CDC Issues Guidelines For Battling Flu Pandemic

Arie Manangan of the Centers for Disease Control and Prevention uses a map to track a mock flu outbreak during an exercise to see how well the CDC would react.
Arie Manangan of the Centers for Disease Control and Prevention uses a map to track a mock flu outbreak during an exercise to see how well the CDC would react. (By John Bazemore -- Associated Press)
By David Brown
Washington Post Staff Writer
Friday, February 2, 2007

ATLANTA, Feb. 1 -- States should be prepared to keep children out of school for three months, businesses should be prepared to operate with skeleton workforces, children should be prepared to play mostly with their siblings, and parents should be prepared to lose income as they skip work and cobble together rickety child-care arrangements.

That was the picture sketched Thursday by federal officials in a guidance for communities on how to fight pandemic influenza in the months before a vaccine becomes available -- if one ever does.

"We have tools in our tool kit that we can use now to slow down pandemic flu," said Martin S. Cetron, the director of global migration and quarantine at the Centers for Disease Control and Prevention, the country's chief public health agency. "These are tools we just are not used to using in recent decades, when all the attention has been on magic bullets."

The 106-page document issued by the CDC outlines "non-pharmaceutical interventions" against a virus that can sometimes be caught simply by standing near an infected person. The chief strategy is to keep people physically apart as much as possible during the eight-to-10-week-long waves of illness.

States and metropolitan areas would decide when to invoke various measures, such as closing schools and banning concerts and sporting events. The guidance, notably, did not suggest restricting travel. Its authors believe that if a pandemic's effects can be blunted or spread out over time, the essential functions of the economy may be able to continue largely unchanged.

Nevertheless, without a vaccine, it will be a scary and dangerous time.

"We don't expect we would be able to protect everybody," the CDC's director, Julie L. Gerberding, said at a news conference here.

Pandemic America would be an old-fashioned place. People would spend most of their time with close relatives and a few neighbors. They wouldn't go to the movies, run to the supermarket on a whim, or hug people they barely know. The sick would be cared for at home unless they were near death. Everyone would shun the houses of the ill.

At the same time, many of today's habits and capabilities would remain.

Many adults would telecommute to work in a season of near-endless "snow days." Children would probably turn in homework over the Internet. Prescription drugs would be prescribed liberally as preventive medicines. A government-woven safety net would probably provide food, personal care and financial assistance to people who couldn't cope on their own.

The use of face masks -- popular during the epochal "Spanish influenza" of 1918 -- wasn't addressed in the "Community Strategy for Pandemic Influenza Mitigation" booklet. CDC planners are still doing research -- both experimental and historical -- to figure out how useful masks might be. They will provide guidance on their use later.

To help states, cities and towns decide when to invoke various measures, the new document outlines a five-category system for estimating a pandemic's danger. The gauge is analogous to the one used for hurricanes, although "case fatality ratio," not wind speed, is the key variable.

Case fatality ratio is the fraction of ill people who die. In the Spanish flu, which killed about 50 million people worldwide, the ratio in the United States was about 2.2 percent. (It was 10 times as high in some other parts of the world.) Spanish flu in modern America would kill about 1.8 million people; it is Category 5.

The case fatality ratio was less than 0.5 percent in 1957 and 1968, the two most recent pandemics, which rank as Category 2. In the current sputtering outbreak of H5N1 "bird flu" in Southeast Asia, the ratio is above 50 percent. But that virus doesn't have the ability to spread easily among people -- the essential feature of a pandemic strain.

Schools are society's most densely populated environments -- in square feet per person, eight times as dense as offices and more than 10 times as dense as single-family homes. In 1918, closing schools was the most effective tool for slowing the virus. Some cities experienced a roller-coaster ride of infection as schools were closed, opened and closed again.

A 2003 study found that children in day-care centers were 2.2 times as likely to get upper respiratory infections as children cared for at home. Day-care centers would be among the first institutions to close. But arrangements in which five or fewer children were cared for by a couple of families might still be safe, the study found.

Cetron warned that ignoring a pandemic's potential for societal disruption is futile. In 1918, schools eventually closed in most American cities, but it was too late in many to blunt the epidemic's mortality.

"It's not like those things are going to go away; we're just going to face them unprepared in a Category 5 event," he said. He added, invoking the memory of Hurricane Katrina, "And we all know what happens when we aren't prepared for a Category 5 event."

© 2007 The Washington Post Company