Poul Thorsen, a Danish researcher whose work contributed to influential studies finding no association between vaccines and autism, is expected to plead guilty to fraud on September 1, bringing renewed attention to his role in research frequently cited in the vaccine-safety debate.
Thorsen was involved in major Danish epidemiological studies examining whether childhood vaccination was associated with autism. The research included studies concerning the MMR vaccine and thimerosal-containing vaccines, and the findings were subsequently cited by the US Centers for Disease Control and Prevention (CDC) and others as evidence against a causal relationship.
However, Thorsen later became the subject of a US federal criminal case involving research funding administered through the CDC.
Federal prosecutors accused him of diverting more than $1 million in grant money intended for research projects. The case alleged that Thorsen submitted fraudulent invoices and other documents to obtain funds which were then used for personal purposes.
His expected guilty plea will inevitably raise fresh questions about his credibility and the degree to which his conduct should affect assessments of research with which he was associated.
🚨 Poul Thorsen, a researcher whose work was used to reassure millions of parents that vaccines do not cause autism, is expected to plead guilty to fraud on Sept. 1.
Thorsen worked on major studies examining vaccines and autism that were cited by the CDC and became part of the… pic.twitter.com/dtYW048s8I
— Children’s Health Defense (@ChildrensHD) August 24, 2026
Critics of vaccine policy have long argued that parents questioning a possible relationship between vaccination and autism were told the scientific evidence was sufficiently strong to settle the issue.
“For years, we’ve been told not to question the science on vaccines and autism,” wrote the Children’s Health Defense. “We were told the evidence was overwhelming and the people conducting the research could be trusted.”
“When the integrity of the people producing that science comes into question, so should our willingness to accept their conclusions without scrutiny,” the organisation said.
Thorsen’s anticipated September 1 plea could therefore reopen debate not simply about his personal conduct, but about how influential scientific findings are scrutinised when researchers involved in producing them later face serious questions over their integrity.
