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Questions you may have about vaccines

February 06, 2012


Over the last few weeks, we’ve had a few . Here are some answers to common questions that parents may have about vaccines.

Should I be concerned about thimerosal, a mercury-containing preservative?

Preservatives have been used in some vaccines in the past to prevent contamination with bacteria and other harmful substances. Contamination with such substances could cause serious and even fatal bacterial infections, and thimerosal was used to prevent these harmful events.

However, due to concern by Congress and the news media, thimerosal has been removed from all childhood vaccines, with the exception of the influenza vaccine. The intense, public scrutiny has prompted some parents to worry that their child may have been harmed by thimerosal in their vaccines.

The amount of mercury in the influenza vaccine is extremely low, much lower even than our environmental exposure through soil, water and food. It has not been shown to be harmful at these miniscule levels.

A multitude of scientific studies shows that thimerosal does not cause autism.

Do vaccines cause autism?

Multiple studies have conclusively shown that neither vaccines nor thimerosal contained in vaccines cause autism.

Do vaccines overwhelm the immune system, especially giving so many at one time?

The immune system is extremely complex and very adept at fighting different viruses and bacteria. Vaccines only utilize a tiny fraction of the immune system, and giving multiple vaccines at one time will not “max out” a child’s immune system, even in infancy.

Although the number of vaccines we give to children has increased in recent decades, the actual number of components within the vaccine that affects the immune system has decreased. Vaccines today are much more targeted to contain only the specific parts needed for the desired immune response. We are protecting against more diseases, but this does not pose a threat of overwhelming the immune system.

Should I delay some of my child’s vaccines or use an alternative schedule?

The childhood immunization schedule is recommended by the Center for Disease Control and Prevention based on recommendations by a group of medical and public health experts. It is also approved by the American Academy of Pediatrics as well as the American Academy of Family Physicians.

These recommendations are made based on several considerations:

  • the safety and effectiveness of the vaccine when given at different ages
  • the severity of the disease and potential harm if children get the disease
  • the number of children likely to become ill if the vaccine were not give
  • the differences between how well the vaccine works for children at different ages
Rigorous testing has given experts information about when the child most needs protection from the most serious illnesses, and when vaccines will be the most effective in preventing those diseases.

There is no evidence that giving too many vaccines at one time is harmful in any way. However, delaying certain vaccines leaves a child vulnerable to developing a serious illness that could have been prevented with a vaccine.

Have you found this information helpful? Share with us other questions you’d like to discuss!