WASHINGTON (AP) – How to ration scarce medications and speed vaccine production are among the government’s top concerns as it struggles to get ready for the next worldwide flu epidemic, say federal plans obtained by The Associated Press.

But tried-and-true ways of limiting infection such as school closures, travel restrictions, even quarantines may offer the earliest protections when the next pandemic strikes, say the long-awaited plans.

Specialists say it’s only a matter of time before a powerful new flu strain spurs another pandemic. There have been three in the last century, the worst in 1918, when the so-called Spanish flu killed more than half a million Americans and more than 20 million people worldwide.

Concern is rising that the next pandemic could be triggered by the recurring bird flu in Asia, if it mutates in a way that lets it spread easily among people.

“We’re all holding our breath,” Dr. Julie Gerberding, head of the federal Centers for Disease Control and Prevention, said in an interview Wednesday.

About 36,000 Americans die from regular flu every winter. Pandemics strike when the easily mutable influenza virus shifts to a strain that people have never experienced before.

It’s impossible to predict the next pandemic’s toll, but a bad one could kill up to 207,000 Americans, says the Pandemic Influenza Response and Preparedness Plan. Millions more would swarm doctors’ offices and already overcrowded hospitals.

Dr. Robert Couch of the Baylor College of Medicine said doctors have long been urging the government to take two of the steps now planned – stockpiling anti-flu drugs and finding ways to speed vaccine development.

The plan encourages the creation of “seed strains” of worrisome flu types as potential vaccine candidates. If one matches an emerging pandemic strain, it might shave a few months off the typical six to eight months it now takes to brew a new flu vaccine, explained Dr. Anthony Fauci, the National Institutes of Health’s infectious disease chief.

Consider it an insurance policy, said Dr. William Schaffner of Vanderbilt University, who advises the government on flu vaccine policy. “It may never happen, but each year we have to pay the premiums.”

The Pandemic Influenza Response and Preparedness Plan, to be formally released Thursday, is a first draft, open for public comment through October. The Health and Human Services Department particularly wants input on the sensitive question of how to ration scarce vaccines and anti-flu drugs during such a crisis.

Doctors, police and firefighters may be just as important to treat early as frail patients in order to ensure health care is even available and to minimize disruption of public safety and other infrastructure, the plan notes.

Other preparations are under way:

-Federal health officials are pushing states and hospitals to determine now how they would free up hospital beds and conduct triage on the worst flu sufferers. Only a quarter of states had specific plans in place last year.

-Four drugs can treat the flu if given soon after symptoms begin, and decrease chances of catching it. HHS has stockpiled enough doses of one, Tamiflu, to treat 1 million people, because it’s considered the top choice for a pandemic, said Dr. Bruce Gellin, the National Vaccine Program’s director. While supplies are limited, the government is seeking more.

However, a small Japanese study, being published this week in the British medical journal The Lancet, suggests flu strains are becoming more resistant to Tamiflu treatment than previously thought. Mutations against Tamiflu-like drugs were found in 18 percent of 50 children tested, the University of Tokyo research found.

-First on the list of potential pandemic vaccine candidates is the bird flu, which has killed 27 people in Asia this year and prompted destruction of 100 million poultry. Although this H5N1 flu has struck periodically for a few years now, “we’ve never seen so many birds infected with this virus at one point in time,” Gerberding said Wednesday.

The NIH is funding production of a few thousand doses of experimental H5N1 vaccine; safety testing is set to begin in November.

-The CDC is increasing surveillance to better spot dangerous flu strains as soon as they emerge anywhere in the world, providing an early warning.

Ultimately, “good, old-fashioned isolation and quarantine have a special role to play,” CDC’s Gerberding said – something she wants the public to understand before a pandemic hits.