"With the flu, it's a moving target," she said. The viral genes shift, and annual flu vaccines provide only partial and temporary immunity. Immunity across the population is harder to establish without more widespread vaccination. "A 20- to 30-percent vaccination rate doesn't cut it."
Public health officials say they're also fighting a common and persistent myth about flu vaccines - the often repeated complaint that "I got the shot and it made me sick," or "I got the flu anyway."
The first complaint is "clearly a fallacy," Bailowitz said. "The shot in the arm is killed virus. There are no live 'bugs.' ... That is an unfortunate myth we have every year to combat."
The second myth is likely perpetuated by the fact that the flu vaccine does not protect against other respiratory diseases that circulate in the winter, and that the vaccine is not 100 percent effective, said Dr. Robert Edelman, associate director of clinical research at the Center for Vaccine Development at the University of Maryland School of Medicine.
Critical to protecting the most vulnerable populations from the seasonal flu, Edelman said, is immunizing as many young children as possible.
"The kids bring it home first," Edelman said. Their immune systems are "naive," so they more easily catch the flu, and they get sicker. "They have a lot of virus. They're sneezing, they cough in their hands and then they come and kiss Grandpa ... or share a cup of root beer with Grandma."
The elderly tend to be partially immune, thanks to their long years of exposure to similar flu strains, and they put out less virus than kids.
"Nevertheless, they can get quite sick from it," Edelman said, especially those with chronic heart or lung conditions, cancer, or those taking drugs to suppress the immune system, including steroids used to control asthma.
To find a flu immunization clinic near you, visit www.findaflushot.com
