Temporal Trends in the Swedish HIV-1 Epidemic: Increase in Non-B Subtypes and Recombinant Forms over Three Decades

Abstract

BackgroundHIV-1 subtype B (HIV-1B) still dominates in resource-rich countries but increased migration contributes to changes in the global subtype distribution. Also, spread of non-B subtypes within such countries occurs. The trend of the subtype distribution from the beginning of the epidemic in the country has earlier not been reported in detail. Thus the primary objective of this study is to describe the temporal trend of the subtype distribution from the beginning of the HIV-1 epidemic in Sweden over three decades.MethodsHIV-1 pol sequences from patients (n = 3967) diagnosed in Sweden 1983– 2012, corresponding to >40% of patients ever diagnosed, were re-subtyped using several automated bioinformatics tools. The temporal trends of subtypes and recombinants during three decades were described by a multinomial logistic regression model.ResultsAll eleven group M HIV-1 subtypes and sub-subtypes (78%), 17 circulating recombinant forms (CRFs) (19%) and 32 unique recombinants forms (URF) (3%) were identified. When all patients were analysed, there was an increase of newly diagnosed HIV-1C (RR, 95%CI: 1.10, 1.06–1.14), recombinants (1.20, 1.17–1.24) and other pure subtypes (1.11, 1.07–1.16) over time compared to HIV-1B. The same pattern was found when all patients infected in Sweden (n = 1165) were analysed. Also, for MSM patients infected in Sweden (n = 921), recombinant forms and other pure subtypes increased.SignificanceSweden exhibits one of the most diverse subtype epidemics outside Africa. The increase of non-B subtypes is due to migration and to a spread among heterosexually infected patients and MSM within the country. This viral heterogeneity may become a hotspot for development of more diverse and complex recombinant forms if the epidemics converge.

Virological failure in patients with HIV-1 subtype C receiving antiretroviral therapy: an analysis of a prospective national cohort in Sweden

“…Patients are recruited from 30 infectious disease clinics across Sweden. 11 As of Jan 14, 2015, 10 010 patients were registered in the cohort. Of these, 8117 (81%) patients had been initiated on ART.…”

“…We also used molecular modelling and binding simulations to investigate the mechanisms of differential response by HIV subtypes. Most patients with HIV-1C in the cohort are from LMICs, 11 and our study provides insights into the potential factors for virological failure in HIV-1C-dominated epidemics in LMICs.…”

Molecular epidemiology of HIV-1 infection in Europe: An overview

“…In Sweden CRF01_AE strains circulating among PWID were introduced from Finland ( Skar et al, 2011). The rest of non-B strains including all major subtypes and many different recombinants were introduced from different African regions (subtype C, CRF02_AG), South Eastern Asia (CRF01_AE), but also from Eastern Europe (CRF06_cpx) (Neogi et al, 2014). For Denmark the origin of non-B subtypes has not been described in detail.…”

Novel tetra-peptide insertion in Gag-p6 ALIX-binding motif in HIV-1 subtype C associated with protease inhibitor failure in Indian patients

“…Primary and acquired drug resistance mutations (DRMs) were evaluated using World Health Organisation mutations list 2009 [16] and International AIDS Society list 2013[17] respectively. HIV-1 subtyping was performed as described recently using three automated bioinformatics tools [18]. Multiple-template homology models of the p6-ALIX complex were built in MODELLER 9v12 [19] using crystal structure of human ALIX/AIP1 in complex with a peptide fragment of the SIVmac239 and HIV-1 Gag-p6 proteins (PDB codes 2XS1 and 2R02) [20, 21].…”