I would expect it is usually possible to reduce or remove the adjuvant in exchange for more repeated doses. But immune systems are weird, and I can’t say that confidently
Only live-attenuated vaccines may (sometimes) not need adjuvants. Plus you sometimes have other ingredients acting as adjuvants that are not declared as such. For example mercury is declared as a preservative, not adjuvant, but it performs the same function. Also as of recent they started removing constituents from the ingredient list, that were part of the manufacturing process (e.g. culture media), but are not “intended” part of the final product. If a food manufacturer washes potatoes with iodine for example in order to clean them, he is not required to list that as an ingredient, regardless of whether or not quantities in the final product are relevant.
To put simply without a live virus, the immune system recognizes the would-be antigens as simply garbage molecules, and not as a threat. In order for immunization to work, you need to inject something dangerous like a live virus, aluminium, some kind of toxic protein or cytokine alongside the antigen.
Great questions. I am not knowledgeable about new adjuvants. Here is Derek Lowe on the topic of new adjuvants:
https://www.science.org/content/blog-post/enhancing-enhancers-vaccines
Also,
Many vaccines do not have adjuvants
I would expect it is usually possible to reduce or remove the adjuvant in exchange for more repeated doses. But immune systems are weird, and I can’t say that confidently
Only live-attenuated vaccines may (sometimes) not need adjuvants. Plus you sometimes have other ingredients acting as adjuvants that are not declared as such. For example mercury is declared as a preservative, not adjuvant, but it performs the same function. Also as of recent they started removing constituents from the ingredient list, that were part of the manufacturing process (e.g. culture media), but are not “intended” part of the final product. If a food manufacturer washes potatoes with iodine for example in order to clean them, he is not required to list that as an ingredient, regardless of whether or not quantities in the final product are relevant.
To put simply without a live virus, the immune system recognizes the would-be antigens as simply garbage molecules, and not as a threat. In order for immunization to work, you need to inject something dangerous like a live virus, aluminium, some kind of toxic protein or cytokine alongside the antigen.