Study finds inadequate mask use among health care workers early in 2009 H1N1 outbreak

Inadequate use of masks or respirators put health care workers at risk of 2009 H1N1 infection during the earliest stages of the 2009 pandemic in the U.S., according to a study published in the December issue of Infection Control and Hospital Epidemiology, the journal of the Society of Healthcare Epidemiology of America.

The study, led by the Centers for Disease Control and Prevention (CDC), tracked 63 Southern California health care workers who had contact with six of the first eight laboratory-confirmed 2009 H1N1 cases in the U.S. Because these contacts happened before the 2009 H1N1 outbreak had been widely reported, the cases shed light on how well health care workers protect themselves before a direct epidemiological threat becomes evident.

The investigation found that 9 of the health care workers tracked became infected with the 2009 H1N1 virus, likely from contact with infected patients. Twenty of the 63 health care workers reported that they had worn a mask or respirator at least once when in contact with patients, and no one from that group became infected with 2009 H1N1. Meanwhile, 43 workers reported never using a mask around patients, and all 9 infections occurred in workers from this group.

Overall, mask and respirator use was disappointingly low, the researchers report. Only 19 percent reported using a mask during every patient encounter. Use was especially low among outpatient workers, who also made up the majority of those who became infected with 2009 H1N1.

"The findings highlight the challenge of getting health care personnel to routinely wear Personal Protective Equipment," Jenifer Jaeger, MD, MPH, Associate Pediatrician, Massachusetts General Hospital, said. "The study also suggests that greater attention to infection control and preparedness, particularly among outpatient workers, is needed."