“one day one” is a bit awkward. I’d change either “one” to another word or rewrite the sentence.
Not bad, certainly, but seems a little rapid. The transitions between the disease spreading to the helpless woman to the United States to most of the world are very sudden.
That said, the premise of Antarctica being the last safe haven is a chilling thought (see what I did there?), and leaves a lot of room for a good solid sequel.
Sam Ervin