How effective are different types of PPE (mask, gown, gloves)?

Posted on April 20, 2020 by Kelly Dong

Summary

In general, only the combination of PPE (face mask, gown, gloves, eye protection, and face shield) will sufficiently reduce transmission. Inconsistent use missing one of these elements have been associated with higher transmission rates. However, individually, masks, gowns, and gloves have evidence so show that they are independently effective in preventing transmission. On the other hand, there is insufficient evidence behind eye protection and face shields for respiratory viruses. Multiple layers of masks and gowns were not associated with increased protection. 

I.   Overall

  • A combination of N95 respirator mask, gloves, and gowns were associated with a significant decrease in transmission of respiratory viruses: OR 0.09 (CI 0.02-0.35) (1)
  • Inconsistent use of PPE was associated with a higher risk of SARS (OR = 6.78, p≤0.0001) (2)
  • None of the staff who used a combination of masks, gloves, handwashing, and gowns (n=69) became infected with SARS but all the infected staff (n=13) had omitted at least one of these measures (p=0.0224) (3)
  • There is evidence that some healthcare workers were infected with SARS following exposure to aerosol and droplet generating procedures despite wearing full PPE (N95 mask, gown, eye protection, gloves), which was attributed to removing PPE unsafely, reuse of single use PPE, not having masks fitted prior to use, and not using eye protection (4)

II.   Face mask

  • Wearing surgical masks is likely to reduce inhalation of very small droplets by 20 to 30% whereas a disposable respirator certified to an appropriate standard can, on average, reduce the concentration by 95% (5)
  • Staff who wore surgical masks and N95 masks were significantly associated with non-infection, but this was not seen for paper masks (3)
  • Multilayered cotton masks were not associated with protecting healthcare workers (6)
  • Use of a mask is protective compared to no mask and SARS was less likely to develop if a mask was used consistently with each patient contact (4)

III.   Gloves

  • 6 studies showed that gloves were effective in decreasing transmission: OR 0.32 (95% CI 0.23 to 0.45) (7)
  • Wearing two layers of gloves significantly protected health care workers from SARS compared with wearing a single layer of gloves (6)
  • Despite gloves being accepted as the primary measure of barrier precautions, this does not outweigh handwashing and a perceived lack of need by healthcare workers to wash hands if gloved may have resulted in increased transmission of SARS (8)

IV.   Eye protection/face shield

  • Recommended for contact, droplet, and aerosol-generating procedures to avoid contamination of mucous membranes (9)
  • Insufficient evidence for the efficacy of eye protection, as in a retrospective study reported that 70% of healthcare workers in the United States who cared for SARS patients did not use eye protection but there was no documented transmission reported even among those who had been within 3 feet of a confirmed case (10)
  • 26% (n=136) of healthcare workers inappropriately touched the front of their mask while doffing (11)

Questions? Comments? Does this need to be updated? Do you have valuable points to add ? Please email ask.reakt@ubc.ca.

References

  1. Jordan V. Coronavirus (COVID-19): infection control and prevention measures. Journal of Primary Health Care. 2020;12(1):96-7.
  2. Gamage B, Moore D, Copes R, Yassi A, Bryce E, BC Interdisciplinary Respiratory Protection Study Group. Protecting health care workers from SARS and other respiratory pathogens: a review of the infection control literature. American Journal of Infection Control. 2005 Mar 1;33(2):114-21.
  3. Seto WH, Tsang D, Yung RW, Ching TY, Ng TK, Ho M, Ho LM, Peiris JS, Advisors of Expert SARS group of Hospital Authority. Effectiveness of precautions against droplets and contact in prevention of nosocomial transmission of severe acute respiratory syndrome (SARS). The Lancet. 2003 May 3;361(9368):1519-20.
  4. Shaw K. The 2003 SARS outbreak and its impact on infection control practices. Public health. 2006 Jan 1;120(1):8-14.
  5. Semple S, Cherrie JW. Covid-19: Protecting Worker Health. Annals of Work Exposures and Health. 2020 Mar 23.
  6. Chen WQ, Ling WH, Lu CY, Hao YT, Lin ZN, Ling L, Huang J, Li G, Yan GM. Which preventive measures might protect health care workers from SARS?. BMC Public Health. 2009 Dec 1;9(1):81.
  7. Jefferson T, Del Mar CB, Dooley L, Ferroni E, AlAnsary LA, Bawazeer GA, Van Driel ML, Nair S, Jones MA, Thorning S, Conly JM. Physical interventions to interrupt or reduce the spread of respiratory viruses. Cochrane database of systematic reviews. 2011(7).
  8. Yen MY, Lin YE, Su IJ, Huang FY, Ho MS, Chang SC, Tan KH, Chen KT, Chang H, Liu YC, Loh CH. Using an integrated infection control strategy during outbreak control to minimize nosocomial infection of severe acute respiratory syndrome among healthcare workers. Journal of Hospital Infection. 2006 Feb 1;62(2):195-9.
  9. World Health Organization. Infection prevention and control during health care when COVID-19 is suspected: interim guidance, 19 March 2020. World Health Organization; 2020.
  10. Park BJ, Peck AJ, Kuehnert MJ, Newbern C, Smelser C, Comer JA, Jernigan D, McDonald LC. Lack of SARS transmission among healthcare workers, United States. Emerging infectious diseases. 2004 Feb;10(2):217.
  11. Phan LT, Maita D, Mortiz DC, Weber R, Fritzen-Pedicini C, Bleasdale SC, Jones RM, CDC Prevention Epicenters Program. Personal protective equipment doffing practices of healthcare workers. Journal of occupational and environmental hygiene. 2019 Aug 3;16(8):575-81.

Disclaimer

The above is intended to serve as a rapidly-created, accessible source of information curated by medical students and healthcare professionals. It is for educational purposes only and is not a complete reference resource. It is not professional medical advice, and is not a substitute for the discretion, judgment, and duties of healthcare professionals. You are solely responsible for evaluating the information above.