Vaccine Adjuvants
The goal of vaccination is to generate a strong immune response to an administered, well-defined pathogen component (the antigen) - a response that will provide long-term protection against future or ongoing infections from the same or related pathogens. Unfortunately, the newer and safer recombinant/purified antigens used in modern vaccines are poor at stimulating immune responses when compared to older and more toxic vaccine technologies - which employed live or whole-inactivated microorganisms. Achieving the necessary immune response to a vaccine therefore requires the addition of a second ingredient, called an adjuvant, which is designed to enhance the immune response to the antigen. Adjuvants are used for a variety of purposes in vaccine development including:
- (1) enhancing the immunogenicity of a highly purified or recombinant antigen
- (2) reducing the amount of antigen or the number of immunizations needed to attain protective immunity (antigen “dose-sparing”)
- (3) improving the effectiveness of vaccines in specific, poor vaccine-responder populations - for example in young infants, elderly, or immune-compromised persons
- (4) enabling delivery of vaccine antigens via novel routes not requiring injection - for example by nasal spray (needle-free)
The current gold standard adjuvants for injected human vaccines are various aluminum salts (alum), an adjuvant type that has been in human use for over 80 years. While alum-based vaccines are generally accepted, alum remains a relatively weak adjuvant that induces primarily an antibody response, but little, if any, of the T cell immunity that is needed to achieve long-lasting protective immunity. Moreover, alum’s relatively weak adjuvant effect requires that as much as 1.2mg of alum per dose must be used in intramuscular injections in order to get an immunogenic advantage. Such amounts of alum are enough to cause unpleasant side effects in many vaccine recipients including injection site pain, swelling, ulceration, fever, muscle aches, and allergy. The clinical acceptance of alum is based primarily on its long history of human use which predates current regulatory standards. The lack of alternative adjuvants has necessitated the continued use of alum, despite some questions regarding its safety/efficacy balance. The only reason that alum remains in almost exclusive vaccine use today has been the lack of a safer and at least equally effective alternative.
Vaxiva Product Advantage
Vaxiva’s lead adjuvant technology will be developed first for use in vaccine products for Japan. This adjuvant is the first in history to offer a viable alternative adjuvant to vaccine manufacturers with superior tolerability and effectiveness to alum.More specific information on Vaxiva’s lead technology will be available on this webpage soon.
Please contact Vaxiva directly for further information: info@vaxiva.com