On Sunday, NewsHour Weekend examines an ambitious new plan in San Francisco to completely end new HIV infections. About 50,000 people become infected with HIV every year in the United States and an estimated 13,700 still die from AIDS, even as improved treatments make the virus more manageable. While infections in San Francisco have been falling over the past eight years, they haven't gone away. And in a city where huge strides have been made in battling the epidemic that's killed tens of thousands of people, public health officials, doctors and activists are increasing their efforts to bring the number of new HIV infections down to zero. NewsHour's John Carlos Frey reports from San Francisco.