Vaccine Safety

Vaccine Safety

Many parents worry about the possible side effects of vaccinating their child and if their child really needs all those shots. Misinformation abounds on the Internet, making it hard to find a reliable source of information. Check below for expert answers on your top vaccine safety questions.


The AAP Immunization Web site was assessed by the World Health Organization (WHO) and passed their credibility and good information criteria. It is included in the WHO's list of vaccine safety websites. (Exit site)



Thimerosal, Aluminum, & Other Ingredients

Vaccines contain many ingredients that make them safer and more effective, including preservatives, adjuvants, and other ingredients. Click on the categories below to visit our Ingredients page and jump to information on that ingredient.



MMR and Autism

A few years ago, some parents believed that the measles, mumps, and rubella vaccine was causing children to develop autism, but studies since then have disproved that theory. For FAQs specific to MMR and/or autism and vaccines, visit this page.

Autism spectrum disorders (ASDs) are a group of related brain-based disorders that affect a child's behavior, social, and communication skills. Approximately 1 in 88 children are diagnosed with an ASD. Because the MMR vaccine is first given at age 12-15 months, and the first signs of autism often appear at 15-18 months of age, concerns have been raised about a possible link between the vaccine and the development of autism. Studies conducted in the US and Europe have found no association between the MMR vaccine and autism. Over the years, the Institute of Medicine and the AAP have organized several panels of independent scientists – all concluded no association between MMR and autism.

To learn more about how this concern began, read studies disproving the link between MMR and Autism, and for more resources, visit the MMR Vaccine page.


Why so Many Shots at Once?

Children can now be protected against 14 diseases by the time they are 2, but that also means they need many shots at one time. Some parents worry that too many vaccines given at one time will overwhelm their baby's immune system. But babies' bodies fight off germs every day- their immune systems are ready and waiting to keep them healthy! Vaccinations are a drop in the bucket compared to the amount of germs they fight off every day.

Infants and children are exposed to many germs every day just by playing, eating, and breathing. Their immune systems fight those germs, also called antigens, to keep the body healthy. The number of antigens that children fight every day (2,000-6,000) is much more than the number of antigens in any combination of vaccines on the current schedule (150 for the whole schedule). So children's immune systems are not overwhelmed by vaccines. Visit this page for FAQs on the immunization schedule.

The schedule is considered the ideal schedule for healthy children but there may be exceptions. For example, your child might not receive certain vaccines if she has allergies to an ingredient in the vaccine, or if she has a weakened immune system due to illness, a chronic condition, or another medical treatment. Sometimes a shot needs to be delayed for a short time, and sometimes not given at all. Your pediatrician stays updated about new exceptions to the immunization schedule. This is one reason your child's complete medical history is taken at the pediatrician's office, and why it is important for your child's health care providers to be familiar with your child's medical history.

Ask your pediatrician about the possibility of combination vaccines, which lessen the amount of needle sticks for your child but still provide protection against the same number of diseases.

For More information:

 To view this information on a separate page, please click here


How Vaccines are Licensed and Studied


Information from Other Trusted Sources


Amy's Story

Spotlight on HealthAmy Pisani shares how her son became dangerously ill with influenza as a toddler.



Last Updated: 10/30/2013

Contact Us | Privacy Statement | About Us | Home
American Academy of Pediatrics, 141 Northwest Point Blvd., Elk Grove Village, IL, 60007, 847-434-4000