When it comes to the most widely used adjuvant ingredient found within vaccines, aluminum, many questions have yet to be answered, particularly when it comes to where the aluminum goes after injection, an issue known as biopersistence.
One reason this question arises is because a causative role has been established in what's known as macrophagic myofasciitis (MMF) lesion in patients who have myalgic encephalomyelitis, or brain inflammation. Myalgia, arthralgia, chronic fatigue, cognitive dysfunction, dysautonomia, and autoimmunity have been temporally linked to aluminum adjuvant-containing vaccine administration (Gherardi and Authier, 2003; Authier et al., 2003; Exley et al., 2009; Rosenblum et al., 2011; Santiago et al., 2014; Brinth et al., 2015; Palmieri et al., 2016).
"Evidence that aluminum-coated particles phagocytozed in the injected muscle and its draining lymph nodes can disseminate within phagocytes throughout the body and slowly accumulate in the brain further suggested that alum safety should be evaluated in the long term."