Approximately 38 million people are infected with HIV worldwide, about 1.1 million people in the United States. Currently, people with HIV take antiretroviral therapy (ART), which can suppress HIV to undetectable levels in blood, but the virus persists throughout the body in latently infected resting CD4+ T cells. The immune system cannot recognize these cells and no current therapies can eliminate them. When ART is stopped, viral loads spike in blood. This is why people with HIV must take ART continuously, and this latent reservoir is considered the greatest obstacle to a cure.