En español

Some people wonder if vaccines cause other conditions. These concerns have arisen for a few reasons, such as: 

• We do not know the causes of all diseases.
• While rates of infectious diseases have decreased over time, rates of some chronic diseases have increased.

In this section, we address only a few of the conditions that have been discussed in relation to vaccine safety; however, we offer a much more extensive list with explanations and studies on the Vaccine Education Center website.

Allergies and asthma

Vaccines do not prevent most childhood infections. This means that vaccines are unlikely to alter the balance of cells that control allergic responses. Several large, well-controlled studies have shown that children who get vaccines are not at greater risk of having allergies or asthma.

• Get answers to common questions regarding vaccines and allergies. (PDF)
• Do vaccines cause allergies? (video)
• Are there vaccines children with allergies need to avoid? (video)

Autism

The MMR vaccine, thimerosal in vaccines, and receiving too many vaccines at one time have all been suggested as a cause of autism. However, numerous large, well-controlled scientific studies have shown that:

• Children who receive the MMR vaccine are not at increased risk of autism.
• The chance of getting autism is the same in children who received vaccines containing thimerosal and children who received vaccines without thimerosal.
• Too many vaccines do not cause autism.
• An alternative vaccination schedule does not reduce the risk of autism.

Resources for additional information

• Read more about vaccines and autism: English | Spanish | Japanese | Somalian (PDF)
• Read more about thimerosal in vaccines: English | Spanish (PDF)
• Read more about concerns related to too many vaccines: English | Spanish (PDF)
• Read more about the recommended immunization schedule: English | Spanish | Japanese (PDF)
• Do vaccines cause autism? (video)
• Tylenol During Pregnancy Does Not Cause Autism (video)

Chronic diseases

Some have wondered if vaccines cause chronic diseases. Chronic diseases are diseases that do not go away. Rather, people live with them for the rest of their lives. Examples include diabetes, multiple sclerosis and arthritis.

Studies looking at receipt of vaccines and development of chronic diseases have been completed. They have shown no link between getting vaccinated and developing chronic or other autoimmune diseases. Vaccines do not induce strong enough immune responses to cause chronic conditions.

• Read more about different chronic conditions and vaccines. (webpage)
• Do vaccines cause autoimmune or chronic disorders? (video)

Reviewed by Paul A. Offit, MD, on Feb. 2, 2026