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This Q&A describes the importance of childhood immunizations and lists resources for readers who want to explore the topic further.

Why should my child be immunized?

Babies will acquire antibodies to some diseases from their mother’s body before birth and from breastmilk as long as they are breastfed. However, they are still vulnerable to many infections, and the immunity they receive from their mother disappears quickly.

Some illnesses may seem like a normal part of childhood. Grandparents may remember having mumps, measles, or chickenpox. Many of us have had a flu. However, some children who suffer these illnesses die or develop lifelong complications, such as the type of deafness or infertility that can be caused by mumps. Of every 1,000 children who get measles, one to three will die from the disease. 

Vaccines prevent many such diseases that once harmed and killed children. For example, Haemophilus influenzae type b (Hib) infection can cause the epiglottis in the throat to swell, cutting off a child’s ability to breathe. After the Hib vaccine was introduced in the mid-1980s, the incidence of Hib dropped by 99%. In addition, research suggests that the risk of SIDS is reduced by 50% in immunized infants.

Although the chances of a child coming into contact with many diseases has decreased because of vaccinations, viruses and bacteria still exist and can be carried quickly in our mobile society. Every year in the United States, there are outbreaks of some diseases; these diseases can spread easily among children or adults who have not been immunized.

In addition to protecting the individual child, high vaccination rates protect communities by slowing or stopping the spread of disease. Stopping the spread of disease helps protect those who cannot be vaccinated because they are too young, too old, or too sick. A high vaccination rate in the community also helps prevent congenital disorders, also known as birth defects, that may be caused when a pregnant woman is infected.

How do immunizations prevent illness?

From birth, a healthy child’s immune system fights invading antigens, which stimulate the immune system to produce antibodies. A healthy immune system produces thousands of specific antibodies every day to fight specific antigens. Some antibody cells become “memory cells” that develop immunity to returning bacteria or viruses. If the body has no memory cells, some bacteria or viruses can cause severe illness before the immune system can produce antibodies to fight it.

Vaccines protect children by helping their bodies make antibodies against specific diseases. Vaccines are made using the killed or weakened antigens, or parts of them, that cause disease. Vaccine antigens are designed to alert the immune system to produce antibodies against a disease without causing the disease. The antibody memory cells remain to react quickly if they encounter the disease in the future. Vaccination leads to immunity without the child having to suffer from the actual disease. Read more about how vaccines work from the CDC.

Can vaccines harm my child?

Vaccines are much safer than the diseases they prevent. They are widely tested. A vaccine is monitored for safety as long as it is being used.  Each new vaccine goes through several phases of testing, including clinical testing in volunteers, before it is approved by the Federal Drug Administration (FDA). The third phase involves testing in at least 10,000 people, and this stage lasts up to four years. The vaccine must be proven to be both safe and effective before it can be licensed for general use.

Immunizations, like any medication, can have side effects. A health care provider should be familiar with a child’s medical history before giving an immunization. For most children, the side effects may include a mild fever and soreness at the vaccination site. A very few children out of the millions vaccinated will have more serious problems, such as seizures or severe allergic reactions.

Extensive research studies have found no relationship between vaccines and autism spectrum disorders (ASDs). Not immunizing your child leaves them unprotected against diseases that can be dangerous or deadly. It also puts others at risk. Meanwhile, research continually improves the safety of immunizations.

Is it harmful for my baby to get so many vaccines so quickly?

Babies encounter many germs from breathing, eating, and interacting with people. A healthy infant’s immune system helps keep them well by reacting to thousands of antigens every day. Thanks to advances in science, today’s vaccines can protect children from more diseases using fewer antigens. In fact, just 305 antigens are used to protect children against 14 diseases by age 2. 

Doctors and disease experts design a standard immunization schedule based on recent research. The American Academy of Pediatrics, the Centers for Disease Control and Prevention, and the American Academy of Family Physicians approve the schedule. It is important to work with your child’s health care provider to determine whether the standard immunization schedule is appropriate for your child. 

What immunizations do my children need?

The CDC recommends that children be immunized against diphtheria, pertussis, tetanus, polio, measles, mumps, rubella, flu, Haemophilus influenzae type b (Hib), hepatitis A and B, chickenpox, pneumococcal diseases, and rotavirus.

In Illinois, parents of children 2 months old and older who are entering a childcare facility need to show proof that the children have been or are in the course of being immunized, as suggested in the state’s immunization schedule, against diphtheria, pertussis, tetanus, polio, measles, mumps, rubella, Haemophilus influenzae type b (Hib), hepatitis B, and varicella (chickenpox). (See Illinois Department of Public Health Back to School Immunization Requirements.)

In Illinois, parents of children entering childcare or public school programs (including preschool programs, early childhood programs, Head Start, or other prekindergarten programs), need to show proof that their children have been immunized against diphtheria, pertussis, tetanus, polio, measles, mumps, rubella, Haemophilus influenzae type b (Hib), hepatitis B, and varicella (chickenpox). Parents should check with their child’s health care provider and preschool program.

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About this resource

Setting(s) for which the article is intended:
  • Home
  • Family Child Care
  • Child Care Center
  • Preschool Program

Intended audience(s):
  • Parents / Family
  • Teachers / Service providers

Age Levels (the age of the children to whom the article applies):
Reviewed: 2022