Earlier quoted context omitted.
Smallpox is roughly as contagious as SARS-Cov2 Delta and therefore more transmossible than the original variant. However those numbers are the unmitigated numbers. Public health and other authority figures have some advantages in fighting smallpox versus SARS-Cov2. IIRC, smallpox is not infectious until the "pox" are visible on the body, greatly improving ability to screen for the disease and the vaccine traditional…
With smallpox so deadly, how did europeans intentionally put it on blankets given to native americans with genocidal intent? were europeans conferred some residual resistance by variants being endemic across europe, but not the americas?
That's a myth, stemming from Howard Zinn. Zinn basically scoured various underground and left-wing pamphlets, some even anti-american cold war propaganda, and collected that all into an underground history, called "A People's History of the United States". It's wildly popular among a certain subset of the population, who take what's written there as gospel.
Zinn never provided a source for the small-pox blanket trope. Not because he invented it (I don't think he did) but because citing propaganda is not a good look for a historian.
When you try to do some archeological digging of these urban legends, the closest thing you can find in terms of real history is a letter from colonial times when there was a mention of this as a possible war strategy by a British administrator, Sir Jeffery Amherst, but there is no evidence anything like this actually happened during the British rule or after independence.
By the time it reached Zinn, it was turned in US cavalry officers actually giving blankets to Indians in the 19th Century. From then it spun out into popular culture. I think it's even included in the Simpsons.