The documentary Back On Board follows the career of four-time Olympic champion Greg Louganis. HBO hide caption

toggle caption HBO

Transgender performers walk backstage during an event to mark World AIDS Day in 2013. A new WHO report demonstrates extremely rates of HIV infection among transgender women in 15 countries. Prakash Mathema/AFP/Getty Images hide caption

toggle caption Prakash Mathema/AFP/Getty Images

Nurse Brittany Combs of Scottsburg, Ind., delivers clean needles to a member of the needle exchange program. Users must have a membership ID card to exchange needles. Seth Herald for NPR hide caption

toggle caption Seth Herald for NPR

Volunteers search for needles and other drug paraphernalia along Church Street in Austin, Ind., in April. The region has recorded 142 new HIV cases since December, according to the state, in an outbreak tied to injected-opioid use. Seth Herald/Nurphoto/Corbis hide caption

toggle caption Seth Herald/Nurphoto/Corbis

Needle exchange programs, like this one in Portland, Maine, offer free, sterile syringes and needles to drug users. The programs save money and lives, health officials say, by curtailing the spread of bloodborne infections, such as hepatitis and HIV. Robert F. Bukaty/AP hide caption

toggle caption Robert F. Bukaty/AP

Truvada can dramatically reduce the risk of HIV infection when taken as a preventative medicine — if taken every day. Studies are underway to determine if young people are likely to take the pill consistently. Justin Sullivan/Getty Images hide caption

toggle caption Justin Sullivan/Getty Images

A December celebration launching a partnership between members of the Garifuna community and a doctor in New York. The collaboration is aimed at reducing the HIV infection rate among the Garifuna. Alexandra Starr/NPR hide caption

toggle caption Alexandra Starr/NPR

Augustine Goba (right) heads the laboratory at Kenema Government Hospital in Sierra Leone. He and colleagues analyzed the viral genetics in blood samples from 78 Ebola patients early in the epidemic. Stephen Gire/AP hide caption

toggle caption Stephen Gire/AP

David Adam is a writer and editor at the journal Nature and was a special correspondent at the Guardian, writing about science, medicine and the environment. Courtesy of Farrar, Straus and Giroux, LLC hide caption

toggle caption Courtesy of Farrar, Straus and Giroux, LLC

In Philadelphia, some drug users are selling clean needles from needle exchange programs on the street. Researchers say the black market isn't necessarily a bad thing. ImageZoo/Corbis hide caption

toggle caption ImageZoo/Corbis

NPR thanks our sponsors

Become an NPR sponsor