In the world, 35 million people are living with HIV or AIDS. Most take a myriad of drugs to suppress the disease from wreaking havoc on their immune system.

Loreen Willenberg is one of those 35 million, but in the 23 years since she was diagnosed, she takes no drugs, has no symptoms, and has never been sick.

“In a clinical sense, I’m not progressing towards AIDS,” she said. “I’m not progressing towards the disease stage.”

Dr. Richard Pollard says she’s part of a small number of HIV patients—less than 1 percent—who have the virus, but can control its invasion of their bodies.