Fig 1. PRISMA flow diagram.

^a Sampled studies include those characterized as (1) conducted in Africa, and ‘thick’, or (2) ‘thin’ and belonging to specific population group of interest: A ‘thick’ study was defined according to the depth of analysis which included the following features: 1) the extent to which the authors transformed/analysed their findings, 2) insight into perspectives was demonstrated, 3) richness and complexity had been portrayed, and 4) there was theoretical or conceptual development. “Thin” studies were all other studies not classified as ‘thick’. Specific population of interest studies included those classified as thin but that evaluated perspectives which were of special interest for the review, including; provider perspectives, MSM populations, sex-worker populations; PWID populations; youth being transferred to new facilities; or conducted among refugee populations. ^bData saturation was reached.