A long legacy in global health: Former President Jimmy Carter has worked to end neglected diseases since 1982. Here he sits with former South African President Nelson Mandela at a ceremony in Soweto, celebrating a new AIDS project in 2002. AFP/Getty Images hide caption

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A celebration erupts in the streets of the Massessehbeh village on Friday, after President Ernest Bai Koroma officially ended Sierra Leone's largest remaining Ebola quarantine. Sunday Alamba/AP hide caption

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Nurse Issa French with his wife Anita, who's holding a copy of Time magazine's issue devoted to front-line workers. He's earned that title, treating more than 420 Ebola patients. Amy Maxmen for NPR hide caption

itoggle caption Amy Maxmen for NPR

The PharmaChk is a bit like a litmus test for drugs: You pop in a pill at one end, and in 15 minutes, a number appears on a screen telling you the drug's potency. Mahafreen H. Mistry/NPR hide caption

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A child is vaccinated in Makadara Health Clinic, Nairobi, Kenya. Greg Warner/NPR hide caption

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Ricardo "Cobe" Williams, wearing the cap, served time for attempted murder before joining CeaseFire as a "violence interrupter." Above, he talks with Lil Mikey in a scene from the documentary The Interrupters. Lil Mikey, who'd also been in prison, went on to become an outreach worker with the organization. Aaron Wickenden/Courtesy of Kartemquin Films hide caption

itoggle caption Aaron Wickenden/Courtesy of Kartemquin Films

A woman receives the rVSV-ZEBOV Ebola vaccine at a clinical trial in Conakry, Guinea. The vaccine appears effective after only one shot. Cellou Binani/AFP/Getty Images hide caption

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The Ebola vaccine from a trial in Guinea needs to be kept at a temperature of minus 60 degrees Celsius, the World Health Organization says. Storage devices use jet fuel to keep the right temperature for up to five days in the field. Sean Hawkey/Sean Hawkey hide caption

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The bar chart tells all: That's how eighth-graders at Bakgatle Community Junior Secondary School in Botswana can compare the HIV infection rate of older men and of teenage boys. Don Boroughs for NPR hide caption

itoggle caption Don Boroughs for NPR