A very small percentage of people with HIV-1, known as ‘post-treatment controllers’ (PTCs), are able to control their infection after interrupting all antiretroviral therapy. Understanding the fundamental mechanisms that govern their immune response is essential in order to develop HIV-1 vaccines, novel therapeutic strategies to achieve remission, or both. A recent study investigated the humoral immune response — also known as antibody-mediated immunity — in some PTCs in whom transient episodes of viral activity were observed. The researchers have shown their humoral immune response to be both effective and robust, which could help to control the infection in the absence of treatment.