Differential patterns of postmigration HIV-1 infection acquisition among Portuguese immigrants of different geographical origins

OBJECTIVE: To investigate the dynamics of phylogenetic transmission clusters involving immigrants of Portuguese Speaking Countries living in Portugal. DESIGN/METHODS: We included genomic sequences, sociodemographic and clinical data from 772 HIV migrants followed in Portugal between 2001 and 2017. To reconstruct HIV-1 transmission clusters, we applied phylogenetic inference from 16 454 patients: 772 migrants, 2973 Portuguese and 12 709 global controls linked to demographic and clinical data. Transmission clusters were defined using: clusters with SH greater than 90% (phylogenetic support), genetic distance less than 3.5% and clusters that included greater than 66% of patients from one specific geographic origin compared with the total of sequences within the cluster. Logistic regression was performed to assess factors associated with clustering. RESULTS: Three hundred and six (39.6%) of migrants were included in transmission clusters. This proportion differed substantially by region of origin [Brazil 54% vs. Portuguese Speaking African Countries (PALOPs) 36%, P