ADHD News & Research

Large Danish Study: Autism Not Linked to MMR Vaccine

Researchers used a Danish population registry to disprove the notion that the MMR vaccine can cause autism.

March 5, 2019

New findings published in Annals of Internal Medicine1 have disproved the unfounded theory that the risk of autism is increased by the measles, mumps, rubella (MMR) vaccine. Researchers at Statens Serum Institut in Copenhagen, Denmark, used a nation-wide cohort study of Danish children born between 1999-2010 to determine that the MMR vaccine does not increase the risk for autism in children, subgroups of children, or time periods after vaccination.2

6,517 of the 657,461 children analyzed were diagnosed with autism. A comparison between MMR-vaccinated and MMR-unvaccinated children showed an autism hazard ratio of 0.93 — a less-than-positive correlation. There was also no increased risk for autism after vaccination in subgroups of children defined according to sibling history of autism, autism risk factors or other childhood vaccinations, or during specific periods of time after vaccination.

Researchers state that this study contributes additional statistical power to previous studies and answers questions about susceptible subgroups and autism clustering.


Anders Hviid, Jørgen Vinsløv Hansen, Morten Frisch, Mads Melbye. “Measles, Mumps, Rubella Vaccination and Autism.” Annals of Internal Medicine (Mar. 2019).

“No link found between MMR vaccine and autism, even among children with other risk factors for autism.” Science Daily. (Mar. 2019).