Though the NVICP had existed since 1988, it was not designed to handle the thousands of cases it received from 1999 to 2007, which led to the establishment of the Omnibus Autism Proceeding in 2002.

In support of this hypothesis, the Cedillos' witnesses relied on the reported detection of measles virus in Michelle's gastrointestinal tract by John O'Leary's Unigenetics laboratory in Dublin.

However, the government's expert witnesses conclusively demonstrated that O'Leary's positive results were caused by contamination in the Unigenetics lab rather than an actual infection.

[12] In the Cedillo case, her family claimed that Michelle was normal until receiving her vaccines, as evidenced by a number of videos of her between the age of 6 and 8 months.

They also argued that thimerosal-containing vaccines degraded her immune system, which made it possible for the measles virus to infect her and cause autism and the other health problems she has, which include inflammatory bowel disease, glaucoma and epilepsy.

Other experts who testified on behalf of the state included Edwin Cook, a psychiatrist, Diane Griffin, a virologist at Johns Hopkins University, Stephen Hanauer, a gastroenterologist, Christine McCusker, a pediatric immunologist, Brian Ward, a virologist who, along with Fombonne, published some research which failed to replicate the Unigenetics lab's results, and Max Wiznitzer, a pediatric neurologist.

Their witness that day was gastroenterologist Arthur Krigsman, who testified that his opinion in the case depended on whether measles virus had really been detected in the intestinal tissue of Michelle Cedillo and other children with autism by the Unigenetics lab, using a study conducted by him, Dr. Hepner, Steve Walker, and Jeff Segal as evidence that the Unigenetics lab's results were reliable.

He also, like Dr. Hepner, testified that the Unigenetics lab was reliable and followed appropriate measures to prevent contamination, stating "that the laboratory of Dr. John O'Leary, Dr. Orla Sheils, and their colleagues has a good reputation.

"[22]: 86 One of the key lines of evidence presented by the Cedillo family was that Michelle was developmentally normal before she received the MMR vaccine.

However, Eric Fombonne testified that Michelle "... displayed early signs of autism clearly visibly on family video taken prior to her receiving the MMR vaccine.

"[27] Jeffrey Brent, the past president of the American Academy of Clinical Toxicology, was invited to testify about the potential role of thimerosal-containing vaccines in triggering Michelle's autism.

He stated that "there was not a single study indicating that any form of mercury could cause serious neurological symptoms in the dosages that were used in vaccines" and criticized Aposhian's use of in vitro studies and his equating them to what happens in the actual animal, arguing that "the exposure to a cell in a petri dish was far more likely to cause damage than an equivalent dosage in a living system."

"[28]: 2360  Brent concluded by testifying that thimerosal could not have degraded Michelle's immune system to the extent that when she was vaccinated with MMR nine months later, it caused brain damage, saying "That couldn't possibly be the case.

This claim was based on results from O'Leary's Unigenetics lab, and was examined by Stephen Bustin, a world-renowned expert on polymerase chain reaction who has authored a number of scientific papers on the subject, as well as a book entitled A-Z of Quantitative PCR.

[35] For this reason, Bustin concluded that it was a "scientific certainty" that none of the children's samples analyzed by the Unigenetics lab actually contained the measles virus.

"[38]: 6  Ward also noted that Krigsman had cited research conducted by Vijendra K. Singh of Utah State University which had concluded that more than 80% of children with autism had elevated measles antibodies.

In his decision, George Hastings noted that, unlike Aposhian, Jeffrey Brent, who testified that there was no evidence that children with autism were uniquely susceptible to mercury exposure, was a medical doctor.

[43] Hastings, in his decision, noted that "all of the petitioners' causation theories depend upon the validity of certain testing that purported to find evidence of persisting measles virus in the biological materials of Michelle and a number of other children with autism.

"[22]: 45 With regard to the Michelle Cedillo case in general, Hastings concluded that "The evidence was overwhelmingly contrary to the petitioners' contentions.

[46] In response to the second rulings in 2010, SafeMinds stated, "The denial of reasonable compensation to families was based on inadequate vaccine safety science and poorly designed and highly controversial epidemiology.

"[48] On the other hand, vaccine scientists praised the ruling, with Paul Offit stating "the autism theory had 'already had its day in science court and failed to hold up.'"

"[47] The Department of Health and Human Services released a statement saying that "Hopefully, the determination by the special masters will help reassure parents that vaccines do not cause autism.

"[49] After the ruling, Keelan and Wilson wrote that, in contrast to those who argued that the proceedings gave unnecessary publicity to the scientifically unsupported vaccine-autism hypothesis, "the NVICP was successful in its management of these proceedings and met the intent of the original legislation to protect the integrity of the vaccine supply, maintain public confidence in immunization, and provide those injured with a fair hearing.