MYTH: Vaccines can cause the infections they are meant to protect against.

FACT: Vaccines contain either highly weakened or very small parts of an organism which cannot cause infection. Vaccines can cause mild side effects that usually go away in a day or two. These include local reactions like minor redness or swelling where a vaccine is injected, or sometimes a low grade fever. The measles, mumps, rubella (MMR) and chicken pox (varicella) vaccines can rarely cause fever and a rash within a few weeks of vaccination.

Visit here to learn more about the potential side effects of different vaccines.

MYTH: Vaccines contain dangerous ingredients.

FACT: While vaccines contain very small amounts of some additional ingredients as part of the production process, to prevent contamination, or to improve their effectiveness, they pose no health hazards. Unfortunately, there are many myths and misunderstandings about these ingredients.

Visit here to learn more about these vaccine ingredients and why they are considered to be safe.

MYTH: Vaccines cause autism.

FACT: Vaccines do not cause autism. This myth began when a doctor from England published a paper that was later found to be a fraud. The paper was retracted by the journal that published it and the doctor lost his license to practice medicine, but the myth has persisted to this day. Many studies since then have shown that there is no link between vaccines and autism.

Visit here to learn more about where this myth came from, and how we know vaccines do not cause autism.

MYTH: So many vaccines given at once can overwhelm an infant’s immune system.

FACT: Vaccines are no threat to a child’s immune system. Vaccines contain small amounts of tiny pieces of a virus or bacteria, or a small number of weakened organisms that cannot cause infection. On the other hand, infants constantly face threats from large numbers of actual organisms trying to cause infection and disease. So, although it may seem that giving multiple vaccines at the same time is too much for a child, their immune system can handle them easily and still be able to fight off the many real threats it faces.

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MYTH: The United States childhood immunization schedule contains too many vaccines.

FACT: The current US childhood immunization schedule was developed by leading public health and infectious disease scientists after extensive debate and examination of the best available evidence, and in the context of our country’s specific population and public health dynamics. There is no evidence that the schedule contains too many vaccines. To the contrary, the best available evidence strongly supports the current schedule. According to the CDC’s own report in 2024, “Among children born [in the United States] during 1994–2023, routine childhood vaccinations will have prevented approximately 508 million lifetime cases of illness, 32 million hospitalizations, and 1,129,000 deaths, resulting in direct savings of $540 billion and societal savings of $2.7 trillion.”

Visit here to learn more about the US vaccine schedule, and visit here to learn why it should not be changed.