been screening its staff for the infection. The screening data was used to track infection rates among the staff. Even after using the recommended PPE kit, staff caring for Covid patients were at a much higher risk of infection compared to staff working in non-Covid wards, the CUH NHS Foundation Trust said in a statement.
Dr Mark Ferris, one of the co-authors of the study, said that the researchers developed a mathematical model to look at the risks faced by hospital staff caring for Covid-19 patients. According to their model, the risk of direct infection from working in a Covid ward before the change in respiratory protective equipment was 47 times higher than the risk of community-based exposure.
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In December 2020, the hospital upgraded its respiratory protective equipment to FFP3 respirators, which, once fitted, provide a tight seal around the nose and mouth, helping stop the airborne infection from being breathed in and out. According to the FFP3 respirators can be classified as FFP 1, FFP 2 or FFP 3, with the highest number providing the highest protection.
The study concluded that infections from ward-based exposure fell significantly, “with FFP3 respirators providing 31-100% protection (and most likely 100%)” against infection from Covid patients.
“Once FFP3 respirators were introduced, the number of cases attributed to exposure on Covid wards dropped dramatically – in fact, our model suggests that FFP3 respirators may have cut ward-based infection to zero,” Dr Chris Illingworth from the MRC Biostatistics Unit at the University of Cambridge, said.
The results are available in a pre-print and have not been peer-reviewed yet.
