In recent years, researchers have firmly established that people living with HIV can best protect their health by starting antiretroviral (ARV) medications as early as possible in the course of their infection. From then on out, it’s important to adhere well to the daily drug regimen indefinitely. Even structured breaks from ARVs—the so-called drug holidays that were once in vogue—were proved harmful in the mid-2000s.

So why are the investigators behind so many studies in the HIV research field these days experimenting with taking people off their ARVs for periods of time?

They do it in the name of finding a cure. Or if not a cure—meaning total eradication of HIV from the body—then some form of viral remission or post-treatment control of the virus without daily ARV treatment. Such outcomes may include a scenario in which HIV is still clearly present but the immune system suppresses the virus well on its own. Or perhaps the population of virus in the body has been so decimated it fails to bounce back, at least for an extended period. (In this article, the umbrella term “HIV cure” applies to research into prompting any such outcomes.)

Today’s HIV cure studies run a very wide gamut in their approaches. Some seek to shrink the size of the reservoir through a process known as “kick and kill,” waking upunreplicating cells and then attempting to destroy them. Others give individuals some sort of gene-based or antibody-based treatment intended to prime their body to better control the virus without daily drugs. There are also studies of people, both those who contracted HIV as adults and children born with the virus, who were treated very early in the course of their infection and who may as a result have a very small, or possibly even nonexistent, reservoir. These early-treated individuals may be able to go off their ARVs and spend considerable time—sometimes many years, as researchers have seen thus far in a handful of cases—without the reservoir prompting the viral load to rebound.