Use of respirator vs. surgical masks in healthcare personnel and its impact on SARS-COV-2 acquisition-a prospective multicentre cohort study

ABSTRACT

Introduction: There is insufficient evidence regarding the role of respirators in the prevention of SARS-CoV-2 infection. Objectives: We analysed the impact of filtering facepiece class 2 (FFP2) vs. surgical masks on the risk of SARS-CoV-2 acquisition in Swiss healthcare workers (HCW). Methods: Our prospective multicentre cohort enrolled HCW from June to August 2020, who were asked about COVID-19 risk exposures/behaviours, including preferred mask type when caring for COVID-19 patients outside of aerosol-generating procedures (AGP). HCW performing AGP were also asked about universal FFP2 use (i.e. irrespective of patients' COVID-19 status). We assessed the impact of FFP2 on i) self-reported SARS-CoV- 2-positive nasopharyngeal PCR/rapid antigen tests (weekly surveys), and ii) SARS-CoV-2 seroconversion (baseline to January/February 2021). Results: We enrolled 3'259 participants from nine healthcare institutions, whereof 716 (22%) preferentially used FFP2 respirators. Among these, 81/716 (11%) reported a SARS-CoV-2-positive swab, compared to 352/2543 (14%) surgical mask users (median follow-up 242 days);seroconversion was documented in 85/656 (13%) FFP2 and 426/2255 (19%) surgical mask users. Adjusted for baseline characteristics, COVID-19 exposure, and risk behaviour, FFP2 use was marginally associated with a decreased risk for SARS-CoV-2-positive swab (aHR 0.8, p = 0.052) and seroconversion (aOR 0.7, p = 0.053);household exposure was the strongest risk factor (aHR for positive swab 10.1, p < 0.001;aOR for seroconversion 5.0, p < 0.001). In subgroup analysis, FFP2 use was clearly protective among HCW with frequent (> 20 patients) COVID-19 exposure (aHR 0.7, p < 0.001;aOR 0.6, p = 0.036). Universal FFP2 use during AGP showed no additional protective effect (aHR 1.1, p = 0.7;aOR 0.9, p = 0.53). Conclusion: FFP2 compared to surgical masks may convey additional protection from SARS-CoV-2 for HCW with frequent exposure to COVID-19 patients. (Figure Presented).