More than 30,000 people are diagnosed with HIV every year in this country. But this is not a problem for any single community. Almost a quarter of Americans are infected through intimate heterosexual contact. Medication to prevent HIV infection through sexual contact, known as "PrEP," is 99% effective when taken as prescribed. But as CBS News medical contributor and editor at large for Public Health at KFF Dr. Celine Gounder reports, not everyone at risk for HIV is getting the message.