How is it that shots, for like HPV and chicken pocks, work for your whole life?

A vaccine is where a dead or inactive form of a virus is injected into your body so that your immune system can see it and develop antibodies to fight it off without being under attack. This is why after a vaccination you might feel poorly for a few days - your body responds as if it is infected. So basically, when you are under attack from this virus you don’t get sick since your body instantly recognises the virus and quickly makes antibodies to defend itself. When you get a vaccine it vaccinates you forever. It doesn’t wash away, it’s permanent. The problem is that the virus it’s protecting against mutates and is no longer recognised by your body as the same thing, so you’re no longer protected. Viruses like influenza mutate very quickly which is why people need like yearly flu shots. But HPV and Chicken Pox mutate very slowly, so throughout your lifetime the vaccine still recognises it and offers protection.