In parts of Africa, where the HIV rate is 36 percent, researchers tested out a simple idea: They made access to care easier for people living with a chronic condition.

In a nearly three-year study in South Africa and Uganda, researchers used mobile vans in five communities to dispense care and treatment to 1,315 people living with HIV and not on antiretroviral treatment.

The randomized controlled trial, conducted between May 2016 and March 2019, found that viral suppression was 74 percent, compared to 63 percent for those seen in a clinic.

In the mid-2000s, researchers conducted a clinical trial in Ethiopia to see what it would take to eliminate trachoma, a disease caused by the bacterium Chlamydia trachomatis and the most common cause of blindness from infection worldwide. They randomly gave one- to 10-year-old kids either the antibiotic azithromycin to clear and prevent infection or delayed their treatment until after the trial ended.