SARS-CoV-2 clade dynamics and their associations with hospitalisations during the first two years of the COVID-19 pandemic.

BACKGROUND: The COVID-19 pandemic was characterised by rapid waves of disease, carried by the emergence of new and more infectious SARS-CoV-2 virus variants. How the pandemic unfolded in various locations during its first two years has yet to be sufficiently covered. To this end, here we are looking at the circulating SARS-CoV-2 variants, their diversity, and hospitalisation rates in Estonia in the period from March 2000 to March 2022. METHODS: We sequenced a total of 27,550 SARS-CoV-2 samples in Estonia between March 2020 and March 2022. High-quality sequences were genotyped and assigned to Nextstrain clades and Pango lineages. We used regression analysis to determine the dynamics of lineage diversity and the probability of clade-specific hospitalisation stratified by age and sex. RESULTS: We successfully sequenced a total of 25,375 SARS-CoV-2 genomes (or 92%), identifying 19 Nextstrain clades and 199 Pango lineages. In 2020 the most prevalent clades were 20B and 20A. The various subsequent waves of infection were driven by 20I (Alpha), 21J (Delta) and Omicron clades 21K and 21L. Lineage diversity via the Shannon index was at its highest during the Delta wave. About 3% of sequenced SARS-CoV-2 samples came from hospitalised individuals. Hospitalisation increased markedly with age in the over-forties, and was negligible in the under-forties. Vaccination decreased the odds of hospitalisation in over-forties. The effect of vaccination on hospitalisation rates was strongly dependent upon age but was clade-independent. People who were infected with Omicron clades had a lower hospitalisation likelihood in age groups of forty and over than was the case with pre-Omicron clades regardless of vaccination status. CONCLUSIONS: COVID-19 disease waves in Estonia were driven by the Alpha, Delta, and Omicron clades. Omicron clades were associated with a substantially lower hospitalisation probability than pre-Omicron clades. The protective effect of vaccination in reducing hospitalisation likelihood was independent of the involved clade.

No transmitted drug resistance to HIV integrase strand-transfer inhibitors after their scale-up in Estonia in 2017.

OBJECTIVES: In Eastern Europe, HIV-1 transmitted drug resistance (TDR) data, especially in the integrase (IN) region, are limited. In Estonia, INSTI (integrase strand transfer inhibitors) TDR has been studied only prior to the INSTI scale-up in late 2010s. The current study aimed to determine the levels of protease (PR), reverse transcriptase (RT) and IN surveillance drug resistance mutations (SDRMs) among newly diagnosed patients in Estonia in 2017. METHODS: The study included 216 newly diagnosed HIV-1 individuals from 1 January until 31 December 2017 in Estonia. Demographic and clinical data were obtained from the Estonian Health Board, the Estonian HIV Cohort Study (E-HIV) and clinical laboratories' databases. The PR-RT and IN regions were sequenced and analysed for SDRMs and subtype determination. RESULTS: Seventy-one percent (151/213) of available HIV-positive samples were successfully sequenced. The overall level of TDR was 7.9% (12/151; 95% CI 4.4%-13.8%); no dual or triple class resistance was detected. No major INSTI mutations were found. The distribution of SDRMs for NNRTI, NRTI and PI was 5.9% (9/151), 1.3% (2/151) and 0.7% (1/151), respectively. The predominant NNRTI mutation was K103N. CRF06_cpx was the predominant variant (59%) in the Estonian HIV-1 population, followed by subtype A (9%) and subtype B (8%). CONCLUSION: Although no major INSTI mutations were found, close monitoring of INSTI SDRMs is needed considering the extensive use of the first- and second-generation INSTIs. PR-RT TDR is slowly rising in Estonia, indicating the need for continuous surveillance in the future. Low genetic barrier NNRTIs should be avoided in the treatment regimens.

Norovirus strains among children aged 0-18 years hospitalized with acute gastroenteritis in Estonia 2015-2016.

Norovirus (NoV) is the leading cause of acute gastroenteritis (AGE) in many countries that have introduced universal rotavirus mass vaccination. This is the first study to report data on NoV strains in Estonia. We recruited 2249 children aged 0-18 years hospitalized for AGE in Estonian hospitals from February 1, 2015 to August 31, 2016. Norovirus gastroenteritis (NoVGE) was diagnosed in 14.5% (n = 325) cases. Stool sample for RNA extraction and genotyping was available in 86% (n = 280) of NoVGE cases (2015, n = 91; 2016, n = 189). Dominant capsid types detected in 75% (n = 210) samples were, GII.4 (63.8%, n = 134), GII.3 (15.2%, n = 32), GII.17 (6.7%, n = 14), and GII.6 (5.2%, n = 11). Prevailing RNA polymerase types found in 77% (n = 215) samples were GII.P31 (51.1%, n = 110), GII.P21 (17.7%, n = 38), GII.P4 (11.2%, n = 24), and GII.P7 (6.5%, n = 14). Both regions were typeable for 67% (n = 189) of samples. Most prevalent strains were GII.4Sydney_2012[P31] (48.7%, n = 92), GII.3[P21] (15.3%, n = 29), GII.4Sydney_2012[P4] (5.8%, n = 11) and GII.17[P17] (5.8%, n = 11). Simpson's diversity index showed a significant difference between the age groups 1-4 and 5-9 years: D 0.64 (95% confidence interval [CI]: 0.55-0.73) versus 0.83 (95% CI: 0.81-0.86), respectively (p = 0.03). An accurate understanding of NoV strain diversity is important for control and preventive measures, especially in the postrotavirus vaccine era.

Rotavirus Strain Surveillance in Estonia After Introduction of Rotavirus Universal Mass Vaccination.

BACKGROUND: Estonia implemented the rotavirus (RV) vaccine into its national immunization program in July 2014. We aimed to determine circulating RV genotypes and the clinical profile by genotypes from February 1, 2015, to August 30, 2016, among children 0-18 years hospitalized due to rotavirus gastroenteritis (RVGE). METHODS: During an observational study in 7 Estonian hospitals, we determined the RV genotypes in stool samples of RVGE patients who met predetermined criteria. Shannon's diversity index (H´) and Simpson's index (D) was used to evaluate genotype diversity by season and age and to compare prevaccine period data (2007-2008) for children 0-4 years of age (n = 77) to corresponding data from the postvaccine period (2015-2016, n = 346). The Vesikari Clinical Severity Scoring System was used for clinical profile evaluation. RESULTS: Stool samples of 479 RVGE patients were genotyped. Seventy-seven percent of RVGE infections were caused by G4P[8] (n = 150, 31%), G1P[8] (n = 100, 21%), G9P[8] (n = 79, 16%), G2P[4] (n = 23, 5%), G4P[4] (n = 17, 4%). The prevailing genotypes varied seasonally. Diversity increased during the postvaccine period among age groups 0-4: H´1.42 (95% CI: 1.2-1.7) in the prevaccine era versus 1.8 (95% CI: 1.7-2) in the postvaccine era (P = 0.008), and D 0.6 (95% CI: 0.5-0.7) versus 0.78 (0.75-0.80) (P = 0.01), respectively. The off-season period presented higher diversity compared with in-seasons. G2P[8], G1P[8], G4P[4], G9P[8], and G8P[8] presented with a different clinical profile compared with others. CONCLUSION: Since the introduction of universal mass vaccination in Estonia, the circulating RV genotypes have changed compared with those reported in the prevaccine era. Our study adds to knowledge about RV genotype distribution in Europe and expected dynamics after RV universal mass vaccination and provides insight on the clinical profile of prevailing genotypes.

Acute gastroenteritis hospitalizations after implementation of universal mass vaccination against rotavirus.

BACKGROUND: Estonia implemented rotavirus universal mass vaccination (RV UMV) in July 2014. We aimed to describe changes in acute gastroenteritis (AGE) hospitalization during RV seasons before (2007-2013) and after (2015-2018) RV UMV and compare patient profile of hospitalized AGE patients aged 0-18 years during first two consecutive RV seasons 2015 vs 2016. METHODS: We described AGE hospitalization patterns pre-and post-vaccine era using Estonian Health Insurance Fund (HIF) database. During a two-year observational multicenter study in seven Estonian hospitals from 01st of February 2015 to 30th August 2016 we assessed patient profile of all patients who met pre-determined AGE criteria. RESULTS: In post-vaccine era AGE hospitalization rate decreased from 10 to 8 per 1000 population (RR 0.81, 95% CI 0.79-0.83) compared to pre-vaccine era. Decreased RV seasonal activity, 81% (95% CI 77-84) and 55% (95% CI 52-58) reduction of rotavirus gastroenteritis (RVGE) hospitalization among age groups <1 and 1-4, respectively and upsurge of norovirus gastroenteritis (NoVGE) hospitalizations (RR = 1.8; 95% CI 1.6-1.9) was seen. In the multicenter observational study, among 2249 AGE patients hospitalized median age of RVGE patients increased from 2 to 3 years (p < 0.01) and duration of hospital stay decreased among RVGE, NoVGE and other GE patients during two consecutive RV seasons. According to Vesikari Clinical Severity Scoring System statistically significant change of severity score distribution in two RV seasons was seen (p < 0.001) with trend towards less severe AGE hospitalizations; 82.5% vs 70.5% severe cases in 2015 vs 2016, respectively. CONCLUSION: RV UMV lead to immediate and sustainable reduction of hospitalizations due to RVGE in children aged <4 years and reduction of overall AGE accompanied with the decrease in the severity of hospitalized children.

The concordance of the limiting antigen and the Bio-Rad avidity assays in persons from Estonia infected mainly with HIV-1 CRF06_cpx.

BACKGROUND: Serological assays to determine HIV incidence have contributed to estimates of HIV incidence, monitoring of HIV spread, and evaluation of prevention strategies. Two frequently used incidence assays are the Sedia HIV-1 LAg-Avidity EIA (LAg) and the Bio-Rad avidity incidence (BRAI) assays with a mean duration of recent infection (MDRI) of 130 and 240 days for subtype B infections, respectively. Little is known about how these assays perform with recombinant HIV-1 strains. We evaluated the concordance of these assays in a population infected mainly with HIV-1 CRF06_cpx. MATERIAL/METHODS: Remnant serum samples (n = 288) collected from confirmed, newly-diagnosed HIV-positive persons from Estonia in 2013 were tested. Demographic and clinical data were extracted from clinical databases. LAg was performed according to the manufacturer's protocol and BRAI testing was done using a validated protocol. Samples with LAg-pending or BRAI-invalid results were reclassified as recent if they were from persons with viral loads <1000 copies/mL or were reclassified as long-term if presenting with AIDS. RESULTS: In total 325 new HIV infections were diagnosed in 2013 in Estonia. Of those 276 persons were tested with both LAg and BRAI. Using assay results only, the recency rate was 44% and 70% by LAg and BRAI, respectively. The majority of samples (92%) recent by LAg were recent by BRAI. Similarly, 89% of samples long-term by BRAI were long-term by LAg. After clinical information was included in the analysis, the recency rate was 44% and 62% for LAg and BRAI, respectively. The majority of samples (86%) recent by LAg were recent by BRAI and 91% of long-term infections by BRAI were long-term by LAg. CONCLUSIONS: Comparison of LAg and BRAI results in this mostly CRF06_cpx-infected population showed good concordance for incidence classification. Our finding of a higher recency rate with BRAI in this population is likely related to the longer MDRI for this assay.

Stable level of HIV transmitted drug resistance in Estonia despite significant scale-up of antiretroviral therapy.

BACKGROUND: Due to the widespread use of non-nucleoside reverse transcriptase inhibitors (NNRTI) as part of first-line therapies to curb the human immunodeficiency virus (HIV) epidemic in Eastern-European countries, transmitted drug resistance (TDR) is of serious concern in this region. Therefore, TDR and its associated risk factors were investigated among newly diagnosed HIV-1 subjects in Estonia. METHODS: This nationwide observational study included all newly diagnosed HIV-1 subjects from January 1 until December 31, 2013. Demographic and clinical data were collected using the national surveillance system and the Estonian HIV-positive patient database (E-HIV). Starting from RNA, the HIV-1 protease (PR) and reverse transcriptase (RT) region was sequenced and surveillance drug resistance mutations (SDRM) were determined. Sequences from previous studies in Estonia and from public databases were included to study epidemic trends and to determine TDR clusters by phylogenetic analysis. RESULTS: Out of 325 newly diagnosed HIV-1 infections, 224 were successfully sequenced (68%). As in previous studies from Estonia, the circulating recombinant form CRF06_cpx was the most prevalent HIV subtype (164/224, 74%). Fifteen strains displayed SDRM, giving a TDR rate of 6.7% (95% CI 3.9; 11.0). The most common SDRMs were associated with NNRTI (10/15, 4.5%), followed by PI (3/15, 1.3%) and NRTI (2/15, 0.9%). K103 N (8/15, 53%) was the most common SDRM. The level of TDR and mutational patterns were comparable to previous years. Twenty-six transmission clusters containing Estonian sequences were observed, of which 23/26 belonged to CRF06_cpx and 2/26 displayed evidence of TDR. The only risk factor associated with the presence of TDR was imprisonment (OR 5.187, CI 1.139-25.565, p = 0.034). CONCLUSIONS: TDR remained stable at a moderate level in Estonia, K103N is the main SDRM with only one transmission-pair detected. We suggest screening for TDR at the time of diagnosis or prior to antiretroviral treatment initiation to tailor first-line regimens accordingly. SUMMARY: The third consecutive transmitted drug resistance (TDR) study demonstrated a stable TDR in Estonia. TDR reached 6.7% (moderate level) in 2013, with imprisonment being the only associated risk factor. Few drug resistance-associated transmission clusters were identified.

Association of IFNλ4 rs12979860 polymorphism with the acquisition of HCV and HIV infections among people who inject drugs.

We investigated the presence of a single-nucleotide polymorphism designated rs12979860 in the interferon λ4 (IFNλ4) gene among 345 people who inject drugs (PWID) and 495 blood donors to evaluate associations between the rs12979860 genotypes and human immunodeficiency virus/hepatitis C virus (HIV/HCV). The rs12979860 TT genotype was over-represented among HIV+ PWID than HIV- PWID and blood donors (16% vs 8% and 10%, P = 0.03, respectively). PWID with TT genotype had approximately twice the probability of being HIV+ (odds ratio [OR], 2.19; 95% confidence interval [CI], 1.11 to 4.33) than PWID without TT. Every additional year of intravenous drug use (IVDU) decreased the OR 1.16 times (OR, 0.86; 95% CI, 0.75 to 0.98). This suggests that rs12979860 TT increases susceptibility to HIV and this impact decreases with increasing duration of IVDU.

Prevalence and genotypes of GBV-C and its associations with HIV infection among persons who inject drugs in Eastern Europe.

We aimed to determine the rate of GBV-C viremia, seropositivity, and genotypes among people who inject drugs (PWID) and healthy volunteers in Estonia and to evaluate associations between GBV-C and sociodemographic factors, intravenous drug use, co-infections. The study included 345 Caucasian PWID and 118 healthy volunteers. The presence of GBV-C RNA (viremia) was determined by reverse transcriptase-nested PCR in 5' long terminal repeat. PCR products were sequenced and genotyped by phylogenetic analysis. GBV-C seropositivity was determined by ELISA. One third of PWID (114/345) and 6% (7/118) of healthy volunteers (OR = 7.8, 95% CI = 3.5-20.5, P < 0.001) were GBV-C viremic. In PWID group, 79% of sequences belonged to subtype 2a, 19% to subtype 2b, and two remained unclassified. In healthy volunteers, six out of seven sequences belonged to subtype 2a and one to subtype 2b. We found HIV+ PWID to have two times increased odds of being GBV-C viremic compared to HIV- PWID (62% vs. 38%; OR = 2.13, 95% CI = 1.34-3.36, P = 0.001). In addition, odds of being GBV-C viremic decreased with increasing age (OR = 0.94, 95% CI = 0.90-0.98, P = 0.001). HIV positivity remained associated with GBV-C viremia in multivariate analysis after adjustment for age (OR = 2.23, 95% CI = 1.39-3.58, P = 0.001). GBV-C seropositivity was similar among PWID and healthy volunteers (2.3% vs. 1.7%, respectively; OR = 1.4, 95% CI =0.3-13.5, P = 1). In an Eastern European country we demonstrated that GBV-C viremia is common among PWID, but uncommon among healthy volunteers, and GBV-C seropositivity is infrequent among both groups. Similarly to other European countries and USA, GBV-C 2a is the most common genotype in Estonia. J. Med. Virol. 89:632-638, 2017. © 2016 Wiley Periodicals, Inc.

T Cell Distribution in Relation to HIV/HBV/HCV Coinfections and Intravenous Drug Use.

Intravenous drug use (IDU) is one of the most important transmission routes for blood borne viruses, including human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). These infections alter the subset distributions of T cells; however, knowledge of such effects during HIV, HBV, and or HCV coinfection is limited. Therefore, we aimed to evaluate any associations between T cell distribution and the presence of HIV, HBV, and HCV coinfections among persons who inject drugs (PWID). Blood samples from 88 Caucasian PWID (mean age 30; 82% male) and 47 age-matched subjects negative for all three infections (mean age of 29; 83% male) were analyzed. The T cell markers CD3, CD4, CD8, CD45RA, CCR7, HLA-DR, and CCR5 were assessed using flow cytometry. Of the PWID, 40% were HIV+HBV+HCV+, 20% HBV+HCV+, 19% HCV+, and 13% negative for all three infections. The HIV+HBV+HCV+ PWID had lower percentages of CD4+ and higher percentages of CD8+ cells compared to triple negative PWID (p < 0.001 in all cases). The only difference between HBV+HCV+ with triple negative PWID was the lower CD4+ cell percentages among the former (52.1% and 58.6%, p = 0.021). Triple negative PWID had higher immune activation and number of CCR5+ cells compared to the controls. We suggest that the altered T cell subset distribution among PWID is mainly triggered by HIV infection and or IDU, while HBV and or HCV seropositivity has minimal additional effects on CD4+ cell distribution.

A CCL5 Haplotype Is Associated with Low Seropositivity Rate of HCV Infection in People Who Inject Drugs.

OBJECTIVE: The role of CC chemokine receptor 5 (CCR5) and its ligand CCL5 on the pathogenesis of HIV infection has been well studied but not for HCV infection. Here, we investigated whether CCL5 haplotypes influence HIV and HCV seropositivity among 373 Caucasian people who inject drugs (PWID) from Estonia. METHODS: Study included 373 PWID; 56% were HIV seropositive, 44% HCV seropositive and 47% co-infected. Four CCL5 haplotypes (A-D) were derived from three CCL5 polymorphisms (rs2107538/rs2280788/rs2280789) typed by Taqman allelic discrimination assays. The data of CCR5 haplotypes were used from our previous study. The association between CCL5 haplotypes with HIV and/or HCV seropositivity was determined using logistic regression analysis. RESULTS: Possessing CCL5 haplotype D (defined by rs2107538A/rs2280788G/rs2280789C) decreased the odds of HCV seropositivity compared to those not possessing it (OR = 0.19; 95% CI 0.09-0.40), which remained significant after adjustment to co-variates (OR = 0.08; 95% CI 0.02-0.29). An association of this haplotype with HIV seropositivity was not found. In step-wise logistic regression with backward elimination CCL5 haplotype D and CCR5 HHG*1 had reduced odds for HCV seropositivity (OR = 0.28 95% CI 0.09-0.92; OR = 0.23 95% CI 0.08-0.68, respectively) compared to those who did not possess these haplotypes, respectively. CONCLUSIONS: Our results suggest that among PWID CCL5 haplotype D and CCR5 HHG*1 independently protects against HCV. Our findings highlight the importance of CCL5 genetic variability and CCL5-CCR5 axis on the susceptibility to HCV.

Human T-lymphotropic virus types 1 and 2 are rare among intravenous drug users in Eastern Europe.

BACKGROUND: In Europe, human T-lymphotropic virus (HTLV) type 2 mainly occurs among intravenous drug users (IDUs) with prevalence up to 15% and HTLV-1 among general population with prevalence <1%. However, there is no data regarding the prevalence of HTLV-1 or HTLV-2 in Eastern European IDUs population where HIV prevalence is relatively high. We aimed to determine the prevalence and genotypes of HTLV-1/HTLV-2 among IDUs and healthy volunteers in Estonia. METHODS: The study included 345 IDUs and 138 healthy volunteers. The presence of HTLV-1/HTLV-2 was determined by nested PCR; positive and negative controls were used in every PCR run. RESULTS: The analysed IDUs resembled the IDUs of HIV epidemic in Estonia: mainly male (79%) with median age of 30years (interquartile range [IQR] 25-34), and prolonged duration of intravenous drug usage (11years; IQR 7-14). The prevalence exposure to blood-borne viral infections was high - 50% were HIV positive, 88% hepatitis C positive, 67% hepatitis B positive. Of IDUs, 64% reported receptive needle sharing in the past and 18% at least once a month during last six months. None of the IDUs carried HTLV-1 but there was a case of HTLV-2 (prevalence 0.3%; 95% CI 0.1-1.6). All healthy volunteers were HTLV-1 and HTLV-2 PCR negative. CONCLUSION: This is the first study investigating the prevalence of HTLV-1/HTLV-2 among high risk population and healthy volunteers in Eastern European region. Our results suggest that despite other widely spread blood-borne infections (e.g. HIV, HBV, HCV) HTLV-1 and HTLV-2 are rare among IDUs in Estonia.

Prevalence of drug resistance mutations in HAART patients infected with HIV-1 CRF06_cpx in Estonia.

HIV-1 drug resistance mutations (DRMs) and substitutions were assessed after the failure of the first line non-nucleoside reverse transcriptase inhibitors (NNRTIs) + 2 nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) treatment regimens (efavirenz [EFV] + lamivudine[3TC] + zidovudine [ZDV] vs. EFV + 3TC + ddI) among the HIV-1 CRF06_cpx infected subjects in Estonia. HIV-1 genomic RNA was sequenced; DRMs and amino acid substitutions were compared in 44 treatment naïve and 45 first-line NNRTI + 2 NRTI treatment failed patients consisting of EFV + 3TC + ZDV (n = 17) and EFV + 3TC + didanosine[ddI] (n = 21) therapy failed sub-populations. At least one DRM was found in 78% of treatment experienced patients. The most common NRTI mutations were M184V (80%), L74V (31%), L74I (17%), K219E (9%), and M184I (9%), NNRTI mutations were K103N (83%), P225H (14%), L100I (11%), and Y188L (11%), reflecting generally the similar pattern of DRMs to that seen in treatment failed subtype B viruses. Sub-population analysis revealed that EFV + 3TC + ddI failed patients had more DRMs compared to EFV + 3TC + ZDV failed patients, especially the ddI DRM L74IV and several additional NNRTI DRMs. Additionally, CRF06_cpx specific mutation E179V and substitutions R32K, K122E, and V200AE were also detected in treatment experienced population. After the failure of the first-line EFV + 3TC + ddI therapy HIV-1 CRF06_cpx viruses develop additional NRTI and NNRTI mutations compared to EFV + 3TC + ZDV regimen. Therefore the usage of EFV + 3TC + ddI in this subtype decreases the options for next regimens containing abacavir, and NNRTI class agents.

Differences in T cell distribution and CCR5 expression in HIV-positive and HIV-exposed seronegative persons who inject drugs.

Some individuals remain uninfected despite repeated exposure to HIV. This protection against HIV has been partly associated with altered T cell subset distributions and CCR5 expression levels. However, the majority of studies have been conducted in sexually exposed subjects. We aimed to assess whether HIV infection and intravenous drug use were associated with differences in CCR5 expression, immune activation on the CD4+ and CD8+ T cells and T cell distribution among Caucasian persons who inject drugs (PWIDs). Analyses of the data from 41 HIV-positive PWIDs, 47 HIV-exposed seronegative PWIDs (ESNs) and 47 age- and gender-matched HIV-negative non-drug users are presented. Of all of the study subjects, 111 (82 %) were male, and the median age was 29 years. T cell phenotyping was performed in peripheral blood mononuclear cells with multicolour flow cytometry using anti-CD3, CD4, CD8, CD45RA, CD45RO, HLA-DR and CCR5 antibodies. The ESNs exhibited greater levels of immune activation and higher percentages of CD4+ CD45RA+RO+ and CD8+ CD45RA+RO+ cells compared to the controls but not the HIV-positive people. The CCR5 expression on the CD4+ T cell subsets in the ESNs was lower than that in the controls but similar to that the HIV positives. The percentages of CCR5+ T cells were similar in all study groups and in most of the studied cell populations. Intravenous drug use was similarly associated with differences in T cell subset distributions and CCR5 expression among both the HIV-positive and HIV-negative PWIDs compared with the controls.

Influence of interleukin 10 polymorphisms -592 and -1082 to the HIV, HBV and HCV serostatus among intravenous drug users.

BACKGROUND: Interleukin 10 (IL-10) is a multifunctional cytokine produced by macrophages, monocytes, and T-helper cells. Two polymorphisms at positions -592 and -1082 have been associated with HIV susceptibility. However, their associations with susceptibility to HIV and its co-infections among intravenous drug users (IDUs) are largely unknown. METHODS: A total of 345 IDUs were recruited. Of the 173 HIV negative IDUs, 20 were classified as highly exposed HIV seronegative subjects (HESNs). A control group consisted of 496 blood donors; all HIV, HCV, and HBV negative. The IL-10-592C/A and -1082A/G were determined using TaqMan allelic discrimination assay. RESULTS: Of the IDUs, 50% were HIV positive, 89% HCV positive, 67% HBV positive and 41% had triple infection. IL-10-592C allele and -1082A allele were the most common and the -1082AG/-592CC was the most common genotype pair. All HESNs exhibited -1082A allele as compared to 81.4% of the HIV positive IDUs and 79% of donors (p=0.029 and p=0.019, respectively). None of HESNs had GG/CC genotype pair compared with 18.6% of HIV positive IDUs and 21.0% of donors (p=0.029 and p=0.019, respectively). The possession of -592AC and genotype pair AG/AC were associated with the decreased odds of HBV infection (OR=0.28; 95% CI 0.09-0.87; p=0.028 and OR=0.19; 95% CI 0.06-0.61; p=0.052, respectively). CONCLUSIONS: The presence of low producing IL-10-1082A and -592A alleles and their containing genetic variants protect highly exposed IDUs against acquisition of HIV and HBV infections.

Transmitted drug resistance is still low in newly diagnosed human immunodeficiency virus type 1 CRF06_cpx-infected patients in Estonia in 2010.

The presence of transmitted drug resistance (TDR) in treatment-naive HIV-1-positive subjects is of concern, especially in the countries of the former Soviet Union in which the number of subjects exposed to antiretrovirals (ARV) has exponentially increased during the past decade. We assessed the rate of TDR among newly diagnosed subjects in Estonia in 2010 and compared it to that in 2008. The study included 325 subjects (87% of all subjects tested HIV positive from January 1 to December 31, 2010). Of the 244 sequenced viral genomic RNA in the reverse transcriptase (RT) region 214 were CRF06_cpx, nine were subtype A1, three (one each) were subtype B and subtype C, CRF02_AG, and CRF03_AB; 15 viruses remained unclassified as putative recombinant forms between CRF06_cpx and subtype A1. HIV-1 TDR mutations in 2010 and 2008 (n=145) occurred at similar frequency in 4.5% (95% CI 2.45; 7.98) and 5.5% (95% CI 1.8; 9.24) of the patients, respectively. In 2010, 2.5% (6/244) of the sequences harbored nonnucleoside reverse transcriptase inhibitor (NNRTI) (K103N and K101E), 1.6% (4/244) nucleoside reverse transcriptase inhibitor (NRTI) (M41L, M184I, and K219E), and 0.4% (1/244) protease inhibitor (PI) (V82A) mutations. Our findings indicate that in spite of the increased consumption of ARVs the rate of TDR in Estonia has remained unchanged over the past 3 years. Similar stabilizing or even decreasing trends have been described in Western Europe and North America albeit at higher levels and in different socioeconomic backgrounds.

Association between TLR3 rs3775291 and resistance to HIV among highly exposed Caucasian intravenous drug users.

BACKGROUND: TLR3 recognizes dsRNA and triggers immune responses against RNA and DNA viruses. A polymorphism in TLR3, rs3775291 (Leu412Phe), has been associated with the increased susceptibility to enteroviral myocarditis, protection against tick-borne encephalitis virus and HIV-1 infection. We investigated Caucasian intravenous drug users (IDUs) and blood donors in order to evaluate the associations between TLR3 genotypes and susceptibility to HIV infection. MATERIALS AND METHODS: A total of 345 Caucasian IDUs were recruited, 50% of them were HIV positive, 89% HCV and 77% HBV positive. Based on their history of needle sharing, 20 of the HIV negative IDUs were classified as highly exposed HIV seronegatives (HESNs), 68 as non-HESNs and 85 as unexposed. The control group consisting of 497 blood donors tested negative for all three viruses. TLR3 rs3775291 were determined by using TaqMan Allelic Discrimination Assay. RESULTS: The TLR3 rs3775291 T allele frequency was similar among the HIV negative and HIV positive IDUs and blood donors - 36%, 31% and 34%, respectively. The frequency of persons possessing at least one TLR3 rs3775291 T allele was significantly higher in HESNs compared with blood donors and HIV positive IDUs (80% vs. 55%; p=0.037 and 80% vs. 53%; p=0.031, respectively). In the univariate analysis, persons who possessed at least one T allele had reduced odds of being HIV seropositive (OR=0.29, 95% CI=0.09-0.90). This association remained significant (OR=0.25, 95% CI=0.07-0.87) after the adjustment for other co-variates (HCV, HBV serostatus and duration of intravenous drug use). CONCLUSIONS: The TLR3 rs3775291 T allele has a protective effect against HIV infection among HESNs IDUs.