University of New South Wales (MacIntyre) Study on Healthcare Worker Respirator Use

November 9, 2009

Results of a randomized trial of health care personnel respirator use were presented by The University of New South Wales (Australia) group (MacIntyre and colleagues) at the Infectious Diseases Society of America (IDSA) meeting October 31. New relevant scientific information such as this is assessed as to whether it would affect the U.S. Centers for Disease Control and Prevention's (CDC) Interim Guidance on Infection Control for 2009 H1N1 Influenza in Health Settings, Including Protection of Healthcare Personnel. http://www.cdc.gov/h1n1flu/guidelines_infection_control.htm

The IOM panel explicitly stated that it did not rely on the MacIntyre study in issuing its recommendations (http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=12748 ), nor is the IOM Report or this study mentioned in the CDC Guidance. In presenting the results of the IOM letter report to the sponsors of the review, CDC and OSHA, Dr. Ken Shine, the panel chair, made a point of specifically saying that the two recently-conducted randomized trials of respirator use, the MacIntyre and the Loeb studies, were not considered in the committee's decision.

The pertinent paragraphs from the CDC Guidance are below:

Recommendation: CDC continues to recommend the use of respiratory protection that is at least as protective as a fit-tested disposable N95 respirator for healthcare personnel who are in close contact with patients with suspected or confirmed 2009 H1N1 influenza. This recommendation applies uniquely to the special circumstances of the current 2009 H1N1 pandemic during the fall and winter of 2009-2010 and CDC will revisit its guidance as new information becomes available, within this season if necessary.

Basis: The current recommendation is based on the unique conditions associated with the current pandemic, including low levels of population immunity to 2009 H1N1 influenza, availability of vaccination programs well after the start of the pandemic, susceptibility to infection of those in the age range of healthcare personnel, increased risk for complications of influenza in some healthcare personnel (e.g., pregnant women), and the potential for healthcare personnel to be exposed to 2009 H1N1 influenza patients because of their occupation.

Future Plans

As noted above, scientific evidence for the CDC guidelines, and the public health context for guidelines and recommendations, are continually reassessed, and the guidance is updated as needed to reflect current situations.

Additional data are needed to more clearly determine 1) the modes of transmission of influenza, 2) factors that affect the risk of infection (such as the medical procedures being performed and the distance between the worker and the patient), and 3) the most effective methods for protecting healthcare personnel and patients from acquiring influenza infection in the healthcare setting. There are a number of studies that are underway or being planned at CDC and elsewhere which should help address these issues. As a sufficient body of new data becomes available, NIOSH and CDC will evaluate those data, and will consult with external experts and a variety of stakeholders regarding how the new data should affect the CDC guidance.

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