Flu doesn't stop at the border

Many countries are still ignoring the advice of the World Health Organization, which is discouraging border closures and travel restrictions because it is convinced that containment of swine flu is no longer feasible and instead favors basic prevention measures like hand washing.

"Containment is no longer a feasible option," Dr. Keiji Fukuda, WHO's deputy director general, said in Geneva on Monday after a meeting of the agency's emergency committee on the spreading swine-flu virus.

Since then, the world has become a confusing welter of bans, advisories and alerts on both pork and people.

On Wednesday, Homeland Security Secretary Janet Napolitano was pressured in congressional hearings to ignore the advice and close the border with Mexico. She defended her decision not to do so, saying it "would be a very, very heavy cost for what epidemiologists tell us would be marginal benefit."

Experts on the global movement of flu say Napolitano and Fukuda are right. The world, they say, must bow to the inevitable: Closing borders would not stop the virus because borders are porous, and doing so would cause enormous economic disruption and possibly add to the death rate.

"But it's wrong to think we're throwing up our hands and saying, 'Let 'er rip and let's hope for the best,' " said Dr. Martin Cetron, director of global migration and quarantine for the Centers for Disease Control and Prevention (CDC). "This has all been in the national pandemic-flu plan since 2007."

Closing borders is dangerous because many goods needed in a pandemic are made abroad, said Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, including most masks, gowns and gloves, electrical circuits for ventilators and communications gear and pharmaceutical drugs and the raw materials to make them. (For example, most suppliers of shikimic acid, the base ingredient for Tamiflu, are in China.)

"You cut those off and you cripple the health-care system," he said. "Our global just-in-time economy means we are dependent on others."

The fallback position, experts said, is mitigation, the use of "nonpharmaceutical measures." They include personal ones such as washing hands and wearing a mask, occupational ones such as working from home, neighborhood-level ones such as closing theaters, museums or restaurants, and metropolitanwide ones such as shutting a school system or canceling a baseball game.

For WHO, mitigation is an about-face from the strategy that has contained the H5N1 avian flu, which has caused fewer than 300 deaths.

That flu's first appearance in 1997 was contained by killing every chicken in Hong Kong. Since then, each time a cluster appears — many of them in rural villages — public-health authorities try to cull all the local poultry, vaccinate birds in a large ring around that and drop the "Tamiflu blanket" on people — dosing everyone in the area.

The 1976 swine flu also was beaten by containment, said Dr. Pascal Imperato, dean of the school of public health at the State University of New York Downstate Medical Center, who was the chairman of the New York City Swine Flu Task Force in 1976.

The 230 cases were all among soldiers at Fort Dix, N.J., "and they were all just held within that base," he said. "They had no external contacts. One died; the rest had mild infection."

Travel bans were effective during the 2003 outbreak of SARS in Asia, because that illness can be transmitted only by people who already show symptoms. With flu, by contrast, the incubation period ranges from 24 hours to four days.

The World Health Organization said total bans on travel to Mexico were questionable because the virus is already fairly widespread.