In 2013, the National Vaccine Program Office of the U.S. Department of Health and Human Services (HHS) commissioned an update of earlier findings on the lack of evidence to support claims that the Centers for Disease Control and Prevention (CDC) infant/child vaccination schedule was safe. The Institute of Medicine (IOM) committee [was] charged with producing the update. The lack of information on the overall safety of the vaccination schedule was so compelling that the committee then recommended HHS incorporate the study of the safety of the overall childhood immunization schedule into its processes for setting priorities for research, "recognizing stakeholder concerns, and establishing the priorities on the basis of epidemiological evidence, biological plausibility, and feasibility." The IOM also recommended the CDC use its private database, the Vaccine Safety Datalink (VSD), to study the overall health effects of the vaccination schedule using retrospective analyses. Ten years later, the CDC has yet to do such a comparison study, even though it is sitting on a vast repository of data in the VSD, which include comprehensive medical records for more than 10 million individuals and 2 million children. The VSD also contains records for a significant number of unvaccinated children, yet the CDC refuses to compare the health outcomes of vaccinated children to completely unvaccinated children. The CDC also prohibits VSD outside researchers from accessing the VSD data.