Smallpox vaccination campaigns were sometimes met with hostility, I believe. The book "Dissolving Illusions: Disease, Vaccines, and the Forgotten History" by Suzanne Humphries, MD and Roman Bystrianyk delves into the truth behind the initial efforts to "eradicate" smallpox via vaccines. That any benefit exists to vaccination does not seem clear to me.

I'd like to point out that the vaccinia virus used to make smallpox vaccines is not an attenuated version of "smallpox virus" but a different virus which reportedly may protect one from smallpox.

Few people today are vaccinated against smallpox, unless in certain professions or the military, apparently.

I would wonder if a resurgence of smallpox is possible today and if vaccinated people are protected at all really. Generally speaking it seems that smallpox has had historically devastating outbreaks from time to time, leading me to wonder what the underlying natural immunity is. Bubonic plague disappeared after a while, and it seems to me that survivors may have passed on whatever traits lead to their ability to survive it. Does that possibility exist with smallpox?

Interestingly to me, various strains of vaccinia virus are apparently used in vaccine development.