can't remember the name of this book, can you?

i read it at least 2 years ago. the story was about a woman who was on some exploration type expedition somewhere arctic. meanwhile the rest of the world was dying from some disease, except for her and those that she was on the trip with.

in a separate reality people kept disappearing. it turns out that as long as someone was alive that remembered you, you'd live in this alternate reality and finally only the people that the one lady had known in her life were "alive".

does that ring any bells???