Less than half the parents in this country plan to give their kids the H1N1 flu vaccine according to a national poll by the University of Michigan.
With the vaccine being rushed to market and clinical trials still underway, Americans are worried about whether it's been fully checked out and whether it could have serious side effects.
Trials are still underway, and there are still a lot of unknowns, but experts say there are also a lot of myths out there that could hurt the people who need this vaccine the most.
The first doses of H1N1 vaccine won't be shipped for another week or so but the University of Michigan found only 40 percent of parents plan to give it to their children.
The concern, serious side effects.
"There's absolutely no way a vaccine could cause the process that results in a heart attack," said Dr. Janet Wright of the American College of Cardiologists.
Heart attack, stroke, seizures, sudden infant death syndrome, miscarriages or the flu itself.
The Centers for Disease Control says there's no evidence the vaccine can cause any of these problems.
But doctors fear misinformation may keep high risk patients away.
"It is so important for patients who know they have a heart problem to get the vaccine so that if they get the flu it'll be a milder case," Wright said.
In 1976, flu shots were pulled after thousands of people contracted the paralyzing Guillian Barre Syndrome.
"We have no reason right now to expect that. But we want to be ready if the unexpected occurs," said Dr. Jay Butler of the Centers for Disease Control.
The CDC is planning an aggressive monitoring program to compare, for instance, normal rates of stroke to those among people who get the vaccine.
"What's gonna be challenging is to figure out whether or not the vaccine caused that, and to do it as soon as possible," Butler said.
But experts emphasize, this is the exact same type of shot that's proven safe in years past with a new virus inserted.
And there's no evidence so far of any harmful side effects.
Researchers at Harvard and Johns Hopkins will be following up with people who get the vaccine and later become sick, to see if the two are related.