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, and getting answers they can trust may be hard.

Doctor reviews a patient's medical information.

Talk to your child's doctor if you have questions or concerns about vaccines for your child.

With so much information—and sometimes incorrect information—available today, learning the facts before making health decisions is very important.

How vaccines work: preventing diseases

The diseases vaccines prevent can be dangerous, or even deadly.

Statistically, the chances of your child getting diseases such as measles, pertussis, or another vaccine-preventable disease might be low, and your child might never need the protection vaccines offer. HOWEVER, you don’t want them to be lacking the protection vaccines provide if they ever do need it.

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Think of it this way: You always make sure to buckle your child in his car seat even though you don’t expect to be in an accident.

Strengthening your baby’s immune system

Immunity is the body’s way of preventing disease. When your baby is born, his/her immune system is not fully developed, which can put him/her at greater risk for infections. Vaccines reduce your child’s risk of infection by working with his/her body’s natural defenses to help safely develop immunity to disease.

Baby flexing his muscles.

Your child is exposed to thousands of germs every day in his environment. This happens through the food he eats, air he breathes, and things he puts in his mouth.


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


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.

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Think of it this way: Getting a disease or getting a vaccine can both give you future protection from that disease. The difference is that with the disease you have to get sick to get that protection. With the vaccine you don’t.

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

Vaccine ingredients

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 vaccine. (Also found in antacids, buffered aspirin, antiperspirants, etc.)
  • Stabilizers help keep vaccine effective after manufactured (Also found in foods such as Jell-O® and resides in the body naturally.)
  • Formaldehyde is used prevent contamination by bacteria during the vaccine manufacturing process. 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, but you have to make sure as you surf for vaccine information to seek information from credible sources.

Vaccines are safe

The safety of vaccines is often a topic of media stories and blog postings. This attention may make you wonder, “How do I know vaccines are safe?”

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

Before a vaccine is ever given to people, FDA oversees extensive lab testing of the vaccine that can take several years to make sure it is safe and effective. After the lab, testing in people begins, and it can take several more years before the clinical studies are complete and the vaccine is licensed.

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

The Journey of Your Child's Vaccine.

Watch this 6 minute video to see how a vaccine is developed, approved, manufactured; added to the schedule, and how the vaccine’s safety continues to be monitored.

Mild side effects are expected

Like any medicine, vaccines can cause side effects such as a low-grade fever, or pain and redness at injection site. Mild reactions go away within a few days on their own.

Severe, 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.

Combination and multiple vaccines are safe

Combination vaccines.
Receiving combination vaccines and/or multiple vaccines at same time is safe and offers protection against multiple diseases during one office visit.

Giving several shots at the same time means fewer office visits. This saves you time and money, and can be less traumatic for the child.

A decision not to immunize your child also involves risk and could put your child and others who come into contact with him or her at risk of contracting a potentially deadly disease.

The best protection from 14 serious diseases.

Why your child should get vaccinated

Vaccines can prevent infectious diseases that once killed or harmed many infants, children, and adults. Without vaccines, your child is at risk for getting seriously ill and suffering pain, disability, and 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.
  • On-time vaccination throughout childhood is essential because it helps provide immunity before children are exposed to potentially life-threatening diseases.
  • Vaccines are tested to ensure that 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.

If you don’t follow CDC’s recommended schedule

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Children do not receive any known benefits from following schedules that spread out or delay vaccines.

If you delay, reject, or skip doses of vaccines

Illustration of mother securing baby into car seat.

For parents who have questions about the schedule or wonder why it’s so important to follow, here are six reasons why you should vaccinate your child on time.

It can take weeks for a vaccine to help your baby make protective disease-fighting antibodies, and some vaccines require multiple doses to provide best protection. If you wait until you think your child could be exposed to a serious illness – like when he starts daycare, travels abroad, or during a disease outbreak – there may not be enough time for the vaccine to work.

If you wait to vaccinate

Young children can be exposed to vaccine preventable diseases, from any number of people or places, including

  • parents
  • brothers or sisters
  • visitors to their home
  • people returning from traveling abroad
  • on playgrounds, or even
  • at the grocery store

If you don’t vaccinate, know your responsibilities

Your child can catch diseases from people who don’t have any symptoms.  You can’t always tell who is contagious.

It’s your responsibility

  • To inform your child’s school, childcare facility, and other caregivers about your child’s vaccination status.
  • Notify the doctor’s office, urgent care facility, ambulance personnel, or emergency room staff that your child has not been fully vaccinated. They need to consider the possibility that your child may have a vaccine-preventable disease so that they can treat your child correctly as quickly as possible.
  • Isolate your child so disease during an outbreak does not spread to your child and others especially infants too young to be fully vaccinated.
  • Look up the countries where you will travel on the CDC travelers’ website before traveling. Travelers are exposed to diseases during travel or by others that traveled and returned to the U.S.
Page last reviewed: August 5, 2019