Almost half of the new HIV diagnoses were among people originating from outside the reporting country (migrants) in Europe the last few years. We aimed to trace the geographic origin of HIV-1 CRF02_AG infections, the most prevalent non-B clade in France, for migrants in Paris, using molecular epidemiology methods.
We studied the first available pol gene sequence for all patients infected with HIV-1 CRF02_AG (N=2,146) diagnosed in two large Parisian University hospitals. HIV-1 subtyping was carried out using automated subtyping tools (COMET, REGA). We analyzed phylogenetically the CRF02_AG sequences from migrants (N=567) along with all the available CRF02_AG sequences from non-migrant patients (N=1,579). We also included all publicly available CRF02_AG sequences (N=3,476), and unpublished CRF02_AG sequences from Spain, Italy and Greece (N=1193), as references. Local transmission networks (LTNs) were phylogenetic clusters including sequences from France at proportions >70%, receiving bootstrap value >70% or SH-support >0.8. Phylogenetic trees were estimated by the maximum likelihood method (RAxML, FastTree). The origin of HIV-transmissions was traced by phylogeographic analysis using the criterion of parsimony (Mesquite).
Phylogenetic analysis revealed that 198 (34.9%) sequences from migrants clustered within LTNs. The distribution of transmission risk group in migrants infected with CRF02_AG strains was: Heterosexuals (N=447; 78.8%), MSM (N=37; 6.5%), Others/Unknowns (N=83; 14.7%). The proportion of migrant MSM within CRF02_AG LTNs was significantly higher (83.8%) than the corresponding proportion of heterosexuals (31.5%) (p<0.001). Phylogeographic analysis showed that 29.3% of the CRF02_AG HIV-transmissions within migrants occurred in France. Multivariate analysis showed that parameters associated with clustering within the large LTNs (≥10 sequences) were MSM risk group (MSM vs heterosexuals OR: 10.3, 95% CI: 6.5-16.5) and French origin (non-migrants vs migrants OR: 2.4, 95% CI: 1.5-3.9).
We found that 29.3% of CRF02_AG HIV-transmissions within migrants originated in Paris. Transmissions among migrants within LTNs were associated with MSM risk group. Moreover, transmissions within large clusters are more frequent among MSM and non-migrants. This is one of the few molecular studies showing that even for CRF02_AG, which is prevalent in Sub-Saharan Africa, a large proportion of transmissions among migrants occur in Paris.