Epidemiology of non-B clade forms of HIV-1 in men who have sex with men in the UK

Department of HIV, Guys and St Thomas' NHS Trust/ Kings College London, St Thomas' Hospital, London, UK.
AIDS (London, England) (Impact Factor: 5.55). 09/2010; 24(15):2397-401. DOI: 10.1097/QAD.0b013e32833cbb5b
Source: PubMed


To describe the frequency and risk factors of non-B HIV-1 subtypes in men who have sex with men (MSM) in the UK.
Observational study.
MSM diagnosed with HIV-1 infection from 1980-2007, with HIV genotype held in the UK HIV Drug Resistance Database were identified. Protease and reverse transcriptase sequences were collected and viral clade determined using the REGA algorithm. Associations between demographic variables and subtype were analysed using logistic regression.
The prevalence of non-B HIV-1 infection amongst MSM in the UK was 5.4% (437/8058). In the UK this increased with year of diagnosis from pre1996 to 2002, and has subsequently remained relatively stable at around 7-9% after 2002, with a recent increase in 2007 to 13%. Multivariate analysis showed that acquisition of non-B HIV-1 infection was independently associated with later year of HIV diagnosis (P < 0.001), black ethnicity (P < 0.001) and non-European country of birth (P = 0.01). Age was also associated with subtype with individuals aged 25-39 years being less likely to have non-B virus than those aged less than 25 years (P = 0.01). Restricting the analysis to white men born in the UK, the association between subtype and year of diagnosis remained statistically significant (P < 0.001), as did the association with age (P < 0.001).
The number of MSM in the UK infected with non-B clade HIV-1 is increasing, suggesting that the sociodemographic boundaries between HIV-1 viral subtypes globally are diminishing. Should viral subtypes be relevant to clinical disease progression or vaccine design, the changing pattern of distribution will need to be taken into account.

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    • "These patients were mostly from Greece (n=53), but also from Cyprus (n=3), Portugal (n=2), Spain (n=1), the Netherlands (n=1) and Ireland (n=1). The increase in proportion of subtypes A1 and C has also been described in the MSM population of the United Kingdom [27]. Subtype G was significantly less prevalent in MSM (0.32%) than in IDUs (10.05%) and heterosexuals (7.20%), while subtypes C, CRF02_AG and CRF01_AE were significantly more prevalent in heterosexuals (15.7%, 7.41% and 9.16% respectively) than in IDUs (1.44%, 3.35% and 0.48% respectively) and MSM(0.48%, "
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    ABSTRACT: Background: Understanding HIV-1 subtype distribution and epidemiology can assist preventive measures and clinical decisions. Sequence variation may affect antiviral drug resistance development, disease progression, evolutionary rates and transmission routes. Results: We investigated the subtype distribution of HIV-1 in Europe and Israel in a representative sample of patients diagnosed between 2002 and 2005 and related it to the demographic data available. 2793 PRO-RT sequences were subtyped either with the REGA Subtyping tool or by a manual procedure that included phylogenetic tree and recombination analysis. The most prevalent subtypes/CRFs in our dataset were subtype B (66.1%), followed by sub-subtype A1 (6.9%), subtype C (6.8%) and CRF02_AG (4.7%). Substantial differences in the proportion of new diagnoses with distinct subtypes were found between European countries: the lowest proportion of subtype B was found in Israel (27.9%) and Portugal (39.2%), while the highest was observed in Poland (96.2%) and Slovenia (93.6%). Other subtypes were significantly more diagnosed in immigrant populations. Subtype B was significantly more diagnosed in men than in women and in MSM > IDUs > heterosexuals. Furthermore, the subtype distribution according to continent of origin of the patients suggests they acquired their infection there or in Europe from compatriots. Conclusions: The association of subtype with demographic parameters suggests highly compartmentalized epidemics, determined by social and behavioural characteristics of the patients.
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    • "Non-B subtypes were present but rare in the UK until 1995, after which a substantial increase in immigration from southern Africa, particularly Zimbabwe, led to a dramatic rise in subtypes C and A (Parry et al. 2001). By 2005, the prevalence of non-B clades taken together equaled the B clade, and recently, in both France and the United Kingdom, there has been noticeable, and nonreciprocal, crossover of non-B clades into MSM (de Oliveira et al. 2010; Fox et al. 2010). Similarly, Swiss investigators have confirmed changes in B clade viral transmission over time (Kouyos RD et al. 2010). "
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    ABSTRACT: The HIV epidemic in higher-income nations is driven by receptive anal intercourse, injection drug use through needle/syringe sharing, and, less efficiently, vaginal intercourse. Alcohol and noninjecting drug use increase sexual HIV vulnerability. Appropriate diagnostic screening has nearly eliminated blood/blood product-related transmissions and, with antiretroviral therapy, has reduced mother-to-child transmission radically. Affected subgroups have changed over time (e.g., increasing numbers of Black and minority ethnic men who have sex with men). Molecular phylogenetic approaches have established historical links between HIV strains from central Africa to those in the United States and thence to Europe. However, Europe did not just receive virus from the United States, as it was also imported from Africa directly. Initial introductions led to epidemics in different risk groups in Western Europe distinguished by viral clades/sequences, and likewise, more recent explosive epidemics linked to injection drug use in Eastern Europe are associated with specific strains. Recent developments in phylodynamic approaches have made it possible to obtain estimates of sequence evolution rates and network parameters for epidemics.
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