Treatment with aluminium adjuvanted vaccines does not appear to induce serious or long-term health outcomes, suggest the results of a systematic review. Local hypersensitivity reactions, such as persistent nodules and granulomas, are the most consistently recorded reactions.
“Current evidence does not support causal associations between aluminium adjuvanted vaccines and serious or long-term health outcomes, including autism spectrum disorder (ASD), type 1 diabetes mellitus, asthma, and other chronic conditions,” the researchers said.
Fifty-nine studies, including 37 case series, 11 randomized controlled trials (RCTs), nine cohort studies, and two ecological studies, were included in the review. [BMJ 2026;393:e088921]
High-quality evidence from RCTs and large cohorts consistently showed that aluminium adjuvanted vaccines did not significantly correlate with serious or long-term health outcomes, such as asthma, ASD, and other chronic conditions. Studies on macrophagic myofasciitis were small and limited, with no credible evidence of a causal relationship (very low certainty).
Some patients who received diphtheria-tetanus-pertussis vaccines developed localized persistent nodules or granulomas, consistent with delayed type hypersensitivity (<1 percent, self-limited; moderate to low certainty).
High-certainty RCTs also found no consistent risk increase in common adverse events, such as headache and myalgia, among patients who received aluminium adjuvanted formulations. In cases where differences were noted, most were small and mild to moderate in severity.
“Evidence was dominated by methodologically limited studies, with most case series and ecological studies at serious or critical risk of bias,” the researchers said. “Conclusions are primarily supported by higher quality RCTs and cohort evidence.”
Vaccine safety
The current findings are consistent with those of previous systematic reviews and post-licensure surveillance evaluations, which found on elevated risks of chronic diseases attributable to aluminium adjuvanted vaccines. [Wkly Epidemiol Rec 1999;74:337-348; Wkly Epidemiol Rec 2012;87:281-287; Lancet Infect Dis 2004;4:84-90; Crit Rev Toxicol 2014;44:1-80; Pediatrics 2026;157:e2025074874]
“The positive correlations reported in the two ecological studies are limited by their inability to control for confounding and absence of individual level exposure data, contrasting with the large Danish cohort included in this review and several large epidemiological studies finding no association between vaccination and ASD,” the researchers said. [Ann Intern Med 2025;178:1369-1377; Lancet 1999;353:2026-2029; N Engl J Med 2002;347:1477-1482; JAMA 2015;313:1534-1540]
The present systematic review followed the PRISMA 2020 guidelines and searched six databases and trial registries from inception to 3 March 2023, then updated to 27 November 2025. Reference lists of eligible studies were also screened.
Two reviewers screened studies (with artificial intelligence assistance for the 2023‒2025 update), extracted data, and assessed risk of bias. They rated the certainty of evidence using GRADE.
“Ongoing investment in higher quality primary research remains important given the predominance of uncontrolled case series, the limited number of long-term population-based studies, and persistent evidence gaps for rare or delayed outcomes,” the researchers said.
“Further research should examine individual susceptibility factors including sex, ethnicity, family history, adjuvant type, and aluminium dose, while accounting for total exposure from non-vaccine sources such as diet, antacids, breast milk, and formula,” they noted.