I hadn't heard the "hemorrhagic smallpox" angle. Sure that wasn't the ChiCom/NK spin? Both of those countries claimed that the US had used "germ warfare" on them, but what I've always read that what stopped them in the winter of '50-'51 was a combination of overextended supply lines and an old paratrooper named Ridgeway.
I just thought it was worth reposting.