The posting on an Internet Web site sounded plaintive. Marianna Toce Gerstein wondered whether as a pregnant woman she should get a flu shot.
Although influenza vaccines are recommended for pregnant women, she was worried because she knows the vaccine contains a mercury-based preservative called thimerosal. She fears it could injure her unborn child.
“Has anyone else struggled with this?” she asked.
Gerstein’s gynecologist told her to get the vaccine but her other doctor, an internist, told her not to take the risk with her baby’s health. Gerstein is aware of the advice from the Centers for Disease Control and Prevention: Pregnant women in their second and third trimesters should get the shot because their immune systems are suppressed.
But she does not want to blindly follow anyone’s advice.
She is not alone. A survey published this month suggests a growing number of U.S. parents are beginning to question either the need for vaccines for their children, or the need to follow the recommended schedule of multiple shots between the ages of 3 months and 3 years.
“We found that a large number of both pediatricians and family physicians had experienced at least one parent vaccine refusal in the last year,” Dr. Gary Freed of the University of Michigan said in a telephone interview.
The survey of nearly 1,500 doctors found that 93 percent of pediatricians and 60 percent of family physicians had seen at least one parent who refused a vaccine for his or her child in the past year.
Worries about side effects
Writing in the January issue of the American Journal of Preventive Medicine, Freed and colleagues said 19 percent of doctors reported the parents feared the vaccines could affect their babies’ immune system.
Sixteen percent said the parents wondered whether children really needed all the vaccines recommended by the CDC.
“A growing number of parental concerns were relating to unproven or disproven concerns about childhood immunization such as whether mercury was harmful or the now disproven speculation about an association between the MMR (measles, mumps and rubella vaccine) and autism,” Freed said.
The CDC is clear: Vaccines save lives, are extremely safe and are still necessary.
For instance, measles makes as many as 40 million people around the world sick every year and kills 745,000, according to the World Health Organization.
“If vaccinations were stopped, each year about 2.7 million measles deaths worldwide could be expected,” the CDC says.
In Britain a growing anti-vaccine movement means just 84 percent of children are immunized against measles by age 2 -- a level that leaves the population vulnerable to an epidemic. Last year, 308 cases of measles were reported in Britain.
Gerstein appreciates the benefits of vaccines, but says no one can tell her the risk-benefit trade-off of getting herself vaccinated against flu. Adding to the confusion are recent Food and Drug Administration advisories that some tuna contains high levels of mercury and that pregnant women should limit how much they eat.
“You see signs around the doctor’s office all the time telling you not to eat (certain) fish,” she said in a telephone interview. “And at same time there is this whole thing with thimerosal and vaccines.”
Vaccine experts were confused, too -- so much so that the Environmental Protection Agency bases its limits for mercury exposure on what is known about damage done by methyl mercury contamination.
Methyl mercury is the form found in fish. But the mercury in thimerosal is ethyl mercury.
“These two molecules are very different,” said Dr. Paul Offitt, an immunization expert at Children’s Hospital of Philadelphia.
“They are just biologically very different agents. The problem is the word mercury is at end of both of them and there is no way that mercury ever sounds good.”
But Offitt and colleagues at the National Partnership for Immunization recently completed a review of mercury studies and concluded that the very small dose of mercury contained in thimerosal-preserved vaccines is cleared by the body before it can do any damage.
“The mercury ... from thimerosal -- it is eliminated from the body much more quickly than methyl mercury,” said Dr. Polly Sager of the NPI and a researcher at the National Institute for Allergy and Infectious Diseases.
In any case thimerosal has been removed from all childhood vaccines.
Gerstein was relieved to hear about the group’s findings but is still worried that she could not find any details about the risks and benefits of a pregnant woman getting a flu shot. She ended up not getting one, and plans to wash her hands frequently and avoid situations where she may get flu.