Unmasking the confusion of respiratory protection to prevent influenza-like illness in crowded community settings.

The 2009 novel influenza A(H1N1) (hereafter " nH1N1 ") pandemic has sparked renewed interest in, and controversy regarding , the use of respiratory protection to reduce influenza transmission. Use of masks to prevent influenza generally applies to 2 populations: health care workers (HCWs) providing care for patients with proven or suspected influenza to both protect the HCW and prevent nosocomial transmission to high-risk patients; and persons in certain community settings, such as in households of individuals at high risk for influenza complications. In this issue of the Journal, Aiello et al [1] report on the effectiveness of using a face mask combined with hand hygiene for preventing transmission of influenza-like illness (ILI) in a crowded community setting: college residence halls. The authors should be commended for undertaking this logistically challenging, yet important , endeavor as they have conducted a well-designed, cluster randomized study. College students living in residence halls were randomized to a face mask with hand hygiene (FMHH) group, face mask only (FM) group, or control group. Importantly , all participants, including those in the control group, received information on hand hygiene. All reviewed a basic hand hygiene educational video without specific information on appropriate technique. Participants in both intervention groups (the FMHH and FM groups) viewed additional video on how to properly perform hand hygiene, but only those in the FMHH group received written instructions on proper hand sanitizer use along with a supply of hand sanitizer. Intervention group participants were instructed to wear face masks as frequently as possible when in the residence hall, in addition to encouraging the use of face masks when outside the halls. Of note, the 6-week intervention period began with the first laboratory-confirmed case of influenza among the campus population. Prior studies of community use of respiratory protection only initiated face mask use once an index case of influenza [2] or influenza like illness [3] was identified in the home. Because close contacts in this setting may have already been incubating infection before the initiation of respiratory protection, demonstration of a protective effect of face mask use may be more difficult. As presented by Aiello et al [1], FMHH—when initiated after the first confirmed case of influenza in a com-munity—provided protection against ILI when implemented in crowded residential settings. Participation in both the FMHH and FM-only groups resulted in significantly fewer episodes of ILI than the control group, during weeks 4–5 in …