FRIDAY, Dec. 3 (HealthDay News) -- Although winter hasn't even arrived, the first signs of flu season have, U.S. health officials said Friday.

In fact, Georgia is seeing a sharp increase in influenza cases, mostly among school-aged children, with the state calling it a regional outbreak. The Georgia cases may be an early sign of what's in store for the rest of the country once flu season really gets under way in the winter, officials from the U.S. Centers for Disease Control and Prevention said.

But there's good news, too: the flu strains circulating so far seem to be a close match for this season's vaccine, experts said, and next week has been designated by the CDC as National Influenza Vaccination Week.

"Flu is coming," Dr. Anne Schuchat, director of CDC's National Center for Immunization and Respiratory Diseases, said during an afternoon press conference. "This fall has begun like so many influenza seasons, with relatively few flu viruses circulating through the end of November."

However, last season's H1N1 flu pandemic was very different from what is usually seen, she noted, and people shouldn't be complacent because flu hasn't roared back yet.

Schuchat noted that this year's flu vaccine is designed to fight the H1N1 pandemic strain, as well as strains H3N2 and influenza B.

In Georgia, influenza B is the strain that is being seen most right now, Schuchat said. "The majority of B viruses from Georgia are related to the B virus that is in our vaccine, so we expect the vaccine to be a good match against this B strain that is already causing quite a bit of disease," she said.

The vaccine is also a good match for the other flu strains seen so far, including H1N1, H2N2 and the influenza B virus, officials said.

Schuchat believes that all Americans, except children under 6 months of age, should get a flu shot. "I strongly encourage people to get vaccinated to make sure you're protected and to make sure your children are protected too," she said.

Children under 9 years of age may need two doses of the vaccine to be protected, Schuchat noted.

Many Americans may be heeding the CDC's vaccination advice this year. "We are encouraged by the number of people who have already received the flu vaccine," Schuchat said.

According to an agency survey, as of mid-November about a third of Americans had already been immunized. Another 15 percent said they planned to get vaccinated and 25 percent said they probably would get vaccinated, Schuchat said. That's about the same as last year, she added.

The highest proportion of people who have been vaccinated are those 65 and older, with about 64 percent of vaccinations occurring among seniors, according to the survey.

In other CDC surveys, the agency found that 56 percent of health-care workers reported having gotten their flu shot. Another 7 percent plan to get vaccinated, Schuchat said.

Among pregnant women -- a group hit especially hard by H1N1 last flu season -- 45 percent said they had already been vaccinated and another 4 percent said they planned on getting the shot.

This year the vaccine is available at record levels, with more than 160 million doses already distributed, Schuchat said.

Speaking at the news conference, Dr. Howard Koh, assistant secretary for health in the U.S. Department of Health and Human Services, said that "flu activity is increasing across the country. If you've been thinking about getting vaccinated for influenza, now is a good time to do so."

The flu is unpredictable and potentially deadly, so everyone should get a flu shot, he added.

Koh noted that under the new Patient Protection and Affordable Care Act, all new health insurance plans will cover flu shots, with no co-pays.

According to CDC estimates, approximately 5 percent to 20 percent of Americans get the flu each year, and more than 200,000 people are hospitalized for flu-related complications. From 1976 to 2006, estimates of flu-associated deaths ranged from a low of about 3,000 to a high of about 49,000 people.

More information

For more on flu, visit the U.S. Centers for Disease Control and Prevention.