hello, i had some questions about the post you made abt hiv transmission, you said that the risk of contracting hiv from someone who is hiv positive but not receiving treatment is quite low, but if that is the case why was there such a huge epidemic of it? and, you also said that the risk of getting hiv from a partner who knows that they are hiv positive is lower than getting it from someone who is unsure, why is that? i apologize if i have misunderstood or misinterpreted what you said
that’s a big question! there are a lot of reasons for the epidemic, then and now, and i’ll try to cover the most relevant ones, in fairly broad strokes.
the virus had many years to spread before we were able to do anything about it — before we knew what kind of safer sex precautions would work, and before we had the treatments that make it less infectious.
HIV has a long incubation period, meaning it can be asymptomatic for about ten years on average, so it was spreading for years before the syndrome even started to be officially noticed in 1981. then after that, it took a while to identify the virus, to create a test for it, and to determine that it was sexually transmitted, and then a while after that to start coming up with safer sex recommendations, and then even longer after that for those recommendations to have real science behind them. furthermore, it wasn’t until 1996 that truly effective treatments became available. much of this delay was due to the U.S. government neglecting AIDS research and education because the populations that were hit hardest at first were seen as undesirable and disposable.
there was also a different sexual culture at the time, particularly among gay and bi men. it’s hard to imagine when you’ve grown up amid fear of AIDS, but in the pre-AIDS era of modern medicine, it wasn’t a big concern that sex could kill you. STIs were generally treatable, and since gay men didn’t have to worry about pregnancy, they rarely used condoms. (and of course, straights often didn’t — and don’t — use them either.) once they understood what was happening, gay and bi men became pioneers of safer sex, but by then, the epidemic was already well underway.
the virus is also spread through needle sharing by intravenous drug users. this has a higher transmission rate, and the effects of poverty and addiction make this mode of transmission complicated to address.
it’s also important to realize that transmission rate varies widely between different HIV+ people and scenarios. a HUGE factor is viral load — the number of copies of the virus in your blood. HIV treatment lowers your viral load, and with careful treatment, most people can get their viral load so low it’s undetectable. as long as it stays that way, they can’t transmit the virus. but the higher your viral load, the higher the risk of transmission.
because early diagnosis and treatment lowers transmission risk, access to quality education and health care is crucial in stopping the spread of HIV. as you might imagine, this means HIV can spread more easily in marginalized communities with higher poverty and less accessible (or inaccessible) health services. this is one example of how structural factors outside of people’s control can contribute to the epidemic.
other factors include the type of sex act — generally, the receptive partner is at a higher risk than the insertive partner and anal sex is riskier than vaginal sex — use of condoms or PrEP, and the presence of other STIs.
so first, that 1 in 1250 risk (for receptive vaginal sex without a condom or PrEP or antiretroviral therapy) is still significant in the aggregate, even if it’s way lower than we tend to assume. but change around some of these factors and the partner’s specific viral load, and the risk can be higher. you can see how this works with this CDC tool.
one other thing you’ll see on that site is “acute HIV.” acute HIV refers to the period in the first several weeks after contracting HIV, when viral load is temporarily VERY high. if you’re having receptive sex and your partner is in the acute infection stage, for vaginal sex that increases the risk from 1 in 1250 to 1 in 172, and for anal sex it increases the risk from 1 in 72 to 1 in 10. you can see why acute infection accounts for a huge number of HIV transmissions.
this leads into your second question. it’s less risky to have sex with an HIV+ person with an undetectable viral load (not just any diagnosed HIV+ person) than with someone who doesn’t know their status. this is because people with undetectable viral loads don’t transmit HIV — there’s never been a documented case, and scientists have tried very hard to find one.
but it’s also because there are lots of people who don’t know they’re HIV+ — for example, an estimated 44% of HIV+ youth ages 13–24 don’t know it — and people who don’t know they’re HIV+ have the highest viral loads. after all, if you don’t know you’re HIV+, you can’t get on treatment and reduce your viral load. and most worryingly, people in the acute infection stage almost never know they’re HIV+. so if you assume your partner is negative, you could actually be facing a very high risk. and to make matters worse, people who assume their partners are HIV- are less likely to use condoms, PrEP, or other precautions.
this is why it’s so important that we have honest and open communication about HIV. instead of assuming you’re negative, get tested regularly. instead of assuming your partner is negative, ask them non-judgmentally about their last test. learn about the risks and your options for reducing them. advocate for universal access to quality education and medical care. and share what you’re learning about HIV with your community to increase knowledge, reduce HIV stigma, and move toward a future where AIDS really is history.
whew! that got long, but i hope i helped answer your questions.
