Are surgical masks as effective as N95 respirators to prevent influenza?

Originally posted in Insidermedicine

Nurses are as well protected from influenza with a standard surgical mask as with an N95 respirator while caring for febrile patients, according to a randomized trial published in the November 4 issue of the Journal of the American Medical Association.

Here are some guidelines for infection control among hospital patients with confirmed or suspected H1N1 influenza, from the Centers for Disease Control and Prevention:

• Respiratory hygiene/cough etiquette infection control measures should be implemented at the first point of contact with a potentially infected person

• Any patients who have a confirmed, probable, or suspected case of novel H1N1 and present for care at a healthcare facilities should be placed directly into individual rooms and the door should be kept closed.

• For procedures that are likely to generate aerosols, an airborne infection isolation room (AIIR) with negative pressure air handling with 6 to 12 air changes per hour can be used.

Researchers out of McMaster University in Hamilton randomized 446 nurses from eight Ontario hospitals to use of surgical masks or N95 respirators for the prevention of influenza. The nurses were instructed to use the masks or respirators while caring for febrile patients between September and December 2008.

During the study period, laboratory-confirmed influenza occurred among 23.6% of nurses assigned surgical masks and 22.9% of those assigned N95 respirators. Non-inferiority of surgical masks was maintained even among nurses with an increased level of the circulating pandemic 2009 H1N1 influenza strain.

Today’s research indicates that surgical masks are as effective as N95 respirators for preventing the spread of influenza, at least in a typical nursing setting.