U.S. government health officials have issued advice about wearing face masks if pandemic influenza strikes, although they warn that the masks are not the first line of defense. VOA's David McAlary reports that in some cases, a face mask is worse than none at all.

Facemask

U.S. health authorities say the guidelines are temporary while studies look into the impact of face masks and the best ways to use them during a flu pandemic. Among the questions being researched is how close do you have to be to an infected person before you are infected?

The U.S. government's disease tracking agency, the Centers for Disease Control, says the studies may take months or years, so in the interim, it is giving its best advice in response to public questions. The agency's director is Dr. Julie Gerberding. "We have been waiting to some extent to try to get the science that we like to have before we issue firm guidelines, but we recognize that people will make decisions for themselves based on their own common sense, so we wanted to get this information out," he said.

The Centers for Disease Control says the new advice is based on the experience in health care facilities. It discusses two types of face protection -- a simple cloth face mask and a respirator -- and each is designed for a different purpose.

The face mask protects against droplets from coughs and sneezes, while a respirator has much finer filters that block about 95 percent of tiny virus particles.

During a pandemic, the mask is recommended for those who have the flu and might come within two meters of others, or for a healthy person who lives with someone with flu symptoms or who will be in a crowd where there might be infected people.

The more sophisticated respirator is designed for healthy people who are in close contact with others known to be infected.

But Gerberding warns against relying on face protection alone in a flu pandemic. "Masks are certainly something that can have a role in personal protection, but they are not the most important thing nor are they necessarily even essential to personal protection. It is important that we not forget the other steps -- to avoid crowds during a pandemic, to stay home if you are sick, and to do everything you can to stay away from people who are ill with respiratory illness during that context," he said.

Gerberding says respirators must fit tightly so unfiltered air does not seep through. They are not recommended for children or men with beards. She notes that a poorly fitting one is virtually no protection, and might give the wearer a false sense of security.

In addition, masks cause faces to sweat more, creating an urge to wipe that might bring flu germs to the face from the hands.

Gerberding points out that the U.S. government is stockpiling millions of masks and respirators for health workers to use during a major flu outbreak, but advises the public and businesses not to hoard them so there will not be shortages.