The one flaw in the logic, however, is that we have more global travel now. We also have a lot of people pretending it isn't happening and keeping the spread going. It looks like 2023 would have been a better prediction.
Never mind. The series is a Science Fantasy and reading is a good way to escape the realities of this awful disease. It's nice that time travelers can just slip away to better times.
Many of the vaccines we receive as children might help fight off these infections, but how effective are they decades after the inoculations? Most of us don't travel to places where there are still outbreaks. The Western world often forgets how protected we have become from problems that still exist in third world countries.
Luckily for my own characters, their time traveling abilities are limited to their own lifespans. Most of them will never see times when eradicated diseases regularly killed people, though if you've read the series you'll know there is a way to travel through relays beyond your own time.
Imagine if a modern time traveler took Covid-19 back to an earlier time. What would happen to change an unchangeable future? Just trying to think it out gives me a headache.
Stay safe everyone.