Swine Flu Study on N95 Masks Retracted

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Researchers Revise Earlier Findings Suggesting N95 Masks Are Better Than Surgical Masks at Preventing Flu

By Charlene Laino
WebMD Health News

Reviewed By Louise Chang, MD

Nov. 2, 2009 (Philadelphia) -- N95 masks may be no better than ordinary disposable surgical masks at preventing the flu, after all.

The same researchers who reported in September that only N95 masks offer significant protection against flu now say a reanalysis of their data shows that just isn't true.

Holly Seale, PhD, of the University of New South Wales in Sydney, Australia, presented the updated results on Saturday at the annual meeting of the Infectious Diseases Society of America.

Neil Fishman, MD, an infectious disease specialist at the University of Pennsylvania, says many researchers had been critical of the original findings.

The findings didn't jibe with many doctors' experiences or with findings from a Canadian study showing that N95 masks were no better than surgical masks at protecting nurses against infection, he notes.

Still, the 180-degree turnaround took doctors at the meeting by surprise, Fishman says.

All the research to date has been in health care workers, who are exposed to more bugs than the average person.

From a practical point of view, the new findings are welcome, because ordinary surgical masks are cheaper and easier to find, Fishman says.

The bottom line: Getting your flu shots -- against seasonal and H1N1 swine influenza -- is the best way to protect yourself against infection, experts say.

SOURCES: Infectious Diseases Society of America 47th Annual Meeting, Philadelphia, Oct. 29-Nov. 1, 2009.

Holly Seale, PhD, University of New South Wales, Sydney, Australia.

Neil Fishman, MD, University of Pennsylvania.

Journal of the American Medical Association, online edition, Oct. 1, 2009.

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