Anti-vaccine groups have seized on the allegations to contend that scientific studies disproving the vaccine link to autism are wrong. Those groups have long argued that thimerosal, a preservative in some vaccines, can cause autism, as can the MMR vaccine for measles, mumps, and rubella.
"I think it is quite significant," said Dan Olmsted of the Age of Autism. "I think someone allegedly capable of ripping off his own university by forging documents from the CDC is capable of pulling off anything."
The CDC and coauthors of the two studies published in major U.S. medical journals maintain the studies remain valid.
"CDC is aware of the allegations by Aarhus University against Poul Thorsen," agency spokesman Tom Skinner said in a statement. Federal authorities are investigating.
Skinner noted that Thorsen was one of many coauthors on peer-reviewed studies looking at autism, cerebral palsy, Down syndrome, and alcohol use in pregnancy.
"We have no reason to suspect that there are any issues related to the integrity of the science," Skinner said.
Efforts to reach Thorsen for comment by phone and e-mail this week were unsuccessful.
In a statement, Drexel University said that Thorsen was an adjunct at its School of Public Health from Dec. 11 until "he resigned his appointment with the school of public health on March 9, 2010."
Drexel's statement noted that his role was limited to serving as a member of the thesis committee of one doctoral student.
"To our knowledge, Dr. Thorsen has performed no other work directly connected to Drexel while holding a title at Drexel University," the statement said.
In 2002, Thorsen was the sixth named author of a study published in the New England Journal of Medicine that analyzed whether where is a connection between the MMR vaccine and autism by examining 537,303 children born in Denmark from 1991 through 1998.
