evidence: Vaccines containing adjuvants are tested extensively in clinical trials before being licensed. Aluminum salts, monophosphoryl A (a detoxified bacterial component), QS21 (isolated from the bark of Quillaja Saponaria trees), CpG (nucleic acids), and squalene (a compound of the body’s normal cholesterol synthesis pathway) are used as adjuvants in the United States. The quantities of aluminum present in vaccines are low and are regulated by the Center for Biologics Evaluation and Research (CBER). [...] Why Is Aluminum in Vaccines? Isn’t It Dangerous? [...] Although aluminum at high doses can cause a variety of clinical manifestations, the quantity of aluminum in vaccines is too small to cause a direct toxic effect. Indeed, the quantity of aluminum in biological specimens from those receiving aluminum-containing vaccines is indistinguishable from unvaccinated subjects. The concern that aluminum in vaccines might be associated with a rare autoimmune disease called macrophagic myofasciitis has been refuted by previous studies.