MONDAY, Dec. 3, 2012 (HealthDay News) -- The 2012-2013 flu season is off to an early start, and U.S. health officials warn that it could be a bad one.
The predominant strain so far is called influenza A N3H2. Although not new, it is particularly virulent, which is why this flu season might be severe, according to the U.S. Centers for Disease Control and Prevention.
"This is the earliest regular flu season we've had in nearly a decade, since the 2003-2004 flu season," CDC Director Dr. Thomas Frieden said during a press conference Monday. "That was an early and severe flu year. While flu is always unpredictable, the early nature of the cases plus the strain we are seeing suggests it could be a bad flu year."
"It's time to get vaccinated," he added.
In some areas of the country, flu-like symptoms account for 2.2 percent of doctor visits. At that level, the CDC considers the flu season under way, Frieden said.
Five states are hardest hit right now: Alabama, Louisiana, Mississippi, Tennessee and Texas. Georgia and Missouri are also seeing moderately high levels of flu, Frieden said.
The flu season usually runs from fall through spring, peaking in February.
Fortunately, this year's flu vaccine is an "excellent" match for the circulating flu strains, Frieden said. Based on the usual number of people who get vaccinated, the vaccine should be plentiful, he said.
Currently, 123 million doses of the vaccine have been distributed out of an anticipated total of 135 million doses, he said.
The CDC estimates that 112 million Americans have been vaccinated so far this year, which is about the same as last year, Frieden said.
The CDC urges everyone 6 months and older to get vaccinated. It's especially crucial for pregnant women, children and those 65 and older.
Since infants under 6 months of age can't get the vaccine, their protection is dependent on their mother's immunity. And children, older adults and those with chronic health conditions are at greatest risk for complications from the flu.
In a typical year, some 200,000 Americans will be hospitalized with the flu, and as many as 40,000 will die from its complications -- principally pneumonia -- according to the CDC.
Dr. Marc Siegel, associate professor of medicine at NYU Langone Medical Center in New York City, said influenza A "usually makes for a worse flu season. But it's impossible to predict how severe it is going to be at this stage."
Siegel believes that the greater the number of people who are vaccinated, the less severe the flu season will be. It's called "herd immunity."
"If you want to protect your pregnant wife or your 3-month-old or your asthmatic boy, get your shot," he said. "Create a ring of immunity for both your family and your community. That's the best thing you can do."
To learn more about the flu, visit the U.S. Centers for Disease Control and Prevention.