Dr Mattie Timmer (Victoria University of Wellington) and Dr Bridget Stocker (Malaghan Institute) describe an adjuvant as a substance that is added to a vaccine to make that vaccine more effective. An adjuvant alerts the immune system to the vaccine, making the immune response more immediate and specific to the antigen in the vaccine.
DR MATTIE TIMMER
An adjuvant is a substance that is added to a vaccine to send off a danger signal to your immune system so that you invoke an immune response, and an immune response is then taking up the vaccine itself to get a very specific response to the antigen that is added together with the adjuvant, so you become immune to whatever antigens you have added. So an adjuvant itself does not give you immunological memory or anything like that. It just sends out a danger signal and so that your immune system is prepared to, when it is added together with the adjuvant, it will give an immune response.
DR BRIDGET STOCKER
It’s like a tickle. It’s like lets tickle the immune system to get it going. The true sense of an adjuvant it’s just something that enhances an immune response, so it turns it up. And like with TB I guess you could say, because it’s such a sneaky bacteria, you need to have quite a rapid immune response to it and by having an adjuvant, it makes the immune response a lot more robust and immediate I guess. So you are better able to destroy the bacteria.
Most vaccines actually have some kind of adjuvant added. In a normal vaccine, they add alum. They don’t even know how the alum works, but you have to have it otherwise your immune system doesn’t respond in the way it should.
James Gathany, CDC Centres for Disease Control & Prevention