I'd like to send my protagonist permanently into the near-ish future. I suspect that something as simple as the common cold could be deadly to my protagonist once we get a little further along.
I am looking for a rule of thumb that there might be, in science or hard science-fiction. Setting aside the following variables:
- Yes, I know everyone's body is different, I haven't been sick for more than a decade while I have friends who are sick every month. I'm just looking for a rule of thumb.
- Yes, it's fine if there's been an advance in medicine, but this is about contraction (and, if there's a rule of thumb used in fiction) of common airborne diseases as we know them today, such as the cold. Assume our daily, urban lives are as they are in the West, just with near-future technological advancement.
- My protagonist came from today and I want her to travel as far into near-future (100 to 200 years) in the same, progressing country, that wouldn't create a quick contraction of a virus or bacteria that could cause major complications.
To avoid this from being too broad: What's the best rule of thumb in worldbuilding/storytelling or historical precedent for how far a person today might travel without being seriously compromised by a common, airborne disease; without imagining completely new diseases.