I apologize if I’m missing the point you’re making, but trench foot and vaccines are completely unrelated.
Vaccines fundamentally impact viruses. Trench foot is not caused by a virus, or any infection. It’s more akin to frostbite.
We’re really pushing the boundaries of what we can do with vaccines, but the root cause of trench foot is poor circulation, and a vaccine can’t really fix that.
I thought we are making cancer vaccines now. We are literally developing vaccines to fight thrombosis (aka blood circulation).[1] And we have vaccines that work against bacteria, specific toxins, parasites etc. Not sure you and I agree on what a vaccine is or does.