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Why does my child need a vaccine for a disease that doesn’t seem that serious?

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Common Questions-young girl plays in playground

Some diseases that vaccines can prevent may not seem that dangerous. And since most parents in the United States keep their kids up to date on routine vaccines, serious cases of vaccine-preventable diseases are much rarer than they used to be.source: 1,source: 2

  • Diseases that are thought of as mild can cause some children to get very sick or die. For example, most children will have mild or moderate cases of chickenpox or the flu. But chickenpox can cause pneumonia, encephalitis (brain swelling), and even death.source: 3,source: 4
  • There is no way to know who will develop a severe case of disease. Even healthy children can develop a life-threatening case of a disease that could have been prevented with a vaccine.source: 5
  • Diseases that are thought of as mild can cause children to miss school and parents to take time out of work to care for their children. For example, if your child gets chickenpox, then they will need to stay home from school and stay away from other children for 5 to 7 days,source: 4,source: 6 even if they have a mild case.
  • Vaccinating your child on time is the best way to protect them. Vaccination helps protect your child against a disease without your child having to get sick first. It can prevent cases that are mild, but especially those that are serious enough to cause hospitalization or death.source: 7 And it can help keep your child in school and doing what makes them happy.

Key Evidence

  • Children who are not up to date on their vaccines can get very sick or die from diseases like the flu and chickenpox.source: 8,source: 9
    • From 2010 through 2023, between 6,000 and 25,000 children under age 5 years in the United States got sick enough from the flu each year that they needed hospital care.source: 10 The seriousness of the flu changes from year to year. From the 2004–2005 season to the 2019–2020 season, flu-related deaths in children reported to the Centers for Disease Control and Prevention (CDC) during regular flu seasons have ranged from 37 to 199 deaths. Among reported flu-related deaths in children, about 80% occurred in children who were not fully vaccinated.source: 11
    • Chickenpox can also have serious complications. Before vaccines, over 10,000 people used to be hospitalized for it each year. Even now that most children are vaccinated, chickenpox is still dangerous for people who have not been vaccinated. Up to 1,400 people are hospitalized each year.source: 8
  • Diseases can cause lifelong disability and long-term complications.
    • Children with measles are at risk for a rare but deadly disease that affects their brain and spinal cord. It can appear up to 10 years after they seem to have recovered from measles. Measles can also leave children deaf or with intellectual disabilities.source: 12
    • HPV, a common but vaccine-preventable disease, can cause cancer.source: 13
  • Unvaccinated children are more likely than vaccinated children to spread diseases to family members who are at increased risk for severe illness or unable to get vaccinated.source: 14 Chickenpox and measles are so contagious that 1 infected person will spread these diseases to as many as 9 out of 10 people around them if those people are not immune.source: 15,source: 16 Chickenpox can be deadly for newborns, who are too young to get the vaccine. So when you vaccinate your child on time, you may be helping to protect a younger sibling or cousin, too.source: 17 Plus, many unvaccinated adults who died from chickenpox got it from their unvaccinated children.source: 4
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Common Questions-kids play basketball

A Deeper Dive: “Mild” Diseases Can Be Severe Years Later

Some diseases may be mild in childhood and cause more serious health issues later in life. Such health issues can happen months, years, or decades later.

  • Post-polio syndrome can affect polio survivors decades after their first infection. Some people may develop muscle weakness, tiredness, and joint pain.source: 18 This can make it difficult to function independently.
  • Being infected with rubella when pregnant can result in birth defects. This can include heart defects, deafness, liver and spleen damage, and intellectual and developmental disabilities.source: 19
  • Children with hepatitis B may not have any symptoms at first. It can take 3 months for hepatitis B symptoms to start after infection. Up to 90% of infants with hepatitis B develop a lifelong infection that can cause liver damage or cancer later in life.source: 20 When your child follows the vaccine schedule, you help protect them from the day they are born.
  • If your child gets chickenpox, they could have a mild case. But once they have had the disease, the virus remains “asleep” in their body. It can awaken years later in the form of a painful disease called shingles. Severe cases of shingles can cause pneumonia, hearing problems, swelling of the brain, and even death.source: 21 Children who are up to date with their chickenpox vaccines are less likely to get shingles later on.source: 22

When you vaccinate your child on time, you give them safe and effective protection against diseases.

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More information

Still have questions? Talk to your child’s doctor, nurse, or pharmacist.

Sources

  1. CDC: Vaccination Coverage With Selected Vaccines and Exemption Rates Among Children in Kindergarten—United States, 2021–22 School Year
  2. CDC: About the Vaccines for Children (VFC) Program
  3. CDC: Signs and Symptoms of Flu
  4. CDC: Chickenpox Symptoms and Complications
  5. CDC: Pediatric Flu Deaths Top 100 this Season; Most Unvaccinated
  6. American Academy of Pediatrics: Varicella (Chickenpox)
  7. CDC: Reasons to Vaccinate
  8. CDC: Chickenpox Vaccine Saves Lives Infographic
  9. CDC: Flu and Children
  10. CDC: Caregivers of Infants and Young Children
  11. CDC: More Than 100 Flu-Related Deaths in Children Reported So Far This Season
  12. CDC: Measles Symptoms and Complications
  13. HHS: HPV (Human Papillomavirus)
  14. CDC: About Vaccines for your Children
  15. CDC: About Chickenpox
  16. CDC: How Measles Spreads
  17. HHS: Infants and Children Birth Through Age 6
  18. CDC: About Polio in the United States
  19. CDC: Pregnancy and Rubella
  20. CDC: Hepatitis B Basics
  21. CDC: Shingles Symptoms and Complications
  22. CDC: Chickenpox VIS
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