Jennifer Vaughan of Watsonville, Calif., vividly remembers the moment she learned she could not transmit the virus to her boyfriend. The mother of three tested positive in February 2016 after she became critically ill with what was finally determined to be AIDS. HIV was not among the possibilities she or her doctors considered, until a blood test revealed the virus. She thinks she was infected by a previous boyfriend with a history of intravenous drug use.

Vaughan attended a speech Richman gave and was talking with him in a parking lot outside a Starbucks.

“I’ll never forget him saying those words, ‘You can’t transmit the virus if you’re undetectable,’ ” the 47-year-old substitute teacher recalled. “And I said, ‘Wait, what?’

“It was like the sky opened. Are you kidding? There’s, like, zero risk? I don’t feel like I’m a threat anymore. I don’t feel like I’m dirty. I don’t feel like I’m a dangerous person.”