Childhood Vaccines
Childhood vaccines provide immunity to kids before they are likely to be exposed to harmful diseases. Vaccine programs throughout the lifespan reduce the transmission of viruses and bacteria that increase the risk of disability and death. Below are answers to some commonly asked questions:
Is immunity from natural infection better than vaccination?
No. Acquiring immunity through natural infection carries significant risks that vaccination helps prevent. For example: Polio can cause paralysis, Pneumococcal disease can lead to meningitis, and Measles can cause brain inflammation, blindness and death.
Do vaccines contain mercury and other harmful chemicals?
Thimerosal, a mercury containing compound, was previously used in multidose vials of the influenza vaccine. Although no evidence demonstrated harm, thimerosal was removed from all vaccines as of 2025. Formaldehyde is used in some vaccines as an inactivating agent. The amount present is far lower than what is commonly found in everyday products such as cosmetics, antihistamines, mouth wash and cough drops. Similarly, scant amounts of aluminum are present in some vaccines to enhance immune response. These amounts are lower than what people are routinely exposed to through food, water and medications.
Are food allergies a contraindication to vaccinations?
Food allergies are not a contraindication for routine childhood vaccinations. The MMR and Varicella vaccine contain negligible amounts of egg protein, and do not pose a risk for egg-allergic patients. Additionally, the influenza vaccine (flu shot) does not require any special precautions for egg-allergic patients.
Patients with a known gelatin allergy should discuss gelatin-free vaccine alternatives with their healthcare provider. In cases of documented gelatin allergy, skin testing and a graded challenge may be considered. Milk allergy is not a contraindication for routine vaccines.
Special consideration should be given to egg-allergic patients for the Yellow Fever vaccine and the rabies vaccine (except Imovax). Patients with a history of allergic reaction or anaphylaxis to egg should undergo evaluation prior to receiving the Yellow Fever vaccine. The Imovax Rabies Vaccine can be given without consultation with an allergist as this does not contain egg.
What if I think I had a vaccine reaction?
The risks of vaccination must always be considered against the risk of remaining susceptible to vaccine-preventable diseases. Serious reactions are exceedingly rare, occurring in approximately 1 in 1 million doses. Many patients who experience suspected reactions can safely receive future doses. Evaluation by an allergist, including skin testing, and when appropriate, a graded vaccine challenge, can help determine whether a true allergy exists.
For Additional Information:
Vaccines: The Myths and the Facts | AAAAI