A systematic review ¹ assessed the adverse events after exposure to aluminium-containing vaccines against diphtheria, tetanus, and pertussis (DTP), alone or in combination, compared with identical vaccines, either without aluminium or containing aluminium in different concentrations.

The review included 35 reports of studies with three randomised trials, four semi-randomised trials, and one cohort study. A meta-analysis was performed of data from five studies around two main comparisons (vaccines containing aluminium hydroxide vs no adjuvant in children aged up to 18 months and vaccines containing different types of aluminium vs no adjuvants in children aged 10-16 years). In young children, vaccines with aluminium hydroxide caused significantly more erythema and induration than plain vaccines (odds ratio 1.87 [95% CI 1.57-2.24]) and significantly fewer reactions of all types (0.21 [0.15-0.28]). The frequencies of local reactions of all types, collapse or convulsions, and persistent crying or screaming did not differ between the two cohorts of the trials. In older children, there was no association between exposure to aluminium-containing vaccines and onset of (local) induration, swelling, or a raised temperature, but there was an association with local pain lasting up to 14 days (2.05 [1.25-3.38]). There was no evidence that aluminium salts in vaccines cause any serious or long-lasting adverse events.

A review ² assessed the current knowledge of aluminium-adjuvanted vaccines and evaluated them to be efficient and safe. They increase immune response induced by the vaccine antigens by mechanisms eg. a depot effect at the injection site, activation of the complement and stimulation of the macrophages. Exposure to aluminium content in vaccines is substantially lower than exposure originating from a diet. In Europe, the maximum acceptable amount of aluminium in vaccines administered to humans, is 1.25 milligrams per human dose; the exact concentration per human dose in most vaccines is even two-three times lower.

WHO Global Advisory Committee on Vaccine Safety (GACVS) noted, that are no scientific evidence of any harm related to aluminum-adjuvanted vaccines.