A 2002 MMR vaccine study remains valid, according to the journal that published it. One of its co-authors, Danish researcher Poul Thorsen, has pleaded guilty to stealing grant money. Social media posts claiming his plea invalidates the research are incorrect, an AFP fact-check found.
Thorsen pleaded guilty on September 1 to operating a scheme that stole more than $1 million. The money came from the US Centers for Disease Control and Prevention (CDC). His sentencing is scheduled for December 1.
What the MMR Vaccine Study Found
Thorsen was a named author on the 2002 New England Journal of Medicine (NEJM) article “A Population Based Study of Measles, Mumps, and Rubella Vaccination and Autism.” Its authors found “strong evidence against the hypothesis that MMR vaccination causes autism.”
The fraud case centers on wire fraud and money Thorsen illegally laundered for personal use. It does not concern the quality of research produced by Danish agencies, which received funding from CDC grants he helped administer.
Lead Author Says Thorsen Never Had the Data
Kreesten Madsen, the study’s lead author, told AFP in 2025 that Thorsen provided a link to the CDC. Madsen said Thorsen was not central to the project and never had access to its data.
“Acquisition, first analysis, and interpretation of the data was done without Poul Thorsen,” Madsen said.
The NEJM previously told AFP it did not find any issues with the paper, despite Thorsen’s indictment. “The study’s findings remain valid and are consistent with extensive subsequent research showing no link between MMR vaccination and autism,” a spokesperson said.
How the Guilty Plea Spread Online
An image shared September 3, 2026 on Threads cited Thorsen’s plea as proof against the vaccine research. Podcaster Joe Rogan also referenced the case in his September 1 episode.
Clips from that episode spread across X, Facebook, Instagram, TikTok and Rumble. The anti-vaccine advocacy group Children’s Health Defense amplified them.
Later Research Backs the MMR Vaccine Study
The MMR vaccine study is one of many on the question. Years of later research have continued to show no causal link between vaccinations and autism or other neurodevelopmental disorders. In 2020, the Cochrane Review found that MMR, MMRV and MMR+V vaccines “are effective and that they are not associated with increased risk of autism.”
A landmark 2026 study of more than 2.5 million children in the United States also found “no association between MMR vaccination before 24 months and childhood autism.”
David Mandell previously described that body of work to AFP. He directs the Penn Center for Mental Health at the University of Pennsylvania School of Medicine.
“And in all those studies that were well done, we see no association between vaccines and autism,” Mandell said.
Where the Autism Claim Began
Misinformation about the MMR vaccine and Autism Spectrum Disorder largely stems from a 1998 paper by Andrew Wakefield, not from the 2002 MMR vaccine study. The Lancet retracted that study over falsified data, and Wakefield was struck off as a doctor in the United Kingdom in 2010.
A CDC webpage on vaccines and autism once stated that the evidence shows “no link between receiving vaccines and developing autism spectrum disorder.” That text matched assessments from the World Health Organization, the Coalition of Autism Scientists and the Autism Science Foundation. Under Health Secretary Robert F. Kennedy, Jr, the CDC revised the page with language undermining that position.
Public health experts say the combined shot protects children faster and cuts logistical hurdles for parents who may struggle to make multiple appointments. Vaccine guidance now sits beside other contested health policy questions. They range from Medicaid access for mental health care to state healthcare laws and FDA testing for AI medical devices.
Thorsen’s sentencing on December 1 addresses the stolen CDC grant money. The journal’s position is that the 2002 MMR vaccine study’s findings stand.
