Major Article
Assessment of half-mask elastomeric respirator and powered air-purifying respirator reprocessing for an influenza pandemic

https://doi.org/10.1016/j.ajic.2017.06.034Get rights and content

Highlights

  • Manual reprocessing for reusable respirators were evaluated against influenza and soiling agent.

  • Across 41 surfaces tested, the mean log reduction in viable virus was > 4.5 log TCID50.

  • Cleaning alone demonstrated similar efficacy as cleaning and disinfection procedures.

  • Respirator design and materials may impact reprocessing effectiveness.

Background

Health care facilities are considering the use of reusable respiratory protective devices (RPDs) to mitigate a potential N95 filtering facepiece respirator shortage caused by an influenza pandemic. US regulators are also considering stockpiling reusable RPDs for pandemic preparedness, but limited data exist on the effectiveness of cleaning and disinfection of these devices. This study defines reprocessing protocols and evaluates their effectiveness against a pandemic influenza strain in a laboratory setting.

Methods

Five half-mask elastomeric respirator models and 3 powered air-purifying respirator models were contaminated with influenza virus and artificial skin oil on multiple surfaces. RPDs were then manually treated with 1 of 2 methods: cleaned or cleaned and disinfected. Presence of viable influenza was determined via swab sampling and a median tissue culture infectious dose assay.

Results

Across 41 RPD surfaces, a mean log reduction in viable influenza of 4.54 ± 0.97 log10 median tissue culture infectious dose was achieved for all treated surfaces, which included both cleaned and cleaned and disinfected surfaces.

Conclusions

The methods defined as part of this study are effective for eliminating viable influenza in the presence of artificial skin oil on most of the RPD surfaces tested. Material type and RPD design should be considered when implementing RPD reprocessing protocols.

Section snippets

H1N1 influenza

H1N1 influenza A/PR/8/34 (ATCC VR-1469) was propagated in embryonic chicken eggs (Charles River Premium Specific Pathogen Free Eggs 10100326) using standard World Health Organization (WHO) protocols.28 Virus titers were determined by 50% tissue culture infectious dose (TCID50) assay. Madin-Darby canine kidney cells (ATCC CCL-34) were passaged and maintained using WHO-approved cell culture techniques.

Test respirators

Five commercially available HMER models and 3 commercially available PAPR models were tested for

HMER reprocessing studies

The mean viable influenza recovered from all untreated HMER surfaces was 4.76 ± 1.23 log10 TCID50 (Fig 1). A mean recovery of 5.15 ± 0.79 log10 TCID50 was achieved for nonporous surfaces and 3.24 ± 1.23 log10 TCID50 was recovered from porous surfaces (fabric straps). For cleaned-only surfaces, the mean log reduction was 4.55 ± 0.79, and only 2 of 24 surfaces demonstrated recoverable viable virus: 0.97 ± 1.33 log10 TCID50 from the fabric strap of the Scott model (Scott Safety, Monroe, NC) and

Discussion

This study demonstrates the decontamination effectiveness of the RPD reprocessing protocols defined as part of this study against H1N1 influenza in the presence of a heavy soiling agent. Twenty-four different HMER surfaces and 17 different PAPR surfaces were evaluated to account for differences in material properties and surface types. All treated surfaces demonstrated a mean log reduction of 4.54 ± 0.97 log10 TCID50, indicating this reprocessing approach may significantly reduce fomite

Conclusions

The effectiveness demonstrated by the reprocessing protocols evaluated as part of this study indicates that HMERs and PAPRs can be effectively disinfected when challenged with a pandemic influenza strain in the presence of soiling agents. Of 41 surfaces tested, only 1 demonstrated recoverable viable virus after being both cleaned and disinfected, indicating that the likelihood of these devices acting as fomites after proper use of the reprocessing protocols evaluated here is low. The data from

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    Supported by the US Food and Drug Administration Medical Countermeasures Initiative Regulatory Science Extramural Research Program (contract No. HHSF223201400158C).

    The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health or the Food and Drug Administration.

    Conflicts of interest: None to report.

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