The measurement and full statistical analysis including Bayesian methods of the aluminium content of infant vaccines.

Background: Aluminium salts are the most common adjuvants in infant vaccines. The aluminium content of a vaccine is provided by the manufacturer and is indicated on the patient information leaflet. There is no independent verification, for example by the European Medicines Agency, of the aluminium content of infant vaccines.

Methods: We have measured the aluminium content of thirteen infant vaccines using microwave-assisted acid and peroxide digestion followed by transversely heated graphite furnace atomic absorption spectrometry. Our data are compared with manufacturer's data using full statistical analyses including Bayesian methods.

Results: We found that only three vaccines contained the amount of aluminium indicated by the manufacturer. Six vaccines contained a statistically significant (P < 0.05) greater quantity while four vaccines contained a statistically significant (P < 0.05) lower quantity. The range of content for any single vaccine varied considerably, for example, from 0.172 to 0.602 mg/vaccine for Havrix.

Conclusions: The data have raised specific questions about the significance of the aluminium content of vaccines and identified areas of extremely limited information. Since aluminium is a known toxin in humans and specifically a neurotoxin, its content in vaccines should be accurate and independently monitored to ensure both efficacy and safety.