When do HIV-positive people have a legal obligation to disclose their HIV status to sexual partners?
Since 1998, at least 130 people have been charged with failing to disclose their HIV status before having sex. The legal test for conviction
asks whether there was a “significant risk” of HIV transmission.
Lower courts have wrestled with that test when condoms are used, since condoms can greatly reduce the risk of HIV transmission. Similarly, the use of antiretroviral drugs can lower an HIV-positive person's viral load, which also reduces the risk of transmission. The court will likely rule on whether condom use or low viral load is a bar to prosecution.
Both cases touch on these issues. In Mabior, an HIV-positive man had sex with multiple women without disclosing his status. He had a low viral load and used condoms on some occasions. In the other case, known as DC, a woman didn't tell her partner her HIV status before the first time they had sex. She told him later, and the relationship continued for several years. No partner in either case became HIV-positive as a result.