Ont.Med.Review Health Policy Dept still advises N(NIOSH) 95 (% efficiency) masks in management of MEASLES.

CMAJ. 2003 Sep 16; 169(6): 541–542.

PMCID: PMC191266

SARS respiratory protection

John H. Lange

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Since preparation of my letter on respiratory protection against severe acute respiratory syndrome (SARS) for health care workers,¹ an additional important study has appeared. Ofner and associates² have reported on 9 of 11 health care workers in whom SARS developed even though they were following the infection-control precautions recommended in Canada at the time,³ including use of an N95 respirator. However, the N95 respirator in use was a duckbill mask (PCM2000, Kimberly Clark Health Care, Roswell, Ga.), which is not approved by the US National Institute for Occupational Safety and Health (NIOSH).² The use of N95 respirators, a recommendation adopted from tuberculosis (TB) protection guidelines, has been suggested by the US Centers for Disease Control and Prevention (CDC) for protection against SARS, although the CDC recommends that only NIOSH-approved respirators be used.⁴ Of note, TB bacteria are much larger than the SARS virus, which indicates that a higher-efficiency respirator would be required for adequate protection against the virus.

Ofner and associates² reported that the health care workers in their study were not fit-tested, and at least one of the workers had a beard. In my earlier letter,¹ I suggested N100 respirators with ultra-low penetrating filters for the best protection. The respirator should also be elastomeric to allow a good fit on the face; notably, N100 elastomeric respirators can be cleaned and reused. Before a health-care worker uses a respirator, he or she should receive appropriate training, must be properly fit-tested, and should undergo a medical surveillance examination; these activities should be repeated yearly. In a previous study of asbestos workers,⁵ I reported that many do not use their respirators properly, despite training. Thus, providing N100 respirators will be insufficient to prevent infection if health care workers use them improperly or compliance is less than 100%.

John H. Lange Environmental and Occupational Health Consultant Envirosafe Training and Consultants, Inc. Pittsburgh, Pa.

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References

1. Lange JH. The best protection [letter]. CMAJ 2003; 168(12):1524. [PMC free article] [PubMed]

2. Ofner M, Lem M, Sarwal S, Vearncombe M, Simor A. From the Centers for Disease Control and Prevention. Cluster of severe acute respiratory syndrome cases among protected health- care workers — Toronto, Canada. JAMA 2003; 289:2788-9. [PubMed]

3. Infection control guidance for respirators (masks) worn by health care workers — frequently ask questions. Severe acute respiratory syndrome (SARS). Ottawa: Health Canada; revised 2003 Jun 6. Available: www.hc-sc.gc.ca/pphb-dgspsp/sars-sras/ic-ci/sars-respmasks_e.html (accessed 2003 Aug 7).

4. Interim domestic guidance on the use of respirators to prevent transmission of SARS. Atlanta: Centers for Disease Control and Prevention; 2003 May 6. Available: www.cdc.gov/ncidod/sars/respirators.htm (accessed 2003 Aug 6).

5. Lange JH. A questionnaire survey during asbestos abatement refresher training for frequency of respirator use, respirator fit testing and medical surveillance. J Occup Med Toxicol 1993; 2:65-74.