As with other sexual practices, people without sound knowledge about the sexual risks involved are susceptible to STIs. Because of the view that anal sex is not "real sex" and therefore does not result in virginity loss, or pregnancy, teenagers and other young people may consider vaginal intercourse riskier than anal intercourse and believe that a STI can only result from vaginal intercourse. It may be because of these views that condom use with anal sex is often reported to be low and inconsistent across all groups in various countries.
For people with HIV, HIV medicine (called antiretroviral therapy or ART) can reduce the amount of virus in the blood and body fluids to very low levels, if taken as prescribed. This is called viral suppression—usually defined as having less than 200 copies of HIV per milliliter of blood. HIV medicine can even make the viral load so low that a test can’t detect it. This is called an undetectable viral load. People who take HIV medicine as prescribed and get and stay virally suppressed or undetectable can stay healthy for many years, and they have effectively no risk of transmitting HIV to an HIV-negative partner through sex. Only condoms can help protect against some other STDs.
Reduce your risk of cutting or scratching your partner by trimming your nails. Long nails might tear the thin, delicate tissue of the anus, which could lead to bleeding. It also increases the risk of spreading bacteria that could cause infections. Be sure to wash your hands well and scrub under your nails after anal sex, too, especially before inserting them into the vagina or mouth.