“I realized, what I call ‘risk’ is what a 17-, 18-year-old calls dating, someone else calls it their job, they’re going to work,” Mena said. He points to a study he conducted over three years with people ages 18 to 25. Of those who tested positive for HIV, 90 percent said they weren’t at risk in the 12 months before the positive test. Further, Mena said, women answered, “I don’t know,” when he asked how they contracted HIV.