The Ad26.Mos4.HIV vaccine – which uses the same adenoviral technology as J&J’s COVID-19 vaccine and targets four HIV antigens – was shown to be safe in the late-stage Mosaico trial, but was not effective compared to placebo at preventing HIV infection.
The study, also known as HPX3002 and HVTN706, started in 2019 amid great expectations for the vaccine, and enrolled 3,900 men who have sex with men (MSM) and transgender individuals considered to be at elevated risk of HIV in the Americas and Europe.