Making the Vaccine Decision: Addressing Common Concerns

Most parents choose to vaccinate their children according to the recommended schedule. But some parents may still have questions about vaccines.

Mother and baby son at a doctor appointment.

Vaccines protect against diseases

Different types of vaccines work in different ways to offer protection. With all types of vaccines, your body will remember how to fight that virus in the future. It typically takes a few weeks after vaccination for the body to build up that protection.

Strengthening your baby’s immune system

Immunity is the body’s way of preventing disease. Your baby’s immune system is not fully developed at birth which can put your baby at a greater risk for infection. Vaccines reduce your child’s risk of infection by working with the body’s natural defenses to help safely develop protection against disease.

Illustration of a baby with a teddy bear.

Children are exposed to thousands of germs every day. This happens through the food they eat, air they breathe, and things they put in their mouth.

Droplet.

Babies are born with immune systems that can fight most germs, but there are some serious and even deadly diseases they can’t handle. That’s why they need vaccines to strengthen their immune system.

Antigens.

Vaccines use very small amounts of antigens to help your child’s immune system recognize and learn to fight serious diseases. Antigens are parts of germs that cause the body’s immune system to go to work.

Learn more about how vaccines work with the body’s immune system and different types of immunity.

Vaccine ingredients

Today’s vaccines use only the ingredients they need to be as safe and effective as possible. All ingredients of vaccines play necessary roles either in making the vaccine, triggering the body to develop immunity, or in ensuring that the final product is safe and effective. Some of these include:

  • Adjuvants help boost the body’s response to a vaccination. (Also found in antacids, buffered aspirin, antiperspirants, etc.)
  • Stabilizers help keep a vaccine effective after it is manufactured. (Also found in foods such as Jell-O® and resides in the body naturally)
  • Formaldehyde is used to prevent contamination by bacteria during the vaccine manufacturing process. It resides in body naturally (more in body than vaccines). (Also found in environment, preservatives, and household products.)
  • Thimerosal is also used during the manufacturing process but is no longer an ingredient in any vaccine except multi-dose vials of the flu vaccine. Single dose vials of the flu vaccine are available as an alternative. No reputable scientific studies have found an association between thimerosal in vaccines and autism.
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Some websites may claim that ingredients are harmful, make sure you seek information from credible sources.

Vaccines are safe

Before a new vaccine is ever given to people, extensive lab testing is done. Once testing in people begins, it can sometimes take years before clinical studies are complete and the vaccine is licensed.

Once a vaccine is licensed, the Food and Drug Administration (FDA), CDC, National Institutes of Health (NIH), and other federal agencies routinely monitor its use and investigate any potential safety concerns.

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CDC and the FDA take many steps to make sure vaccines are very safe both before and after the public begins using the vaccine. Making sure vaccines are safe is a priority for CDC.

Mild side effects are expected

Vaccines, like medicine, can have some side effects. But most people who get vaccinated have mild or no side effects. The most common side effects may include fever, tiredness, body aches, and redness, swelling, and tenderness at the site where the shot was given. Mild reactions usually go away on their own within a few days. Serious, long lasting side effects are extremely rare.

If you have questions or concerns about a vaccine, talk with your child’s doctor. Learn about the safety of each recommended vaccine.

Why your child should get vaccinated

Vaccines can prevent serious diseases that once killed or harmed many infants, children, and adults. Without vaccines, your child is at risk for serious illness or even death from diseases like measles and whooping cough.

Combination vaccines.
MEASLES: The United States had more than 1,200 cases of measles in 2019. This was the greatest number of cases reported in the U.S. since 1992 and since measles was declared eliminated in 2000.

It is always better to prevent a disease than to treat it after it occurs.

  • Vaccination is a highly effective, safe, and easy way to help keep your family healthy.
  • The timing of vaccination is based on how your child’s immune system responds to vaccines at various ages and how likely your child may be exposed to disease.
  • Vaccines are tested to ensure they are safe and effective for children to receive at the recommended ages.

CDC vaccine information statements (VISs) explain both the benefits and risks of a vaccine. VISs are available for each vaccine.

Page last reviewed: July 5, 2022