Doxycycline is a controlled drug so prescription is compulsory.

This is my first time knowing that cancer is contagious via kissing.

Its quite subjective in the reality-wise..

That's good to have that statistic for bencmarking purpose, but still - for me - its boil down to individual or socialeconomic scale which is highly variable.

If the receptive or insertive individual is a HIV positive but on medication, with latest reading high T4 and low VL, sure. That number is achievable.

But if the individual is diagnosed with HIV positive but defaulted everything, I both personal and professionally think it is not as low as what you describing as chance of hitting 4D.