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.
