There are only a few ways you can pass on HIV and these are the only ways. You CANNOT get HIV from kissing, cuddling, or sharing drinks, plates or toilet seats.
To pass on HIV there needs to be a direct way for the virus to get into another person’s blood stream - a bit like going through a door. Getting HIV infected blood on your skin, clothes etc is not a risk. It needs to get into your body (through a cut or tear in the skin). HIV can only survive outside of the body for a very short time - less than a minute - so you can’t pass HIV on through dried blood.
HIV can be passed on through:
A really simple way to pass on HIV would be by a blood transfusion, where HIV infected blood is put straight into someone else’s blood stream. In most places in the world now, blood is checked before it is given to other people. In the past lots of people got HIV through blood transfusions but this was before it was known how the virus was passed on.
If an HIV positive person has sex without a condom, HIV can get into the other persons blood because it lives in the semen and vaginal fluid. There does need to be a tear or graze in the other person for the HIV to enter into their body. A condom stops any semen or vaginal fluid getting to the other person, and it also stops unwanted pregnancy and getting other sexually transmitted infections.
If one person has HIV and they inject themselves with a needle, and then another person injects themselves with the same needle directly after, they can pass on HIV. So never share needles.
HIV can be found in breast milk, so if a mother has HIV it is recommended she shouldn’t breastfeed her baby unless it has been advised as safe to do so by a medical professional.