Except...a vaccine will always be needed.All of those diseases were going the way of the dodo well before vaccines rolled up, you know how diseases continue? By spreading.
And guess what we can do as an advanced society? Stop the spread of disease!
The pathogens responsible for most diseases doesn't last long outside of the human body, we could basically rid entire nations of specific diseases if we really tried, but then we wouldn't need vaccines.
Tourists can bring them with them.
And war, biological and chemical warfare can happen to your citizenry.
Chickenpox has never been close to eradication. Shingles hasn't either because if there not being eradication for Chickenpox.
The only one I know that has been close to being destroyed is Polio and Smallpox, as well as the Plague.