Therapeutic HIV vaccines could one day be part of a combination strategy for achieving a functional cure for HIV. Spanish scientists tested a series of HTI (HIVACAT T-cell immunogen) vaccines designed to help T cells recognize parts of the virus that trigger immune responses in people who naturally control HIV. One delivers HIV DNA directly, one uses a modified vaccinia Ankara viral vector and one uses a chimpanzee adenovirus vector similar to the one used for the AstraZeneca-Oxford COVID-19 vaccine. In this early study, 45 people who started antiretroviral therapy soon after infection and had an undetectable viral load received up to eight vaccine or placebo injections; they could then opt for a treatment interruption. Viral load rebounded in all cases, but the new viral setpoint was lower in the vaccine group. In a subset of 32 participants, eight vaccine recipients (40%) and one placebo recipient (8%) were able to remain off antiretrovirals for nearly six months. Five vaccine recipients and one placebo recipient maintained a viral load below 2,000.