Screening will take place during the 6 weeks prior to randomisation. Eligible participants will be enrolled at week 0 and randomised to MVA HIV-B vaccine followed by vedolizumab, vedolizumab + placebo vaccine, or placebo vaccine + placebo infusions.
Participants will be randomised at each centre through web-based randomisation after entering the eligibility criteria. There will be two strata: one for those who started treatment during primary infection, and one for those who started treatment during chronic infection.
69 eligible individuals from collaborating European Countries will be enrolled, aiming for approximately half who started cART in primary infection and half who started in chronic infection. Participants continue from the screening visit (up to 6 weeks before enrolment) to the last visit, a maximum of 60 weeks (around 14 months), although follow-up will continue through to the time when virus is fully suppressed.
Treatment will be interrupted at week 18 and resumed when the viral load is confirmed to have rebounded to ≥100,000 copies/ml, or the CD4 falls to ≤350 cells/mm3, confirmed, or there is evidence of disease progression, or they have completed 24 weeks of treatment interruption.