In 2011, Timothy Brown became the first person cured of the disease in Berlin. Now, less than ten years later, a man from London has become the second person to have ever been cured of HIV.

HIV specifically targets CD4 cells, which are the body’s defenders against infection, since they use them to make copies of themselves. HIV can only spread by replicating and making copies of itself and killing the CD4 cells. The loss and deprivation of these cells are what make the illness severe. 

Brown was not cured by the HIV drugs he was taking or by any vaccine or shot, but by a stem cell treatment, which doctors say was very lucky. The lucky man following Brown is a London native named Adam Castillejo. 

Castillejo was getting a stem cell treatment for his cancer when his HIV was cured. The donors of those stem cells have a very rare gene that gives them protection to HIV. This incident is sporadic and does not mean much as of right now, unless in the future there is a way to get more stem cell donors, that are immune to HIV, to give them a stem cell treatment. However, this would be very limited, considering the immunity is rare. Hopefully, at some point, those cells might be able to be duplicated.