Q. What is squalene? Why was it used in vaccines?
A. Squalene itself is produced in the body when cholesterol is converted to fat. It is commonly found in certain cosmetics and foods.
Since the Gulf War, one group of researchers has reported finding antibodies to artificial squalene in Gulf War veterans with unexplained illnesses and has suggested that squalene, or antibodies to squalene, may have contributed to these illnesses. These researchers believe that squalene was used a drug adjuvant.
Adjuvants are substances included in some vaccines in order to improve the immune response to these vaccines. Not all vaccines contain adjuvants; some don't need them to produce protection in recipients. Aluminum compounds are common adjuvants in licensed vaccines and have been used safely for many years. Some of the vaccines given to servicemembers during the Gulf War deployment, including the anthrax, botulinum toxoid, hepatitis B, and tetanus-diphtheria vaccines, contained aluminum compounds as adjuvants.
The Defense Department considered but did not use vaccines containing adjuvants other than aluminum during the Gulf War. According to DoD officials, the use of new adjuvant formulations for the anthrax vaccine was rejected because any alteration in the licensed vaccine would require re-licensure, and DoD would not receive FDA approval in time.