For decades, this was actually true.
“There’s a reason they called it an epidemic,” says Dr. Malvestutto. “But we’ve come a very long way since the 1980s in terms of learning how to control transmission.”
But with new medical advances like antiretrovirals, which lower the level of HIV in your body—known as the viral load—it’s simply not the case anymore. In fact, there’s a catchy mnemonic in the infectious disease world now: U=U. If your HIV is undetectable—meaning the viral load is low enough so it doesn’t show up on blood tests—then it’s very unlikely to be transmitted.
“There are numerous studies to support this, and the CDC supports this, because the data is consistent,” Dr. Malvestutto says. “So, although we still encourage condom use to prevent other STDs, the risk of HIV is just not there if the condom breaks.”
Still, it’s not a complete certainty: The CDC says it’s still possible to transmit HIV to partner if you have an undetectable viral load, since the tests for it only measure the load in blood, not other fluids like semen. It’s also possible viral load can fluctuate in between testing.