I don't know where to ask this, Google throws propaganda at the question.
For reasons of travel, I now have to be vaccinated to enter a certain country. So if one has to choose, which is safest?
EDIT - just to clarify, by safe I mean less likely to damage. Vaccine effectiveness isn't a variable here.
Ivermectin
Side-note, you can get vitamin D for free by exposing your skin to sunlight.
So the real advice is as follows: Go outdoors, be fit, eat a balanced diet.
Depends on your skin color.
Pretty racist, huh?