You are likely familiar with PrEP: pre-exposure prophylaxis, an anti-retroviral drug that you can take a daily dose of if you’re at higher risk for getting HIV, like a birth control pill but to prevent HIV infection instead of pregnancies.
It’s usually prescribed to people who are at high risk for HIV infection — for instance, if you have a sexual partner who is HIV positive, or if you have a lot of casual sex partners, especially if you’re a man having lots of casual sex with other men. Combined with condoms, PrEP is fantastically effective. Used without condoms, it is still fantastically effective, which has driven most of the controversy — because, although it prevents HIV infection, it doesn’t do anything to prevent all the other STDs out there, including the antibiotic-resistant strain of gonorrhea that’s now circulating. That said: if you’re having a lot of casual sex, especially if it’s anal sex, you should totally take PrEP because “protected against HIV but not gonorrhea, syphilis, or chlamydia” beats the hell out of “protected against none of the above.”
The biggest downside of PrEP is that it’s expensive to take every day. (About $10K/year, although if you’re willing to order from an online pharmacy that is shipping you pills from Turkey or India, you can get a year’s supply for under $1000. Note: this is technically illegal.) Some people apparently also have some sort of psychological resistance to taking a pill every day. Both of these problems can be mitigated by using PrEP intermittently, and here we come to the point of the new study.
Unlike birth control pills, PrEP seems to still be quite effective if you’re taking it just when you have sex, but it helps if you can predict when you’re going to have sex. (Accurately!) So a new study was just released in the U.S. on whether men who are having regular sex with other men are any good at guessing whether they’re going to have sex the next day.
The answer was sort of amusing: men are really good at knowing when they are absolutely not getting any. The men who said that there was a zero to 5% chance of having sex the next day had, in fact, a 4% chance of having sex the next day. And if they said they absolutely were not going to be having sex, none of them did.
If they were feeling more optimistic, however, they were right about half the time. Men who said there was a 100% chance of sex the following day had it 58% of the time. Men who said there was a 50% chance had it 20% of the time; if a 20% chance, they had it 10% of the time.
My teenage daughter peered over my shoulder as I was reading the study and asked if anyone had checked to see whether straight men had similar results. Short answer: no one’s doing a study on it. My unscientific guess: straight men would show less optimism, but similar accuracy.
I think it’s worth noting here that when the researchers said “sex,” what they meant was very specific: anal intercourse with a casual partner. According to my go-to source on gay sex (Dan Savage, duh), there’s no default for same-sex encounters. You have to have a conversation about what you’re into. So even if casual anal intercourse would be your first choice, you might find yourself in bed with a guy who prefers something else. And, in fact, you might have what you consider to be sex and I consider to be sex and Dan Savage sure as heck considers to be sex, but is not “sex” by the researchers’ criteria. So possibly your tracking diary said you’d predicted a 100% chance of sex, and in fact you were totally right — but it wasn’t anal, so it’s going down in the record-keeping software that night as a “nope.”
Anyway, the researchers concluded that it would be pretty safe to tell men that they could skip a dose if they were positive they weren’t having sex the next day.
The bottom line here, by the way: if you’re at elevated risk of HIV, but can’t afford daily Truvada, you should totally get some for special occasions. Can’t hurt, might help. The only real downside would be if you kept it around for special occasions, and that made you more likely to have unsafe sex on those occasions when you hadn’t taken the Truvada because you’ve been lulled into a false sense of security by the knowledge that you had Truvada in your medicine cabinet. Could this happen? Given the straight couples I know who got knocked up because their condoms never made it out of the nightstand — maybe. Truvada: not a license to be a complete idiot.
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