1. Epidemiology and Global Health
  2. Microbiology and Infectious Disease
Download icon

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

  1. Mark Ferris  Is a corresponding author
  2. Rebecca Ferris
  3. Chris Workman
  4. Eoin O'Connor
  5. David A Enoch
  6. Emma Goldesgeyme
  7. Natalie Quinnell
  8. Parth Patel
  9. Jo Wright
  10. Geraldine Martell
  11. Christine Moody
  12. Ashley Shaw
  13. Christopher J R Illingworth
  14. Nicholas J Matheson
  15. Michael P Weekes  Is a corresponding author
  1. University of Cambridge Occupational Health and Safety Service, United Kingdom
  2. Cambridge University Hospitals NHS Trust, United Kingdom
  3. School of Clinical Medicine, University of Cambridge, United Kingdom
  4. Cambridge Biomedical Campus, United Kingdom
  5. University of Cambridge, United Kingdom
  6. Cambridge Institute for Medical Research, University of Cambridge, United Kingdom
Research Advance
  • Cited 0
  • Views 480
  • Annotations
Cite this article as: eLife 2021;10:e71131 doi: 10.7554/eLife.71131

Abstract

Background: 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: Here, we use observational data and mathematical modelling to analyse infection rates amongst HCWs working on 'red' (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.

Results: Whilst using FRSMs, HCWs working on red wards faced an approximately 31-fold (and at least 5-fold) increased risk of direct, ward-based infection. Conversely, after changing to FFP3 respirators, this risk was significantly reduced (52-100% protection).

Conclusions: FFP3 respirators may therefore provide more effective protection than FRSMs for healthcare workers caring for patients with COVID-19, whether or not AGPs are undertaken.

Funding: Wellcome Trust, Medical Research Council, Addenbrooke's Charitable Trust, NIHR Cambridge Biomedical Research Centre, NHS Blood and Transfusion, UKRI.

Data availability

All data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided for Figures 1 and 3, and their supplements. Figure 2 source data is included in a table in the main text.

Article and author information

Author details

  1. Mark Ferris

    University of Cambridge Occupational Health and Safety Service, Cambridge, United Kingdom
    For correspondence
    mark.ferris@addenbrookes.nhs.uk
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-5040-4263
  2. Rebecca Ferris

    Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  3. Chris Workman

    Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  4. Eoin O'Connor

    School of Clinical Medicine,, School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-6846-6881
  5. David A Enoch

    Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  6. Emma Goldesgeyme

    Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  7. Natalie Quinnell

    Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  8. Parth Patel

    Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  9. Jo Wright

    Occupational Health and Wellbeing, Cambridge Biomedical Campus, Cambridge, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  10. Geraldine Martell

    Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  11. Christine Moody

    Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  12. Ashley Shaw

    Cambridge University Hospitals NHS Trust, Cambridge, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  13. Christopher J R Illingworth

    MRC Biostatistics Unit, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-0030-2784
  14. Nicholas J Matheson

    Department of Medicine, University of Cambridge, Cambridge, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-3318-1851
  15. Michael P Weekes

    Department of Medicine, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
    For correspondence
    mpw1001@cam.ac.uk
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-3196-5545

Funding

Wellcome Trust (108070/Z/15/Z)

  • Michael P Weekes

Addenbrooke's Charitable Trust, Cambridge University Hospitals

  • Michael P Weekes

NIHR Cambridge Biomedical Research Centre

  • Michael P Weekes

Medical Research Council (MR/P008801/1)

  • Nicholas J Matheson

NHS Blood and Transfusion (WPA15-02)

  • Nicholas J Matheson

UK Research and Innovation (MR/V038613/1)

  • Christopher J R Illingworth

Medical Research Council (MC_UU_00002/11)

  • Christopher J R Illingworth

Medical Research Council (MC_UU_12014)

  • Christopher J R Illingworth

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Ethics

Human subjects: This study was conducted as a service evaluation of the CUHNFT staff testing services and PPE policy (CUHNFT clinical project ID3738). As a study of healthcare-associated infections, this investigation is exempt from requiring ethical approval under Section 251 of the NHS Act 2006 (see also the NHS Health Research Authority algorithm, available at http://www.hra-decision-tools.org.uk/research/, which concludes that no formal ethical approval is required).

Reviewing Editor

  1. Jos W Van der Meer, Radboud University Medical Centre, Netherlands

Publication history

  1. Received: June 18, 2021
  2. Accepted: November 7, 2021
  3. Accepted Manuscript published: November 16, 2021 (version 1)

Copyright

© 2021, Ferris et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

Metrics

  • 480
    Page views
  • 58
    Downloads
  • 0
    Citations

Article citation count generated by polling the highest count across the following sources: Crossref, PubMed Central, Scopus.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Download citations (links to download the citations from this article in formats compatible with various reference manager tools)

Open citations (links to open the citations from this article in various online reference manager services)

  1. Further reading

Further reading

    1. Epidemiology and Global Health
    Andria Mousa et al.
    Research Article

    Background: Transmission of respiratory pathogens such as SARS-CoV-2 depends on patterns of contact and mixing across populations. Understanding this is crucial to predict pathogen spread and the effectiveness of control efforts. Most analyses of contact patterns to date have focussed on high-income settings.

    Methods: Here, we conduct a systematic review and individual-participant meta-analysis of surveys carried out in low- and middle-income countries and compare patterns of contact in these settings to surveys previously carried out in high-income countries. Using individual-level data from 28,503 participants and 413,069 contacts across 27 surveys we explored how contact characteristics (number, location, duration and whether physical) vary across income settings.

    Results: Contact rates declined with age in high- and upper-middle-income settings, but not in low-income settings, where adults aged 65+ made similar numbers of contacts as younger individuals and mixed with all age-groups. Across all settings, increasing household size was a key determinant of contact frequency and characteristics, with low-income settings characterised by the largest, most intergenerational households. A higher proportion of contacts were made at home in low-income settings, and work/school contacts were more frequent in high-income strata. We also observed contrasting effects of gender across income-strata on the frequency, duration and type of contacts individuals made.

    Conclusions: These differences in contact patterns between settings have material consequences for both spread of respiratory pathogens, as well as the effectiveness of different non-pharmaceutical interventions.

    Funding: This work is primarily being funded by joint Centre funding from the UK Medical Research Council and DFID (MR/R015600/1).

    1. Epidemiology and Global Health
    2. Medicine
    ISARIC Clinical Characterisation Group et al.
    Research Article

    Background: There is potentially considerable variation in the nature and duration of the care provided to hospitalised patients during an infectious disease epidemic or pandemic. Improvements in care and clinician confidence may shorten the time spent as an inpatient, or the need for admission to an intensive care unit (ICU) or high density unit (HDU). On the other hand, limited resources at times of high demand may lead to rationing. Nevertheless, these variables may be used as static proxies for disease severity, as outcome measures for trials, and to inform planning and logistics.

    Methods: We investigate these time trends in an extremely large international cohort of 142,540 patients hospitalised with COVID-19. Investigated are: time from symptom onset to hospital admission, probability of ICU/HDU admission, time from hospital admission to ICU/HDU admission, hospital case fatality ratio (hCFR) and total length of hospital stay.

    Results: Time from onset to admission showed a rapid decline during the first months of the pandemic followed by peaks during August/September and December 2020. ICU/HDU admission was more frequent from June to August. The hCFR was lowest from June to August. Raw numbers for overall hospital stay showed little variation, but there is clear decline in time to discharge for ICU/HDU survivors.

    Conclusions: Our results establish that variables of these kinds have limitations when used as outcome measures in a rapidly-evolving situation.

    Funding: This work was supported by the UK Foreign, Commonwealth and Development Office and Wellcome [215091/Z/18/Z] and the Bill and Melinda Gates Foundation [OPP1209135]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.