Study: Surgical masks prevented hospital staff from acquiring H1N1

The effectiveness of ordinary surgical masks as opposed to respirators in protecting health care workers against the 2009 H1N1 influenza virus has been the subject of debate. An observational study published in the April 1, 2010 issue of Clinical Infectious Diseases, available online (http://www.journals.uchicago.edu/doi/full/10.1086/651159), suggests that surgical masks are just as effective as respirators in this regard.

Researchers analyzed the incidence of H1N1 among health care workers from April through August of 2009 at Tan Tock Seng Hospital in Singapore. A small percentage tested positive for H1N1 during this period. None had cared for any patients with H1N1 or worked in H1N1 screening areas of the emergency room. In all cases, transmission was believed to have occurred outside of patient care, when health care workers were in contact with roommates, the general public, and other sources.

From June 19 to July 21, health care workers at the hospital wore N95 respirators in the emergency room and an H1N1 isolation area. From July 22 to Aug. 31, surgical masks were used by workers in these areas. The incidence of H1N1 among workers remained low during both periods. Although the study was observational, the findings suggest that surgical masks and respirators did not differ in their effectiveness in preventing hospital staff from acquiring H1N1.

"What is more important than using high-filtration or respirator masks for known or suspected cases is to have a uniform policy, such as using surgical masks, when in close contact with all patients," said study author Brenda Sze Peng Ang, MD, of the Tan Tock Seng Hospital in Singapore. "This way, health care workers are protected from getting infected by patients not initially thought to have H1N1."