Arm B (B 1 B 2 B 3): will start with 7 days Raltegravir 400mg /lamivudine 150mg bd and then have a one month wash out before then starting 7 days Raltegravir 400mg bd. This will remove sequential selection bias. All individuals will receive tissue sampling at baseline for ex vivo analysis to ensure biopsies are infectable on challenge assays. Sampling from women will avoid menstruation and if possible focus on the luteal phase of the menstrual cycle. Individuals will receive another set of tissue sampling during and after ART in phase 1, have a 4 week wash out period and then have another set of sampling during and after ART in phase 2. Individuals will therefore have 5 sets of sampling during the trial.