Cannot fathom the need for additives in a vaccine that requires refrigeration but I suppose there might be something to keep any little parts fluid throughout the vial...not that a little shake wouldn't do the same thing.
It just so happens that early vaccines were hard to be made effective enough for a large population. One person can be immunized, over time, with any crude or purified germ coat extract, such as a Unique proteins or polysaccharides of the microbe.
But, sadly, each individual shot can merely yield a tepid response. So it needs to be repeated until there are neutralizing antibodies. This approach could work for a thousand soldiers on a planned military expedition in an area of risk, but is not good enough for mass vaccinations.
Some of the additives are surprisingly cheap and simple and there only to “stabilize” the ultra-low concentration of the foreign antigen.
But “adjuvants”, that actually serve to BOOST immune response, can even require
killing sharks for their livers to get a unique compound which has strong adjuvent properties turning a poorly antigenic suspension into a super-effective vaccine!
Asher
