Vaccine Adjuvans

What is an adjuvant?

An adjuvant is a substance that enhances and helps the ability of an antigen to stimulate the immune system. An antigen alone does not stimulate a significant response. Less vaccine antigen (inactive bacteria, virus or toxin) is needed when paired with the right adjuvant.

What is VAC?

Aluminum hydroxide gel VAC grades for adsorption (Pseudo-Boehmite form) are used as an adjuvant in human and animal vaccines. It is used to bind negatively charged antigens.


Its functionality is to adsorb a large range of proteins and inactivated viruses. At pH of preparation of vaccines around 5-7, Pseudo-Boehmite gels have the property to:

  • Adsorb negatively charged antigens
  • Slow the release of an inactivated virus or bacteria
  • Activate and stimulate the immune response
  • Create a more rapid development of high titered and long-lasting antibody responses after primary immunization

Adsorbent properties are related to surface area and surface groups, the hydroxyl groups can

Aluminium Hydroxide Adjuvants surface charge is pH dependant.

Aluminium Hydroxide gels used as Vaccine Adjuvants:

  • They are called Aluminium Hydroxide but they are not chemically Al(OH)3
  • They are poorly crystalline Boehmite (Pseudo-Boehmite): AlO(OH), nH2O: Aluminium oxyhydroxide
  • Composed of fibrous primary particles of a few nanometers, Pseudo-Boehmite has adsorption properties and a large surface area (around 500 m2/g)


Our principal SPIPharma offers the ability to customize the VAC grades to optimize the performance with your antigen or match your current adjuvant.

Adjuvants surface charge

Example applications

Human applications for vaccines, blood fractionation and systemic allergen immunotherapy

Example vaccines:

  • Hepatitis A
  • Hepatitis B
  • Yellow fever
  • Diphtheria
  • Tetanus
  • Poliomyelitis

For blood fractionation, the Aluminum based adjuvant is used to remove certain serum components during a purification process due to its protein adsorption capabilities.

Today, most subcutaneous allergen immunotherapy is performed with Aluminum, Al(OH)3, as adjuvant.

Veterinary applications for vaccines for livestock and companion animals (production from inactivated virus)

  • Highly contagious diseases:
    Foot and Mouth Disease, Classical Swine Fever, Aujeszky's Disease (Pseudorabies), Infectious Bovine, Rhinotracheitis (IBR), Avian influenza
  • Swine, Poultry diseases
  • Multiple species diseases: Anthrax, Bluetongue, Brucellosis (Brucella abortus), Leptospirosis, Paratuberculosis, Q fever, Rabies, Rinderpest, West Nile fever

Vaccine Adjuvants