Efficacy of FFP3 respirators for prevention of SARS-CoV-2 infection in healthcare workers.

Mark Ferris,Rebecca Ferris,Geraldine Martell,Christine Moody,Emma Goldesgeyme,Nicholas J Matheson,David A Enoch,Christopher Jr Illingworth,Eoin O'Connor,Michael P Weekes,Chris Workman,Ashley Shaw,Natalie Quinnell,Jo Wright,Parth Patel

doi:10.7554/elife.71131

Abstract

Respiratory protective equipment recommended in the UK for healthcare workers (HCWs) caring for patients with COVID-19 comprises a fluid-resistant surgical mask (FRSM), except in the context of aerosol generating procedures (AGPs). We previously demonstrated frequent pauci- and asymptomatic severe acute respiratory syndrome coronavirus 2 infection HCWs during the first wave of the COVID-19 pandemic in the UK, using a comprehensive PCR-based HCW screening programme (Rivett et al., 2020; Jones et al., 2020). Here, we use observational data and mathematical modelling to analyse infection rates amongst HCWs working on 'red' (coronavirus disease 2019, COVID-19) and 'green' (non-COVID-19) wards during the second wave of the pandemic, before and after the substitution of filtering face piece 3 (FFP3) respirators for FRSMs. Whilst using FRSMs, HCWs working on red wards faced an approximately 31-fold (and at least fivefold) increased risk of direct, ward-based infection. Conversely, after changing to FFP3 respirators, this risk was significantly reduced (52-100% protection). FFP3 respirators may therefore provide more effective protection than FRSMs for HCWs caring for patients with COVID-19, whether or not AGPs are undertaken. Wellcome Trust, Medical Research Council, Addenbrooke's Charitable Trust, NIHR Cambridge Biomedical Research Centre, NHS Blood and Transfusion, UKRI.

Highlights

Consistent with World Health Organization (WHO) advice [1], UK Infection Protection Control guidance recommends that healthcare workers (HCWs) caring for patients with coronavirus disease 2019 (COVID-19) should use fluid resistant surgical masks type IIR (FRSMs) as respiratory protective equipment (RPE), unless aerosol generating procedures (AGPs) are being undertaken or are likely, when a filtering face piece 3 (FFP3) respirator should be used [2]
It has been suggested that respirators should be considered as a means of affording the best available protection [7], and some organisations have decided to provide FFP3 respirators to HCWs caring for COVID-19 patients, despite a lack of mandate from local or national guidelines [8]
The total number of cases of SARS-CoV-2 infection amongst HCWs at Cambridge University Hospitals NHS Foundation Trust (CUHNFT) increased throughout the study period, in keeping with the rising incidence of SARS-CoV-2 in the community (Figure 1 and Figure 1–source data 1)

Summary

Introduction

Consistent with World Health Organization (WHO) advice [1], UK Infection Protection Control guidance recommends that healthcare workers (HCWs) caring for patients with coronavirus disease 2019 (COVID-19) should use fluid resistant surgical masks type IIR (FRSMs) as respiratory protective equipment (RPE), unless aerosol generating procedures (AGPs) are being undertaken or are likely, when a filtering face piece 3 (FFP3) respirator should be used [2]. It has been suggested that respirators should be considered as a means of affording the best available protection [7], and some organisations have decided to provide FFP3 (or equivalent) respirators to HCWs caring for COVID-19 patients, despite a lack of mandate from local or national guidelines [8]. Respiratory protective equipment recommended in the UK for healthcare workers (HCWs) caring for patients with COVID-19 comprises a fluid resistant surgical mask (FRSM), except in the context of aerosol generating procedures (AGPs). We previously demonstrated frequent pauci- and asymptomatic SARS-CoV-2 infection HCWs during the first wave of the COVID-19 pandemic in the UK, using a comprehensive PCR-based HCW screening programme (Rivett et al, 2020; Jones et al, 2020)

Methods

Results

Conclusion