Recently, a fifth person was cured of HIV in Germany. According to research published in the journal “Nature Medicine” on Monday, the man was monitored for more than nine years after a stem cell transplant in 2013, and there is now “strong evidence” that he has been cured.

HIV, or human immunodeficiency virus, enters and destroys the cells of the immune system. Without treatment, the continued damage can lead to AIDS, or acquired immunodeficiency syndrome, where a person cannot fight even a small infection. ART (antiretroviral therapy) can stop HIV from multiplying and help an individual’s immune system get stronger. If those with HIV take the medication daily, they can decrease the viral load so that it is “undetectable” and not transmissible to sexual partners. However, HIV, when left untreated, can progress to AIDS.

With about 38.4 million people globally living with HIV, treatments have come a long way. Modern medication can keep the virus at bay, and studies looking into preventing HIV infection with a vaccine are also underway.

The remission of HIV, which is usually considered lifelong, comes after a team at University Hospital Düsseldorf destroyed the patient’s cancerous cells and replaced them with donor cells that lack CCR5, the receptor that HIV particles use to infect cells. In 2018, the patient went off ART and has remained free of HIV since. “It’s really a cure, and not just, you know, long-term remission,” said Dr. Bjorn-Erik Ole Jensen, who presented details of the case in a new publication in “Nature Medicine.” “It shows it’s not impossible — it’s just very difficult — to remove HIV from the body,” Dr. Bjorn-Erik Ole Jensen said.

Unfortunately, not everyone can get a stem cell transplant because it is a high-risk procedure that effectively replaces a person’s immune system and is typically only used to cure someone’s cancer. The primary goal is to cure someone’s cancer, but the procedure has also led to an HIV cure in a handful of cases.