New Guidelines On N95 vs Surgical Masks

Mon, 11/02/2009 - 4:50am

According to a recent release from the Infectious Diseases Society of America, authors of a study that found N95 respirators were better than surgical masks at preventing the flu have retracted many of their findings. After a re-analysis prompted by questions from reviewers, the findings were no longer significant, said Holly Seale, PhD, of the University of New South Wales in Sydney, Australia.

The original study, presented earlier this year, formed the basis of several important policy decisions, including CDC guidance on the use of masks in a health care setting. The retraction was made near the end of a presentation at the annual meeting of the Infectious Diseases Society of America.

“The findings appeared to differ – not only from previous reports, but also from the abstract submitted to this meeting,” noted Andrew Pavia, MD, of the University of Utah. Seale acknowledged those differences and agreed that the original results no longer stand.

The retraction took some experts by surprise. The study was first presented in San Francisco earlier this year and led to important policy decisions in the U.S. Among other things, it influenced an Institute of Medicine recommendation that health care workers caring for flu patients should use the more expensive N95 respirators.

A Canadian study in the Journal of the American Medical Association in October found no difference between fit-tested N95 masks and surgical masks. The analysis, led by Mark Loeb, MD, MSc, of McMaster University in Hamilton, Ont., was a randomized trial among nurses in eight tertiary care hospitals in Canada. In contrast, the Australian study, conducted in China, was a cluster randomized trial in which the unit of analysis was the hospital.

On the web: Infectious Diseases Society of America


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