Adam Castillejo was living with HIV when he was treated for Hodgkin lymphoma, a blood cancer. In May 2016, like Timothy Ray Brown before him, described in Berlin Patient, he received a stem cell transplant from a donor with a mutation in the CCR5 protein. He was far less ill after his treatment than Brown had been, and he stopped taking anti HIV drugs in September 2017.

In March 2019 his doctors, led by Ravindra Gupta of University College London, reported that the man then known only as the London patient was in sustained remission from HIV, the second person ever documented in that state. Gupta called the case a game changer: after the Berlin patient, he said, everyone believed you needed nearly to die to cure HIV, and now perhaps you did not. His doctors publicly described it as long term remission, while experts in interviews called it a cure.

In March 2020 Castillejo revealed his identity. He said he saw himself as…