The Claim in Context
Misleading claims that the cumulative number of vaccines on the childhood immunization schedule can overwhelm a child's immune system or cause other issues are inaccurate and dangerous. Individuals making this claim often say children receive 80 or more vaccines throughout childhood, which is not true and sows fear among parents. The pacing and combination of vaccines is based on the times when vaccines will work best with children’s immune systems and when they are most vulnerable to the diseases that vaccines protect them from. Sometimes this means children will receive multiple shots in a short period of time. Following the recommended childhood immunization schedule helps babies, children and teens stay healthy by teaching their immune systems to identify and resist serious, preventable diseases.
Key Facts
- Extensive testing is required for every vaccine, and research shows that getting multiple vaccines at the same time is safe. There is no medical reason to delay or space out childhood immunizations.
- The current recommended childhood and adolescent immunization schedule helps protect children against approximately 20 different infections. Most of these infections used to be common and are now rarely seen. Combination vaccines, like MMR or DTaP, combine multiple vaccines into a single shot. Most vaccines require multiple shots (doses) over the course of months or years to ensure a strong immune response.
- Extensive research and testing to identify the ideal dose level, number of doses, and timing of doses is required for every vaccine.
- All vaccines contain antigens, which are small molecules that trigger an immune response in the body. These substances are found on bacteria and viruses and help teach the body to create an immune response to protect against infections and diseases.
- Babies and young children are exposed to about 2,000 to 6,000 immune-triggering substances, also called antigens, every day. The current entire pediatric immunization schedule exposes a child to about 165 antigens.
- Children’s bodies can handle multiple vaccines at once because their immune systems are in constant learning mode. Multiple vaccines in one shot don’t overwhelm a child’s immune system—they give it helpful practice.
- In childhood, the immune system develops by learning to “read” germs like books. Vaccines are like beginner books that help the immune system get ready to read.
- Most children following the recommended schedule will receive about 30 shots protecting against about 20 diseases by the time they turn 18, excluding annual vaccines like the flu shot.
Evidence Snapshot
The American Academy of Pediatrics (AAP) has made pediatric vaccine recommendations since the 1930s. The first unified childhood vaccine schedule was created in 1995 by the AAP and the Centers for Disease Control and Prevention after decades of collaboration between leading medical organizations and the federal government. As medicine has evolved and scientists have learned more about diseases, the recommended childhood immunization schedule has also evolved to reflect the latest research.
Before new vaccines are added to the schedule, they are studied rigorously and are tested against placebos or existing vaccines. Currently, this schedule protects children from more than 20 dangerous diseases. Several studies have found that getting multiple combination vaccines do not overwhelm a child’s immune system. Babies encounter countless antigens like germs, bacteria, and viruses that stimulate their immune system’s development, so the number of antigens in vaccines is miniscule by comparison.
Why It Matters
Millions of children, families, and communities have benefited from vaccines for decades. Immunizations have been scientifically designed to teach children’s immune systems to recognize and resist serious diseases and are rigorously tested and monitored over time. Studies estimate that from 1994 to 2023, routine childhood vaccinations have prevented approximately 508 million cases of illness, 32 million hospitalizations, and over 1 million deaths. Because routine childhood immunizations are widely available and used in the U.S., most kids today will never get whooping cough, tetanus, polio or meningitis. When vaccination is widespread, contagious diseases have a hard time spreading, protecting all of us.
Experts Say:
“Just like children are always learning and growing, their immune systems are in constant learning mode and adapting to keep their bodies healthy and strong. Pediatricians recommend children receive certain vaccinations at specific times to help ensure their immune systems are ready to protect them from diseases as early and fully as possible—and sometimes this means getting several vaccines during a visit to the pediatrician’s office. Pediatric researchers and scientists have studied vaccines for decades to make sure that they are safe and that receiving multiple vaccines at one time doesn’t overwhelm a child’s immune system. The recommended childhood immunization schedule is designed to help ensure children’s immune systems are up to date and prepared to protect them from serious, preventable diseases when they need it most."
— José Romero, MD, FAAP, Member, AAP Committee on Infectious Diseases
Resources for Further Information
Last Updated
10/10/2025
Source
American Academy of Pediatrics