CT Health Officials Reaffirm Vaccines Do Not Cause Autism

CONNECTICUT — Connecticut health officials on Thursday reaffirmed that childhood vaccines do not cause autism, citing decades of scientific research.

In a statement, the Connecticut Department of Public Health said extensive studies have repeatedly found no credible evidence that routine immunizations lead to autism spectrum disorder. The agency said vaccines undergo rigorous testing before approval and continue to be monitored for safety once in use.

“Real-world evidence show us that vaccines protect our children from unanticipated exposures to highly infectious, preventable pathogens that could lead to long-term disability and even death,” DPH Commissioner Manisha Juthani said. “Despite this recent political development fueling vaccine hesitancy, the scientific consensus remains clear and overwhelming.”

The department pointed to multiple large-scale studies, including a 2002 Danish analysis of more than 500,000 children, a 2006 Canadian study of more than 27,000 children, and a 2015 U.S. study involving more than 95,000 siblings of children diagnosed with autism. All found no increased risk of autism associated with the measles, mumps and rubella vaccine.

National medical organizations echoed Connecticut’s stance. Susan Kressly, president of the American Academy of Pediatrics, criticized recent changes to the Centers for Disease Control and Prevention’s website that she said amplify false claims about vaccine risks.

“Since 1998, independent researchers across seven countries have conducted more than 40 high-quality studies involving over 5.6 million people. The conclusion is clear and unambiguous: There’s no link between vaccines and autism,” Kressly said. “Anyone repeating this harmful myth is misinformed or intentionally trying to mislead parents.”

Alison Singer, president of the Autism Science Foundation, said continued promotion of disproven claims risks discouraging parents from vaccinating their children. “Spreading this misinformation will needlessly cause fear in parents of young children … putting their children at risk to contract and potentially die from vaccine preventable diseases,” she said.

Connecticut has maintained one of the highest vaccination rates in the country, with 98.2 percent of kindergarten students receiving the MMR vaccine during the 2024–25 school year, according to the state. While more than 1,700 measles cases and three related deaths have been reported nationally in 2025, Connecticut is among only seven states and Washington, D.C., with no confirmed cases this year.

Health officials stressed that vaccine risks remain far lower than the dangers posed by diseases such as measles, which hospitalizes about one in five patients and kills up to three of every 1,000 infected.