Smallpox no longer exists in the general population. We eliminated it via vaccines. There is absolutely no need for a drug to treat smallpox with this one exception.
Smallpox is alive and well in biological warfare labs in North Korea, China, and probably Russia and perhaps a few other nations but that is not certain. The first two are certain.
Funny story. Circa 1972 I was flying from Ecuador to Columbia. My smallpox vaccination was not current. Smallpox then was a disease that still existed in the world. The most polite medical officials took me aside and gave me the inoculation and wished me on my way and welcome to Columbia. It took less than five minutes.
I ‘fear’ smallpox is in labs in North .Korea, China, etc. but I am NOT certain it is. Officially it is only at CDC in Atlanta and one lab in Russia. At the time Soviets weaponized it they were on poor terms with China and probably wouldn’t have shared it. Scenarios with them sharing with Saddam or North Korea were more plausible. From where it may been subsequently been shared further. Any certainty of current existence beyond the official two sites would have to come from well classified intelligence. I’m not aware of any public releases on that front although I certainly hope we’re trying to know. Meanwhile having robust countermeasures on paper keeps potential bad actors concerned any release may fizzle resulting in intact, righteously p*shed Americans.