Can douching with vinegar kill the HIV virus before it infects you?

I do not recommend cleaning used needles with vinegar, nor do I recommend douching with bleach. In fact, I would strongly recommend against douching with bleach or using needles.

The best thing to do would be to use protection and get tested regularly; do not try to make up a post exposure method of killing the virus.

That doesn’t mean that vinegar won’t kill the virus. It is possible, but it isn’t consistently predictable, it isn’t certain, and by all means, it is not even remotely a good method of preventing HIV infection. I mean, if you put the HIV virus into Coca-Cola, for example, the virus will eventually break down. It will eventually break down in vinegar, but you cannot be certain that it will do so in time to prevent infection. HIV infection, in some cases, can happen very quickly. For example, if somebody has an open wound or even a herpes blister in the genital region, and thus has lymphocytes near the surface of the skin, the HIV virus can bond and cause infection even before douching would do any good at all.

The bottom-line answer is this: do not put yourself in that situation in the first place. I cannot emphasize how much using protection properly and getting tested regularly can help you. If you are informed about your sexual health, then you will be healthier, and you will be confident that you are not putting anybody else at risk for contracting a STD.