Medical Masks and the H1N1 Virus

pct1981,

There are two issues (and therefore, two answers):

What kind of mask will protect a wearer from exposure to airborne influenza aerosols?; and

What kind of mask should a sick, infectious person (i.e., a "patient") wear, in order to protect others in close proximity to them from potentially infectious aerosol droplets released by the patient's coughing/sneezing ?

As important as, if not more important than the respirator's efficiency ratings (i.e., N-95, N -100, etc.) is the presence or absence of an exhalation valve.

If you are healthy, and want to minimize your exposure to aerosol droplets released by people who have the flu, you want a mask equipped with one of these to improve comfort, as it allows the wearer's exhaled breath to pass through a flap valve, relatively unimpeded (and unfiltered), while inhaled air passes through the mask's filter media.

That's OK if your exhaled breath is not laden with influenza virus. But if you are sick, a mask equipped with an exhalation valve offers virtually zero protection to other people nearby.

The US Centers for Disease Control (CDC) issued revised recommendations regarding use of facemasks/respirators for protection from the influenza yesterday.

(I receive daily e-mail updates from the US Dept. of Health & Human Services)

You can find that info here: http://www.cdc.gov/h1n1flu/masks.htm

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Disposable respirator with an exhalation valve (above), and

without an exhalation valve (below)

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Just my $0.02...