Are Childhood Vaccines Safe?

Medically Reviewed by Roy Benaroch, MD on April 13, 2015

Childhood vaccinations protect kids from dozens of diseases, some of which can be deadly. But how do you know that the vaccines themselves are safe?

Scientists do a lot of work on these medicines before they ever get to a doctor’s office or pharmacy. In most cases, vaccines are some of the safest and best ways to keep kids healthy. And they’re definitely less dangerous than the diseases they aim to prevent.

Researchers have to show firm evidence that a vaccine works and is safe for people in order to get it approved by the FDA. The research to prove that can take a decade or longer.

Once a vaccine gets approved, health officials use nationwide monitoring systems to watch for any reports of new or dangerous side effects. Any hint of a problem means officials will take action. They might change the vaccine’s label, send out safety alerts, or revoke a vaccine’s license.

No. Some vaccines have aluminum and formaldehyde, but people, including babies, are used to these substances. In fact, babies can get more aluminum from breast milk than from vaccines.

Like all medicines, vaccines can cause some side effects, like soreness, redness, and sometimes a little swelling at the spot where your child gets a shot. Some kids can have mild fevers, too. The problems usually go away after a day or two.

Serious side effects, like a severe allergic reaction, seizures, hearing loss, or severe pain, are very rare -- so rare that experts aren't even sure they're linked to vaccines.

After your child gets vaccinated, watch for any signs she’s having a bad reaction, like trouble breathing, hives, or feeling weak or dizzy. Let her doctor know right away if you notice any changes in her.

Kids come into contact with hundreds if not thousands of bacteria and viruses every day. The entire vaccine schedule exposes them to only 150 germs. Studies show that getting several shots at one time won’t harm them.

In fact, it might be better to get them done in fewer doctor’s visits. It’s less stressful that way. Plus, the sooner your child is vaccinated, the sooner she’ll be protected.

Vaccines are generally safe, but some children should wait to get them. And some shouldn’t get them at all. Check with your doctor if your child:

  • Has ever had a severe reaction to a vaccine or to any of its ingredients.
  • Is very ill. If she has a cold or the sniffles, it’s usually OK to vaccinate her.
  • Has a weak immune system either because of a disease (like cancer or HIV/AIDS) or due to medications, such as steroids, radiation therapy, or chemotherapy.

Always make sure your child’s doctor knows about her allergies and health conditions when you talk about vaccines. The doctor is the best source of information on which vaccines your child needs and can get safely.

Show Sources


Frank DeStefano, MD, MPH, director, immunization safety office, CDC.

CDC: "Frequently Asked Questions about Multiple Vaccinations and the Immune System," "Facts for Parents: Diseases & the Vaccines that Prevent Them," "Diseases & the Vaccines that Prevent Them: Measles," "Understanding How Vaccines Work," "Possible Side-effects from Vaccines," "Frequently Asked Questions About Vaccine Safety."

California Immunization Coalition: "Vaccine Safety Facts for Parents."

American Academy of Pediatrics: "Vaccine Safety," "The Childhood Immunization Schedule: Why Is It Like That?"

Hepatitis B Foundation: "Statistics."

The Children's Hospital of Philadelphia: "General Vaccine Safety Concerns," "Can Children Manage So Many Different Vaccines at the Same Time?"

Institute of Medicine: "Childhood Immunization Schedule and Safety: Stakeholder Concerns, Scientific Evidence, and Future Studies."

© 2010 WebMD, LLC. All rights reserved. View privacy policy and trust info