Personal Protective Equipment and Influenza
Thursday, August 13, 2009 at 03:10 PM EDT
An unpublished study of respiratory protection in hospital workers in Beijing compared the effectiveness of surgical masks, fit- and non-fit tested N95 respirators in conferring protection from clinical respiratory illness, influenza-like illness, and laboratory confirmed influenza. Surgical masks were not effective, while those wearing N95 masks had 75% protection against influenza. Whether the N95 was fit-tested or not made no difference.
Also discussed were the findings of a published comparison of surgical masks and P2 respirators (similar to N95) in Australian homes in which a child had respiratory illness. There was a four-fold reduction in clinical illness for individuals wearing either mask. Slides describing the Beijing and Australian findings are available as a pdf.
In another study in Hong Kong, households were divided into three groups. One group was given only basic health education, while the second group was told to practice hand hygiene with soap and an alcohol hand rub. The third group of households used hand hygiene and surgical face masks. The investigator concluded that â€œsubstantial and significant benefits of face masks and hand hygiene if implemented within 36 hours of index case symptom onset.â€ The slides from this presentation are available as a pdf.
Here is information from the Food and Drug Administration on N95 face masks:
What does all this mean? If you wear an N95 properly and continuously, it will confer some protection against respiratory infection. But it wonâ€™t help if you poke a hole in the N95 to enable cigarette smoking.
MacIntyre, C. (2009). Face Mask Use and Control of Respiratory Virus Transmission in Households Emerging Infectious Diseases, 15 (2), 233-241 DOI: 10.3201/eid1502.081167
This article originally appeared on virology blog.