Attendees included experts in the fields of autism, pediatrics, toxicology, epidemiology and vaccines. Also in attendance were approximately half a dozen public-health organisations and pharmaceutical companies, as well as eleven consultants to the CDC, a rapporteur, and a statistician. The meeting served as a prelude to vaccine policy meetings held by the Advisory Committee on Immunization Practices (ACIP), which sets U.S. vaccine policy for the CDC. The session was also to serve as the initial meeting of the ACIP work group on thimerosal and immunization.