Heather, a woman in her mid to late 50s, smiles at her phone-a new match on a dating app. They arrange a date.

Getting ready, she tosses her birth control pills in the trash. "So glad I don't need birth control anymore," she says.

The date goes well. Later that week, she tells her friend, "Dating at 56 has been an adventure." Her friend, a nurse, warns her: STIs have doubled in people aged 50 and older in the last decade. Menopause also increases vulnerability.

Her friend advises, "Maybe you should get an HIV test. Just to be safe." Heather hesitates, then agrees. The next day, she arrives at a testing clinic, thinking, "Positive or negative, at least I'll know."