Vaccines adjuvants in 2012

Adjuvants are an essential component of most vaccines, especially the most highly purified, and will probable remain so for many years to come. Their role is to stimulate innate immune mechanisms and thereby activate effectors of the adaptive immune response. Adjuvant aluminum is used in a highly specific form and complies with stringent physicochemical standards. WHO and the FDA, among others, have set strict limits on dietary aluminum intake, based on animal experiments (minimum risk level (MRL) 1 mg/kg/day). Vaccine immunization schedules must deliver no more than 0.85 mg of aluminum per dose. Experimental work with labeled aluminum showed that the amount of aluminum contained in injected vaccines in the standard infant immunization schedule is far below the dietary MRL. Although very small amounts of aluminum are found in brain tissue, there is no firm evidence of a relationship between aluminum and Alzheimer's disease. In particular, in hemodialysis patients having died of encephalopathy and in experimental animals injected with aluminum, brain damage does not resemble that of Alzheimer's disease. Likewise, cognitive disorders associated with macrophagic myofasciitis do not correspond to those of Alzheimer's disease. No clear evidence of neurological toxicity from aluminum contained in food or vaccines has been reported to date. New and experimental non aluminum adjuvants are not intended to replace aluminum salts but rather to develop new vaccines against specific diseases such as malaria, HIV, tuberculosis and certain cancers. The various adjuvants are not interchangeable, being specific to particular vaccines. Efficacy studies of calcium phosphate, a proposed aluminum substitute, have given mixed or contradictory results. Aluminum adjuvants could only be replaced after lengthy and extensive testing, monitoring, and clinical studies (taking about 5 to 10 years). There is no firm evidence linking vaccines or their adjuvants to the onset of autoimmune diseases. Any moratorium on the use of aluminum adjuvants would make the majority of vaccinations impossible, with no firm scientific basis. The resurgence of vaccine-preventable infections would inevitably lead a much higher disease burden than the hypothetical risk of autoimmune diseases or neurological disorders attributed to vaccination.