Use of aluminum-containing adjuvants in vaccines started in 1920’s and 30’s by Glenny et al when alum was used to partially purify protein antigens, mainly tetanus and diphtheria toxoids, by precipitating them in the presence of anions including phosphate, sulphate, and bicarbonate ions resulting in a mixture of compounds, mainly aluminum sulphate phosphate and aluminum hydroxyl phosphate. Such vaccines were called Alum-Precipitated Vaccines and were used for many years. Their use declined over the years mainly due to variability among batches during manufacture. Alum-Precipitated Vaccines were replaced with vaccines adsorbed onto pre-formed gels, mainly Aluminum Oxyhydroxide, Aluminum Hydroxyphosphate, Aluminum Hydroxyphosphate Sulfate.

Recently I made a presentation at a Webinar "Aluminum Adjuvants: Overview and Utilization in Vaccine Manufacturing" organized by PATH and shared my experience with these adjuvants.
Key discussion points included:
·      All aluminum-containing adjuvants are “Alum”?
·      Act by “Depot” formation at the site of injection?
·      Adsorption of antigens important parameter for the efficacy of the vaccines?
·      In-use in human vaccines for almost a century and are the benchmark to evaluate new adjuvants.
·      Strong adjuvants for mice and guinea pigs – not sure about adjuvanticity in humans
·      Aluminum hydroxide and aluminum phosphate have different physical characteristics and adsorption properties.
·      Manufacturing methods and formulation affect physical characteristics and adsorption properties.
·      Testing for “Consistency in manufacture” of vaccines adsorbed onto aluminum-containing adjuvant. 

Please see the full presentation at the link below.

https://www.linkedin.com/posts/rajesh-k-gupta-73a83911_aluminum-adjuvants-myths-perceptions-and-activity-7242565254956683265-6oVD?utm_source=share&utm_medium=member_desktop