Joep Lange

In June this year, three months before turning 60, Joep Lange was on a plane, chatting with a colleague about his work. Lange had spent most of his adult life on HIV/AIDS—as a pioneer researcher helping to understand the basic pathology of the virus, as a caring doctor, and as a determined advocate for HIV/AIDS patients around the world, especially in Africa.

But after three decades of hard work, Lange knew that the battle against HIV/AIDS had not been won—and was not even close to being won. There was still much to be done, still millions and millions of suffering people he wanted to help. Lange would need more time. Lange’s colleague on the flight, Jacques van der Gaag, professor of development economics at the University of Amsterdam, noted that it is now normal to continue working beyond the traditional retirement age of 65. He told Lange: “You still have at least 10 more productive years in you.”

Lange replied: “But that is not enough.”

On 17 July Lange boarded a plane in Amsterdam to travel as a delegate to the 20th International AIDS Conference in Melbourne. With him on board was his partner, Jacqueline van Tongeren, and at least four other delegates to the conference. In an unimaginable horror, the plane—Malaysia Airlines flight MH17—crashed in Ukraine after apparently being shot down. All 283 passengers and 15 crew …