Nov. 14 (HealthDay News) -- She has won a Golden Globe (for Alias) and the heart of husband Ben Affleck. But actress Jennifer Garner's big concern this flu season is to protect the health of the couple's 2-year-old daughter, Violet.

"One in three children get influenza, and more than 100 children die every year from this disease -- these are facts that no mother or parent wants to hear," said Garner, 35.

She spoke to reporters in New York City on Monday as the new national spokeswoman for the American Lung Association's Faces of Influenza education campaign.

"I want to help make sure that all moms across the country understand that influenza is serious and that vaccination should be a family priority," said Garner, who moved to big-screen stardom in films such as Daredevil, 13 Going on 30 and Catch and Release, and is currently debuting on Broadway opposite Kevin Kline in Cyrano de Bergerac.

Garner is just one of a number of Americans, famous and non-famous, who are lending their voices to the Faces of Influenza campaign. Actor Dean Cain, 41, who soared to fame as TV's Superman in Lois & Clark in the 1990s, was also on hand to urge people to get the flu shot this year.

Cain, a former pro footballer, said even healthy adults can be laid low by the virus. He's especially vulnerable, because he also has asthma, he said.

"Asthma puts me in a high-risk group, because if I were to get the flu, guess where it's going -- right to my lungs," Cain said. A prior bout of flu once left him unable to work for almost two weeks, he said, but "my number one concern is the health of my family" -- specifically, son Christopher, age 6.

That's because children aged 6 months to 6 years of age remain especially vulnerable to flu, according to Dr. Norman Edelman, chief medical officer at the American Lung Association. Other high-risk groups include the elderly, but all Americans over 50 are urged to get an annual shot, as are people with chronic illnesses, Edelman said.

Add to that the people who come in close contact with either the very young and/or elderly, and that means that two-thirds to three-quarters of all Americans -- about 220 million people -- should get vaccinated against the flu, he said.

"But we don't reach anywhere near that," Edelman noted. "We have perhaps just one-quarter to one-third of Americans who get the flu shot."

One common myth: That if you don't get the shot by Thanksgiving, it's already too late. "It only takes about two weeks for the flu shot to become effective, so if the flu shot has just come to your neighborhood and will be around for a month or so, it still makes sense to get a flu shot," Edelman said.

Still, it's best to be prepared. "Immunization lasts about six months," Edelman said, "so earlier is always better, because you'll be protected, and you won't have to rush off when the flu hits your area." The flu season typically begins in the fall and peaks in February but can continue well though March.

Another myth: You can get sick from the flu shot. "A lot of people will get the flu shot and then maybe catch a cold, so they blame the flu shot for it, but they are not related," Edelman said. The shot itself is a standard injection in the arm, typically with little or no lingering soreness, he said.

Cain, who was set to get his own jab Monday morning at the event, agreed. "It doesn't really hurt," he said.

Getting immunized is not a guarantee that you won't get the flu, however, because each year scientists formulate the vaccine based on a highly educated guess of what influenza strains will dominate.

"The flu shot is probably about 85 to 90 percent effective in younger people, and in older people -- because their immune systems don't respond as well to the vaccine -- it may be closer to 65 percent effective," Edelman said. Still, "it's advisable to always get the flu shot, because there will always be at least partial immunity," he said.

On the other hand, the price of not getting vaccinated can be steep, especially for the very young or elderly. According to the lung association, 36,000 Americans die every year from influenza and about 226,000 are hospitalized. When combined with pneumonia, flu remains the eighth leading cause of death in the United States.

Unlike the 2004-2005 season, when production troubles caused a shortfall in available vaccine, there should be plenty of doses to go around this year, said Dr. Anne Schuchat, director of the U.S. Centers for Disease Control and Prevention's National Center for Immunization and Respiratory Diseases.

"This year, we have already distributed 103 million doses of vaccine, and that's more than we distributed the entire season last year," she said. "By the end of December, it could be up to 132 million doses, which is more than 10 million more than we have ever produced. So, we're pretty optimistic."

Garner believes she and other moms are key to helping flu-vaccination efforts reach their targets.

"I understand the important role mothers play in our families' health and well-being -- it is our natural instinct to take care of our families and keep them protected," she said. "This includes talking to our doctors about whether influenza vaccination is right for ourselves and our loved ones."

SOURCES: Nov. 12, 2007, press conference, American Lung Association, New York City, with Jennifer Garner, actress; Dean Cain, actor; Norman Edelman, M.D., chief medical officer, American Lung Association; Anne Schuchat, M.D., director, National Center for Immunization and Respiratory Diseases, U.S. Centers for Disease Control and Prevention, Atlanta