US panel wary of mask reuse against pandemic

WASHINGTON (Reuters) - Reusing face masks to fight a shortage in a pandemic such as bird flu is a bad idea even if it might be possible, experts warned in a report on Thursday that highlights a shortage of supplies to fight infectious disease.

The report from an Institute of Medicine committee also underscored how little is understood about transmission of even the most common infections such as influenza.

"There is currently no simple, reliable way to decontaminate these devices (face masks) that would enable people to safely use them more than once," the panel said in a statement.

The U.S. Health and Human Services Department asked the panel to look at the question because of warnings that, in case of a pandemic of influenza, there would soon be a shortage of surgical face masks and fitted masks called respirators.

Experts generally agree that a pandemic of some kind is overdue, and that the H5N1 avian flu virus currently spreading in birds is the most likely threat.

The virus does not easily infect people but it has sickened 204, killing 113 of them. A few mutations could turn the virus into a human pandemic strain that would infect hundreds of millions and possibly kill tens of millions.

Until a vaccine can be formulated, simple hygiene is one of the best ways to protect against the virus. This includes washing hands and, in theory, using protective masks.

The favored mask is called an N95 respirator, because it fits tightly against the face yet allows relatively easy breathing. It is impossible to clean the small particles trapped by the mask out of it, the report said.

Surgical masks are meant to protect others from the wearer but might also be used as a defense. No one has tested either type of mask against flu transmission.

People may be willing to cut corners and expose themselves to flu if using a mask gave them a false sense of protection, said Dr. John Bailar, a professor emeritus at the University of Chicago who chaired the panel.

Dr. Donald Burke, a professor of international health and epidemiology at Johns Hopkins University in Baltimore, said, "Even the best respirator or surgical mask will do little to protect a person who uses it incorrectly, and we know relatively little about how effective these devices will be against flu even when they are used correctly."

The panel said researchers need to determine more precisely how flu viruses spread from person to person.

No one knows for certain whether the virus spreads as an aerosol released in the breath of infected people, spreads on larger droplets projected through coughing and sneezing, or on surfaces, the panel said.