Unmasking the truth

Updated 6 April 2007

Wearing an N95 mask will not prevent you from getting influenza, and buying multiple masks for every employee in your office as a pandemic preparation is just…blowing money.

A mask will prevent someone in your office who is sneezing or coughing from spraying snot, saliva and 'germs' on you and your colleagues, by trapping mucus inside his or her mask.

In an office, masks are for the sick people, not for the well people. How many sick people will you knowingly let into your office in an influenza pandemic? Zero. You don't need any masks for them.

How many sick people will you unexpectedly have in your office in the next 12 months? I've said in a previous post that my best guess is that about 20 percent of your headcount, including visitors and vendors, will catch the flu in the next year. Your company could buy masks for those people, so long as everyone understands those masks are for show more than for preventive disease control.

If someone in your work environment is sneezing or coughing, in peace time or in a pandemic, the proper preventive action against any infectious disease is to keep the person out of the office. If she is already in the office and displays symptoms of influenza or a common cold, you should hand her a mask and then send her out of the office. To a doctor. Or to a clinic. Or a hospital. Or to her home.

Then wash your hands with anhydrous, antiseptic hand sanitizer. But you don't need a mask.

Of course, a "respirator" (mask) can keep a wearer from inhaling chunks of airborne contaminants. For an N95 mask, a "chunk" is anything larger than .3 microns--like mucous droplets from someone's sneeze, hydrocarbon exhaust from trucks and motorcycles, smoke particles for those exposed to haze from Indonesia.

But not H5N1 virus particles, which are .1 microns in diameter.

My dentist wears a mask over his nose and mouth while he cleans my teeth. He doesn't do so to keep himself from inhaling my saliva, blood or halitosis (although his mask may stop all three). He does so to keep from exhaling into my open mouth.

To protect himself from me, he wears a full-face, Lexan shield, which prevents my projectile expectorations from spraying into his eyes, nose or mouth. If you really want to protect your employees from projectile expectorations, buy them full-face shields. But I don't guess anybody will wear one.

For prevention, the most effective prophylaxis is having the annual influenza vaccine injection--a "jab", as we say here in Singapore. Masks are only necessary when vaccinations and other precautions have failed.

I know that in an influenza epidemic--or when one is expected imminently--employees will ask for masks no matter what you tell them, thinking that wearing masks will keep them from breathing in viruses. You don't want to refuse if you can help it, so a modest supply of disposable masks seems a prudent precaution.

For most companies, their first purchases of masks will also be their last. Most companies haven't stocked or distributed masks to employees in the past, although influenza contagion is as recurrent and predictable as snow flakes in winter.

You can have all the masks you like, but you can bet most people won't wear them. I know from experience that wearing one is uncomfortable. It's impossible to eat, drink, talk on the phone or kiss your spouse while wearing one. That's the main reason I think that discussion about wearing masks in a business office is mostly hot air.

April 2007 Update A U.S. Centers for Disease Control report on public use of N95 respirators after Hurricane Katrina (for protection against mold) found that 75% of the people didn't wear them properly, negating their effectiveness. end of update

How overwrought is mask mania? I received an e-mail recently wondering if employees should pass a "pulmonary test" before donning a disposable, paper face mask. The inquiry must have come from America, where 30 percent of the people are obese and therefore in danger of having heart attacks. In my opinion, they are at much greater risk of dying of hypertension or hypercholestemia than of bird flu. Masks are unlikely to help or hurt anyone in normal health.

Influenza comes every year. Did your company buy and hand out N95 masks last year during 'flu season'? If they didn't think it worthwhile to distribute masks to employees last year, it isn't any more worthwhile this year than last.

Besides, if you just wait long enough, I predict that companies that stockpiled hundreds or thousands of masks at inflated prices will eventually unload them at bargain prices--on eBay.

Postscript: My comments apply to individuals in an office or commercial work environment. Doctors, nurses and emergency workers must wear masks and nitrile gloves to protect themselves from potential biohazards in the air and on surfaces in hospitals and clinics, where such hazards are legion and ubiquitous. I do not believe that office workers will accept the same precautions, nor that they have reason to do so, even in an infectious disease pandemic.