Sales of over-the-counter drugs to treat the flu may help the government more quickly spot local outbreaks. The government now receives figures representing 80 percent of sales of remedies for cold symptoms and diarrhea, for example, in an effort to spot disease trends.

A sudden spike in sales of those products "might be a hint that flu is emerging," the director of the Centers for Disease Control and Prevention (search) told reporters Sunday.

"It's a clue. And we don't know if it's going to be a useful clue or not," Dr. Julie Gerberding said during the American Public Health Association's (search) annual meeting. "We're just learning this year."

The experiment comes as the United States struggles with a shortage of flu vaccine caused by contamination problems at a Chiron Corp. plant in Britain, where 48 million doses destined for the United States were quarantined.

This year's flu season appears to be starting slowly, Gerberding said. Twenty-eight states are reporting cases, including Texas and two New York nursing homes. Not one is reporting widespread flu activity. The remainder of states and the District of Columbia, however, have not recorded a single flu case.

"We're not getting off to a fast start," she said, adding that that did not mean this year's season would remain light. "Flu is so unpredictable. I'm not making any projections, whatsoever," she said.

Through increased production at plants other than Chiron's in Britain, the government has obtained more than 60 million doses of vaccine. U.S. officials had hoped to supply 100 million doses this year.

Food and Drug Administration (search) inspectors are visiting plants in Germany and Canada in pursuit of more flu vaccine.

When the crisis first began, Gerberding said she told her team she wanted three things:

— breakdowns, by county, where flu was spreading. The drug sales may help give an earlier glimpse than waiting for hospitals to fill with the sickest patients.

— where vaccine arrived, by county.

— areas where sick people needed vaccine but supplies had not arrived.

As Americans scramble for scarce doses of flu vaccine, the nation's top public health agency has another worry: bird flu, which Gerberding says people are not particularly focused on.

"We are. And we are very concerned," Gerberding said.

Her agency is monitoring the spread of avian flu in Asia where the deadly virus continues to leap from animals to humans to gauge whether the strain is evolving.

"We have to stay on top of the strains," she said.

Despite the culling of millions of birds, the H5N1 strain of bird flu resurfaced this year. So far, bird flu has killed 20 people in Vietnam and 12 in Thailand.

Under a contract with the National Institutes of Health (search), Chiron is producing vaccine that targets the H5N1 bird flu strain. In addition, the government awarded the Emeryville, Calif.-based company $1.194 million to develop up to 40,000 doses of vaccine against the H9N2 avian influenza. That is a less lethal but more widespread than the strain coursing through Asia.

The government is scheduled to conduct clinical trials using both bird flu vaccines as early as 2005.

In the meantime, however, the CDC will not cordon off its supply of antivirals most effective against avian flu to use solely for that health concern.

Of 40 million doses of antivirals available this year to treat regular flu — reducing sickness among those infected and protecting the healthy — 7 million are in the CDC stockpile.

Gerberding said oseltamivir (search), the antiviral treatment that has proved best at protecting against avian flu, would be used to treat regular flu if the need arose.

The conference where Gerberding spoke attracted more than 10,000 health officers to discuss such matters as smoking, lead poisoning, influenza and obesity.

She said obesity was having a "catastrophic impact" on Americans' health and that three states now report that one-quarter of their citizens are obese.

Employers can help spur people to exercise, enticing people to use stairs by hanging art and piping music into stairwells.

"We know that turning off a couple of elevators works, too," Gerberding said.

California's top health officer, Dr. Richard Jackson, has gone as far as lobbying Hollywood directors to include public health messages in scripts for movies and popular television shows.

Then there is the idea of taxing each teaspoon of high fructose corn syrup in food; the sweetener is linked to the rise of obesity among children. A typical can of soda contains 10 to 12 teaspoons of the ingredient, Jackson said.