HARTFORD, Conn.— The Connecticut Department of Public Health refutes the claim that vaccinations could cause autism in infants. Vaccines are held to the highest scientific standards as they are given to healthy individuals. Every vaccine recommended for infants and children has undergone extensive research, including clinical trials, to ensure it is safe and effective. Once approved, vaccines continue to be monitored for safety.
Decades of high-quality studies show no link between vaccination and autism, and the small risks of vaccination are vastly lower than the risks from disease. The few studies that suggest such a connection have either been fully retracted or widely discredited due to serious methodological flaws, small or biased samples, or failure to meet basic standards of scientific rigor, replication, and peer review. The medical consensus remains clear — vaccines provide strong, reliable protection with an excellent safety profile.
Studies on Vaccines and Autism:
- 2002 Danish study of more than 500,000 children showed no difference in the rate of autism diagnosis between MMR vaccinated and unvaccinated children.
- A 2006 Canadian study involving over 27,000 children showed the incidence of pervasive developmental disorder increased while MMR vaccination coverage decreased.
- A 2015 U.S. study involving more than 95,000 siblings of children diagnosed with autism spectrum disorder (ASD) found MMR vaccination was not associated with increased diagnosis of ASD, even among high-risk infants with an older sibling with ASD.
"In Connecticut, our message is clear and consistent with recent decades, and backed by scientific data," said DPH Commissioner Manisha Juthani, M.D. "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. Despite this recent political development fueling vaccine hesitancy, the scientific consensus remains clear and overwhelming.”
“The Centers for Disease Control and Prevention website has been changed to promote false information suggesting vaccines cause autism,” said American Academy of Pediatrics President Susan Kressly, M.D. “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. Anyone repeating this harmful myth is misinformed or intentionally trying to mislead parents. We call on the CDC to stop wasting government resources to amplify false claims that sow doubt in one of the best tools we have to keep children healthy and thriving: routine immunizations. The American Academy of Pediatrics stands with members of the autism community who have asked for support in stopping this rumor from spreading any further.”
“At this point it’s not about doing more studies; it’s about being willing to accept what the existing study data clearly show. Spreading this misinformation will needlessly cause fear in parents of young children who may not be aware of the mountains of data exonerating vaccines as a cause of autism and who may withhold vaccines in response to this misinformation, putting their children at risk to contract and potentially die from vaccine preventable diseases,” said Alison Singer, president of the Autism Science Foundation.
In Connecticut, vaccination coverage is high, with 98.2% of kindergarten students receiving MMR vaccination in the 2024-25 school year. However, vaccination rates have declined nationally resulting in over 1700 cases of measles in the US in 2025 and 3 measles deaths. Connecticut is only one of seven states and D.C. that has not had a case of measles in 2025. Vaccination is far safer than natural infection: measles infection alone hospitalizes about 1 in 5 cases and kills 1–3 per 1,000 persons, while serious vaccine reactions are extraordinarily rare.
If you have any questions about the safety of childhood vaccinations, please contact your pediatrician or other qualified health care professionals.
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