just wait and see

When Europeans first came into contact with the Aborigines of Australia, there were many Aboriginal deaths from the common viruses transmitted by the Europeans. Whenever a historical community that was previously isolated comes into contact with one that isn’t, the isolated community gets incredibly sick because their immune systems are so unprepared.

These days there are talk of superbugs and viruses that have evolved to counteract the best of our antibiotics. If one of those were to come in contact with a primitive individual, that individual would have no chance really.

So you can imagine that in the near future these superbugs probably will have developed further and become commonplace, I.e. the future common cold may need to be combated with an inoculation that does not exist today.

If time travel is theoretically possible (Which I believe it is) then sending someone to the future will expose that individual to the commonplace viruses of the future (Which they have no immune defence to). Similarly, someone that travels back in time to visit us (Say to warn of an imminent global destruction) will expose us to anything that may be lingering around their body. Simply, we are the primitive community that will have no chance.

The moral of the story: We are not prepared for the future.. also don’t travel to the future lol.

Note: I just thought up this, I didn’t copy anyone but I have no doubt that it has been thought up by many other, more intelligent people than I.