Adjuvants stimulate increased, nonspecific immunity and are included in many "killed" vaccines. Until October 16, all adjuvants in licensed vaccines in the US were aluminum salts. They are included in all tetanus, Hepatitis A and B vaccines, anthrax vaccine and others.
Thimerosal is a compound composed of 50% mercury which has been included in killed vaccines to prevent growth of contaminating microorganisms. Due to concerns about its known toxicities and the large doses of injected mercury that were administered when children received multiple vaccines on the same day, it was mostly removed from vaccines starting 10 years ago. Most killed vaccines only include about 5% of the amount of thimerosal they previously contained, or one microgram of mercury.
ASO3 is a new, more powerful adjuvant included in Cervarix, an HPV vaccine that received FDA approval on October 16. You can anticipate that this approval will start opening the floodgates to approval for many new vaccines containing ASO3 and related, powerful adjuvants.
Now that Cervarix is approved, the public may have greater access to the data used to support licensure via Freedom of Information Act requests.