After 30 years of immunology research, [Louis Picker] is on the verge of launching human trials for a vaccine that could stop AIDS, an epidemic that has become something of an afterthought decades after it began ravaging gay men in America. For many in the developed world, complacency has set in, largely thanks to a regimen of antiretroviral drugs that allow people with HIV to live long and healthy lives, and decades of failed attempts to develop a vaccine. In 1984, U.S. Secretary of Health and Human Services Margaret Heckler expressed hope ... that science might have a vaccine for HIV within two years. Instead, a decade passed, and by 1994, AIDS was the leading cause of death for Americans ages 25 to 44. Four vaccines have made it to human trials, but none made it to market. As Picker continued his research, scientists developed a series of antiretroviral drugs that slowly downgraded HIV to a chronic disease ... in the developed world. But globally, AIDS is still killing a lot of people, largely because most of those infected in poorer countries don't have access to the drugs. According to the World Health Organization, 1.1 million people died from AIDS in 2015. In the U.S., 50,000 new cases of HIV are reported every year. Worldwide, the number is 2 million. Every time news reports come out about Picker's research, he fields a series of phone calls from HIV-infected patients, their friends and their family. Can I be in your trial?" people ask him. "Please, can you save my son?"