From 3News in New Zealand
Until now, sex educators and researchers have been assuming that in order to transmit HIV, there needed to be some sort of break in the skin. That made a lot of sense given that HIV is a blood-borne disease and that it can be transmitted through blood contact.
There’s now research that shows that HIV can enter through the lining of the vagina, even if it’s intact. The virus seems to target skin that has recently shed the outer layer, which would then be less resistant to attack.
Of course, that doesn’t mean that the virus can’t also be transmitted through breaks in the skin. One explanation for why HIV is can be transmitted through anal sex is that the lining of the rectum is more delicate than the lining of the vagina, so it’s more likely to have microscopic tears that the virus can pass through. And they haven’t done the same research on rectal tissue yet, although I’m pretty sure that someone will.
Fortunately, condoms still work to reduce the risk of HIV infection. Make sure you use lube with them- that makes condoms less likely to break and more comfortable, too. Not all condoms are the same, so check out our helpful article on choosing a condom and this one on making safer sex fun.