When Addenbrooke’s Hospital in Cambridge upgraded its face masks for staff working on COVID-19 wards to filtering face piece 3 (FFP3) respirators, it saw a dramatic fall – up to 100% – in hospital-acquired SARS-CoV-2 infections among these staff. The findings are reported by a team at the University of Cambridge and Cambridge University Hospitals (CUH) NHS Foundation Trust. The research has not yet been peer-reviewed, but is being released early because of the urgent need to share information relating to the pandemic.
"By contrast, the risk of direct infection from working on a COVID-19 ward before the change in respiratory protective equipment was considerably higher than the risk of community-based exposure: staff on COVID-19 wards were at 47 times greater risk of acquiring infection while on the ward than staff working on a non-COVID-19 ward.
Crucially, however, the model showed that the introduction of FFP3 respirators provided up to 100% protection against direct, ward-based COVID-19 infection."
https://www.cam.ac.uk/research/news...cut-hospital-acquired-infections-dramatically