Will Antivaxxers end the world by mutating diseases until they cant be fixed by vaccines?

If the disease mutates then the vaccine doesn't work on the new strain...

This is why the flu vaccine is not effective. 

Vaccinating protects you from getting the flu, but unfortunately catching the flu is how your immune system gets stronger. Getting vaccinated will leave you defenseless the instant there is a new virus that can't be vaccinated against. As we are seeing, all the people who took vaccines are dying now.

Generally antivaxxers are and will remain a minority. 

Because most people who end up getting vaccine preventable diseases quickly see the error of their way. There is nothing better than e.g. a measles outbreak to get people getting the measles vaccine. Unfortunately it also means a fair number of people will get unnecessarily the measles with all the risks. 

I wouldn't worry too much about existing diseases mutating. The only one which does that is the flu and can and do develop new vaccines constantly. 

The common cold however is caused by so many different viruses that we probably never will have a vaccine. But then it is also not very dangerous.