Will Science and Common Sense Prevail in the N95 Issue?


Editor's Note: This commentary is being published online ahead of print and will appear in the SHEA Synopsis column in the December 2009 issue of Infection Control Today.

In the midst of the resurgent outbreak of novel H1N1 influenza and with the likely appearance of seasonal strains of influenza on the near horizon, we are locked in a debate regarding respiratory protection of healthcare workers that continues to distract us from the larger issue of how best to deal with this evolving pandemic.

At the heart of the controversy is the tug-of-war between the infection prevention and public health community and organized labor and OSHA on how to best protect healthcare workers from H1N1 influenza. Since it became evident this summer that H1N1 influenza behaves like seasonal influenza, the Society for Healthcare Epidemiology of America (SHEA) has taken the viewpoint that standard surgical masks offer adequate protection for healthcare workers in routine clinical settings. A host of other professional societies, the CDC’s Healthcare Infection Control Practice Advisory Committee (HICPAC), the World Health Organization and countless individual hospitals and clinics have concurred with our statement on this issue. 

An Institute of Medicine (IOM) panel that was specifically charged to ignore practical and logistical considerations reached an alternate conclusion and recommended use of fit-tested N-95 respirators for routine care of patients with known or suspected H1N1 influenza. The IOM report, along with heavy lobbying by organized labor, ultimately led to revised CDC guidance last month that favored first-line use of N-95 respirators.

However, a key event occurred last week in Philadelphia at the annual meeting of the Infectious Diseases Society of America (IDSA) that may prompt re-evaluation of the guidance for healthcare worker H1N1 respiratory protection.  More specifically, a group of scientists, based largely in Australia, presented a re-evaluation of their findings from a study conducted in Chinese healthcare workers. In their initial analysis released earlier this fall, the investigators claimed that N-95 respirators provided significantly better protection than surgical masks. This report was widely publicized and was heavily weighted in the IOM panel consideration. 

However, when the data were analyzed more carefully, taking into account the effect of clustering and multiple comparisons, there was no significant difference between N-95 respirators and surgical masks in any of the primary endpoints. Therefore, although N-95 respirators have a greater filtering capacity than surgical masks, in clinical use, they do not appear to offer greater protection from acquisition of influenza among healthcare workers.

This is the same conclusion that was reached in a study from investigators in Toronto (Loeb et al., JAMA, 2009).  Two lessons should be learned from this experience.  First, it is important for the scientific process to occur free of outside influence from politics or organized labor. Second, it is ill-advised to rely upon preliminary reports until they have stood up to rigorous peer review.

As these events unfold, the SHEA approach -- careful and impartial examination of the evidence and the formation of policy and practice based on both science and well-informed clinical and practical experience – offers healthcare institutions a clearer guidepost. 

The downside to all of this controversy has been to distract institutions from adherence to those measures that we know will pay off:

1. Early recognition and triage of patients with influenza-like-illness

2. Respiratory etiquette and cover-your-cough programs

3. Promotion of hand hygiene

4. Exclusion of ill visitors and healthcare workers from the hospital

5. Most importantly, universal influenza vaccination

In another twist of logic, some of the same groups that so adamantly favor N-95 respirators vociferously oppose universal influenza vaccination for healthcare workers. This just doesn’t add up.  Why refuse the measure that is proven to be the best means to prevent influenza – vaccination, and at the same time demand the use of N-95 respirators that, in routine clinical situations, don’t offer any added protection over surgical masks? Only time will tell whether science and common sense prevail in the debate on healthcare worker respiratory protection from H1N1 influenza. The scientific evidence and clinical experience presently available heavily favor vaccination and practical infection control measures over reliance on N-95 fit-tested respirators.

Mark E. Rupp, MD, is president of the Society for Healthcare Epidemiology of America (SHEA) and is professor in the Department of Internal Medicine, Section of Infectious Diseases at the University of Nebraska Medical Center.




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