IE 11 is not supported. For an optimal experience visit our site on another browser.

Flu-fighting masks may help, but don’t bet on it

Face masks are flying off drugstore shelves as the swine flu outbreak widens in the U.S., but health officials are hedging their answer to the question: ‘Do face masks really work?’

It’s the surest sign that an outbreak of illness or infection has grown serious: People on the street wearing face masks as they hurry to work, crowd into the subway or walk their dogs.

Such images have been ubiquitous this week in Mexico, where a swine flu epidemic may have sickened 6,000 and is suspected in more than 150 deaths.

And now, in the U.S., where the new flu strain has killed a 23-month-old child in Texas and been confirmed in at least 93 people in 11 states, worried residents have started stocking up on masks and wondering whether to wear them, especially in places like New York and Texas, where the outbreak appears to be expanding.

But health officials here are hedging answers to the simple question: “Do face masks really work?”

It turns out that protection is possible, but the degree depends on what kind of mask you choose, what kind of environment you're in and how willing you are to use it consistently, experts say.

“The CDC does not have a firm message on this,” said Dr. William Schaffner, chair of preventive medicine at Vanderbilt Medical Center in Nashville, Tenn., and a spokesman for the Infectious Diseases Society of America.

Guidelines posted this week by the federal Centers for Disease Control and Prevention recommend that people avoid close contact and crowded conditions rather than relying on face masks for protection from infection during a flu pandemic. But they also suggest that face masks might reduce risk if it’s impossible to avoid crowds or people who are already infected.

"Very little is known about the benefits of wearing face masks or respirators to help control the spread of pandemic flu," the CDC notes.

The trouble, said Schaffner, is that whether or not face masks protect against viruses such as the swine flu depends greatly on what kind of masks people use and how well they wear them.

There are basically two kinds of face masks: loose-fitting surgical or medical masks made of soft, thin cloth that sell for pennies apiece, and form-fitting masks, also known as N-95 respirators, made of spun plastic fibers that filter small particles. They sell for a few dollars each.

The surgical masks are generally used to protect other people from the cough spray of the wearer, Schaffner said. The respirators are designed to filter 95 percent of tiny particles, including influenza viruses.

“If people were careful about their use and used them consistently, could masks provide some level of protection? I would say ‘Yes,’” Schaffner said.

You could get a false sense of security’
But if any of those conditions aren’t met, people are better off tossing both kinds of masks and avoiding the illusion they’re protected at all, he added.

“You could get a false sense of security,” Schaffner said.

That hasn’t stopped Americans from stocking up on both varieties of face masks as well as other flu-related supplies, retailers and manufacturers say.

An executive with a medical supply Web site told CNBC on Tuesday that a major mask supplier had run out of an entire year’s supply of masks. Valerie Paxton of AllegroMedical.com said the company sold more than 20,000 N-95 respirator masks on Monday alone.

Mask manufacturers, including 3M, Prestige Ameritech and the Kimberly-Clark Corp. have said they are increasing production to keep up with demand.

At Rite Aid stores in New York, New Jersey and California, face masks have sold out in some sites, along with hand sanitizer, antiviral medication and thermometers, said Cheryl Slavinsky, a spokeswoman for the drugstore chain.

“We’ve been shifting stock, moving product from store to store,” she said. “We’ve got plenty in our distribution supplies.”

Those shoppers could see some benefit from their supply of masks, research suggests. A 2006 report by the Institute of Medicine concluded that cloth masks work better than using homemade masks such as scarves. Although using a respirator would be better still.

And a study in The Lancet journal said that use of N-95 masks in the outbreak of SARS — Severe Acute Respiratory Syndrome — gave Hong Kong hospital patients up to 13 times more protection than not wearing one.

Masks must be worn properly, consistently
But in both cases, masks needed to be used along with other preventive measures such as frequent handwashing and staying away from sick people.

The level of protection depended on whether the masks were worn properly — over both the mouth and nose, for instance — and whether they were worn consistently. One problem with the N-95 masks is that although they filter microscopic particles, they also impede breathing, making them uncomfortable to wear for extended periods of time, Schaffner said.

“Those of us who are a little claustrophobic don’t like to wear them for very long,” he said.

Still, using masks in a place with an identified outbreak might make sense, said Barbara Russell, director of infection control at Baptist Hospital of Miami, Fla., and an emergency preparedness expert with the Association for Professionals in Infection Control and Epidemiology.

“If you are in an epidemic center like New York, it probably wouldn’t hurt to have some around,” Russell said. “As far as wearing it to work or wearing it on the street, we’re not there yet.”

One of the biggest benefits of wearing masks during outbreaks of infection or illness might be the psychological boost it provides, Schaffner said.

People who don masks may also wash their hands more frequently, avoid crowds and take more responsibility for safeguarding their health.

“It shifts the locus of control,” he said.  “It makes people think, ‘I’m not just a victim, waiting for the virus to attack me.’”