In a Pandemic, Authorities Face Daunting Tradeoffs

Inside a pandemic flu simulation at CDC headquarters in Atlanta.

Leading public health authorities worked through a 48-hour pandemic flu simulation recently at the Centers for Disease Control and Preventions' Emergency Operations Center in Atlanta. Richard Knox/NPR hide caption

itoggle caption Richard Knox/NPR

It's near the end of a 48-hour simulated flu pandemic. The Centers for Disease Control and Prevention's top brass are packed into a conference room glassed off from the hubbub of its Emergency Operations Center at CDC headquarters in Atlanta.

It's a chance to practice decision-making in case of a real pandemic. The gathered staff are discussing how to screen all international travelers for flu symptoms.

CDC director Julie Gerberding interrupts.

"I have a question," she says. "Just what is our containment strategy in Pea Ridge?"

She's talking about an actual place — Pea Ridge, Ark., population 2,346. But according to this fictional scenario, a dangerous new strain of Asian bird flu has found its way halfway around the world to Pea Ridge.

The scenario-writers have given Pea Ridge a small expatriate community from the Marshall Islands in the South Pacific. In the pretend pandemic, a Marshall Islander gets infected with the new flu in Indonesia and brings the virus back to Pea Ridge. That's the kind of thing that can happen when air travel is so fast that people can fly from anywhere to anywhere else before they develop flu symptoms.

In this recent CDC simulation, Gerberding needs to find out what's being done to stop the virus from spreading beyond Pea Ridge.

"We've asked the question even this morning of the Arkansas health officials and I don't think we actually know what the containment strategy is in Pea Ridge," Gerberding says.

Her question crystallizes a central issue in how to control a nascent pandemic once a new flu strain has penetrated this nation's borders.

Should most effort be directed at containing the spread of domestic flu cases? Or should the main emphasis in the early days be to prevent more infected people from bringing the virus in?

The recent exercise shows there's no clear answer – and much behind-the-scenes controversy.

When the Pea Ridge cases came to light, on Day 2 of the mock pandemic, CDC officials momentarily considered setting up a cordon sanitaire around Pea Ridge to prevent the spread of flu. Nobody would be allowed to leave or enter the community. That can work when a particular outbreak is small and isolated.

But no decision was made. Without further discussion, Pea Ridge dropped off the CDC's radar screen. Under CDC doctrine, control of domestic outbreaks is left to state and local officials.

Gerberding later asks what happened to the cordon sanitaire idea.

"There's just no legal authority," a staffer tells her. Instead, Arkansas officials are asking people in Pea Ridge who might have had contact with flu cases, or contact with the contacts of cases, to quarantine themselves voluntarily.

While CDC hopes for the best in Arkansas, staffers in Atlanta scramble to set up an emergency system to screen all incoming travelers who might be bringing the new virus into the country. According to the scenario, the World Health Organization calls on the United States to screen outbound travelers too, [because] the new flu has shown up in six states – chains of transmission initiated by a student who brought the virus from Indonesia.

But screening travelers for signs of flu is easier said than done.

Simultaneously setting up two screening programs – one for incoming travelers, one for those who are outbound – is well-nigh impossible, CDC officials say. They decide to appeal the WHO directive.

"We have to convince WHO that we know what we're doing and that it's working," Gerberding says. "And not only WHO, but the rest of the world."

At first, CDC officials recommend that all international flights be funneled to 20 U.S. airports. But staffers figure out it would take several thousand trained workers to carry that out. This cadre doesn't exist. People would need to be pulled from various federal and state agencies, and then trained. The government would also need to buy thermal scanners – machines that spot people with a fever. There's no warehouse where sufficient numbers of these devices sit, waiting to be deployed.

CDC officials decide the best they can do is set up screening programs at 10 selected airports serving about half the incoming travelers. And that will take at least four days to set up.

Meanwhile, thousands of travelers would be entering the United States from southeast Asia.

In a real pandemic, the chances that some of those incoming travelers carry the virus would be considerably higher than in this simulation. According to the fictional scenario, the only countries with known infections in the early days are Indonesia, the United States and the Marshall Islands. That's implausible, Gerberding admits. By the time the virus was seeded in America it would also be showing up in many countries.

Flu moves fast.

For that reason, two research teams funded by the U.S. government to "model" the spread of a pandemic virus have independently concluded that border screening would be futile. "It would be a colossal waste of time and effort," says Ira Longini of the University of Washington, who leads one of those research teams.

CDC officials know about those studies. They even agree that border screening will fail to keep infected people out of the country —- or prevent infected Americans from carrying the virus abroad.

But Gerberding says the "best minds" at the CDC and WHO have concluded that border screening would "buy time." They believe it would slow down the spread of flu, giving the United States and other nations more time to prepare for the onslaught. Border screening would stop when it became clear that more cases of flu were spreading within the country than were being imported from abroad.

Gerberding acknowledges that border screening would also address public pressure on health officials to do something bold and visible to counter the pandemic threat right away.

But when the clock is ticking on a real pandemic, and resources are limited, some may question the wisdom of putting the main emphasis on screening travelers – if it means neglecting opportunities to contain the virus that has already arrived in Pea Ridge and other communities.

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