Why am I thinking about looking at Wang's Wang under a microscope in "The Disease"?
Medically speaking, for just in case, or for when he writes a book about the issues of travelling through unknown space, the Doctor would have kept a sample of Harry's STD in a Stasis cooler which medical Students would be studying for the next thousand years.
All the diseases, all the crew happened upon.
You can't tell me that the doctor wasn't planning some sort of medical experimentation on caretakers corpse eventually? At the very least of they were able to produce a clone with his memories it would have helped their journey so much.