The scientific evidence is very clear: There’s no link between vaccines and autism, and vaccines are generally safe, although they can cause some rare, typically minor side effects.
In a broad analysis of vaccines and their adverse effects, the Institute of Medicine (IOM) in 2011 concluded vaccines are not linked with autism or other serious medical problems, including type 1 diabetes. The study looked at vaccines for various diseases, including MMR (mumps, measles, and rubella), HPV, and hepatitis A, and found no serious side effects to be prevalent. But the report did identify some other, less-serious side effects, such as fever and allergic reactions.
IOM’s findings align with previous research. One meta-analysis published in 2009 in the Oxford Journals concluded vaccines and thimerosal, a mercury-containing compound found in some vaccines, do not cause autism. Another study published in 2010 in Pediatrics found timely vaccination produced no adverse effects on neuropsychological outcomes seven to 10 years after the vaccines were administered.
The Lancet in 2010 also retracted a 1998 study that claimed to tie MMR vaccines to autism. The study received widespread criticism from the scientific community, and an independent regulator found the study seriously flawed. It was, however, circulated for years by anti-vaccine critics as proof of their claims.
Public health experts say it’s important for everyone to know vaccines are safe and effective so enough people get vaccinated to reach herd immunity, when so many people are immunized that diseases have a difficult — if not impossible — time finding hosts to spread to and therefore can’t turn into serious public health threats.