Microbial contamination of powered air purifying respirators (PAPR) used by healthcare staff during the COVID-19 pandemic: an in situ microbiological study.

Background: Powered air purifying respirators (PAPR) are an option for healthcare workers requiring respiratory protection during the current COVID-19 pandemic; they are shared between multiple people. PAPR hoods are intended for multiple uses by a single user and may pose an infection risk between wearers.

Methods: Internal components of PAPR hoods and corrugated air supply hoses were swabbed for evidence of bacterial, fungal, common respiratory viruses and severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) contamination.

Results: Twenty-five PAPR hoods were swabbed; 10 (40%) returned positive results. Bacterial growth was detected on six PAPR; five of the PAPR tested positive for fungal growth; all tested negative for SARS-CoV-2 and common respiratory viruses.

Conclusions: Bacteria and fungi can remain on internal components of PAPR hoods and air supply hoses despite following recommended disinfection procedures. PAPR hoods have the potential to act as fomites, cross-infecting wearers, and patients. Current guidelines for disinfecting PAPR hoods may not be effective for use in high risk healthcare environments.