(USA Today) -- Pregnant women are among several groups who should get pandemic flu vaccine as soon as it becomes available this fall, the government's leading vaccine advisory group ruled Wednesday.

The panel also placed a top priority on vaccinating parents and other caregivers of infants; health care workers and emergency medical personnel; all children and young adults; and all non-elderly adults with chronic medical conditions.

The Advisory Committee on Immunization Practices issued the recommendations Wednesday in Atlanta as part of an effort to blunt an expected resurgence this fall of pandemic H1N1 flu, also known as swine flu.

Federal health officials usually adopt the panel's recommendations. They are part of an evolving effort to respond to two waves of flu -- swine and seasonal -- expected to hit at about the same time.

Anthony Fiore, a flu expert at the Centers for Disease Control and Prevention, says the panel "did a good job of weighing the evidence and considering the practical issues."

All five of the world's flu vaccine manufacturers have wrapped up production of seasonal flu vaccine and are beginning tests of a new pandemic flu vaccine. Because of the late start, the new vaccine may not be ready for weeks and may not initially meet demand, Fiore says.

The government estimates that, if all goes well, about 120 million swine flu vaccine doses will be available by late October. About 160 million people are in the target groups considered most susceptible to infection or most likely to suffer severe disease.

Vaccine supplies may be limited further by the need to give people two doses, Fiore says. Manufacturers are testing ways of chemically boosting the vaccine's potency, something that's not needed with seasonal flu. The recommendations may change if these so-called adjuvants are used.

Despite these challenges, government officials expect ample supplies, because fewer than half of those who might benefit most from vaccination roll up their sleeves. Only about 15% of pregnant women are vaccinated each year.

Flu experts cautioned about setting narrow priorities, because health workers risk wasting vaccine by holding it in reserve for small priority groups. "The only sin is vaccine left in the refrigerator," says William Schaffner of the Infectious Diseases Society of America.

Missing from the target groups are people 65 and older, a group usually considered crucial candidates for flu vaccination. That's because early studies show that the new pandemic H1N1 virus is taking a bigger toll on young people than the elderly, who suffer more from seasonal flu. As a result, health officials urge older people to get their seasonal flu shots, to be followed by pandemic flu vaccine when supplies become available.

(c) 2009 USA TODAY