HCV reflex testing: A single-sample, low-contamination method that improves the diagnostic efficiency of HCV testing among patients in Alberta, Canada.

BACKGROUND: Hepatitis C virus (HCV) can be cured with antiviral treatments. Diagnosis normally requires two blood samples, one for serology screening and one for molecular confirmation. This multi-step process creates barriers in patient care and decreases testing for hard-to-reach populations. We used the cobas® 6800 to detect HCV RNA after antibody testing to investigate whether a single-sample reflex testing method is effective and efficient for diagnosing HCV-positive patients. METHODS: HCV RNA-positive clinical samples (n = 152) were interchangeably loaded on the ARCHITECT i2000SR with negative samples (n = 152) in a checkerboard fashion, tested for HCV antibodies using fixed probes, and directly transferred to the cobas 6800 for molecular testing. Contamination rates, sensitivity, and specificity were determined by comparing Abbott m2000 and cobas 6800 viral loads. After implementing reflex testing, clinical data over a 6-month period were analyzed for diagnostic efficiency. RESULTS: Contamination was present in 5 of 152 pairs (3.29%) after reflex testing. Sensitivity and specificity were 99.3% (95% CI 95.1% to 99.9%) and 100% (95% CI 97.5% to 100%), respectively, using the cobas 6800 assay after serotesting. Approximately 97% of clinical patients received a conclusive test result with the reflex-testing algorithm. For HCV-positive patients, mean diagnostic turnaround times were significantly lower using reflex testing versus the two-sample method (4 versus 39 days; p < 0.0001). CONCLUSIONS: HCV reflex testing demonstrated low levels of contamination without compromising the integrity of the molecular assay. Implementation in clinical laboratories would increase the efficiency of diagnosis and decrease steps in the continuum of care for patients.

HISTORIQUE: Il est possible de vaincre le virus de l'hépatite C (VHC) par des traitements antirétroviraux. Pour poser un diagnostic, il faut normalement deux prélèvements de sang : l'un pour le dépistage sérologique et l'autre pour la confirmation moléculaire. Ce processus en plusieurs étapes crée des obstacles dans les soins aux patients et limite le dépistage auprès des populations difficiles à atteindre. Les auteurs ont utilisé la plateforme cobasMD 6800 pour déceler l'ARN du VHC après des tests de détection des anticorps et pour explorer si une méthode de dépistage réflexe à échantillon unique est efficace et efficiente lors du diagnostic des patients positifs au VHC. MÉTHODOLOGIE : Les chercheurs ont placé les échantillons cliniques positifs à l'ARN du VHC (n = 152) en échiquier avec des échantillons négatifs (n = 152) dans l'analyseur ARCHITECT i2000SR, ont dépisté les anticorps du VHC à l'aide de sondes fixes, puis ont transféré les échantillons directement sur la plateforme cobas 6800 en vue du test moléculaire. Ils ont établi les taux de contamination, la sensibilité et la spécificité en comparant les charges virales des plateformes Abbott m2000 et cobas 6800. Après le dépistage réflexe, ils ont analysé les données cliniques sur une période de six mois pour en établir l'efficience diagnostique. RÉSULTATS : Les chercheurs ont constaté une contamination dans cinq des 152 paires (3,29 %) après le dépistage réflexe. Après l'examen sérologique, ils ont obtenu une sensibilité de 99,3 % (IC à 95 %, de 95,1 % à 99,9 %) et une spécificité de 100 % (IC à 95 %, de 97,5 % à 100 %) au moyen de la plateforme cobas 6800. Environ 97 % des patients cliniques ont reçu un test concluant selon l'algorithme du dépistage réflexe. Chez les patients positifs au VHC, le délai diagnostique moyen était considérablement plus court après le dépistage réflexe qu'après la méthode à deux échantillons (quatre jours plutôt que 39; p < 0,0001). CONCLUSIONS : Le dépistage réflexe du VHC a démontré de faibles taux de contamination sans compromettre l'intégrité du dosage moléculaire. Son adoption en laboratoire clinique accroîtrait l'efficience du diagnostic et réduirait le nombre d'étapes dans le continuum des soins aux patients.

Seropositivity to SARS-CoV-2 in Alberta, Canada in a post-vaccination period (March 2021-July 2021).

BACKGROUND: The COVID-19 pandemic has necessitated the need to rapidly make public health decisions. We systematically evaluated SARS-CoV-2 seropositivity to understand local COVID-19 epidemiology and support evidence-based public health decision making. METHODS: Residual blood samples were collected for SARS-CoV-2 receptor binding domain (RBD) IgG testing over a 1-5 day period monthly from 26 February 2021-9 July 2021 from six clinical laboratories across the province of Alberta, Canada. Monthly crude and adjusted (for age and gender) seropositivity were calculated. Results were linked to provincial administrative, laboratory, and vaccine databases. RESULTS: 60,632 individual blood samples were tested. Vaccination data were available for 98.8% of samples. Adjusted RBD IgG positivity rose from 11.9% (95% confidence interval [CI] 11.9-12.0%) in March 2021 to 70.2% (95% CI 70.2-70.3%) in July 2021 (p < .0001). Seropositivity rose from 9.4% (95% CI 9.3-9.4%) in March 2021 to 20.2% (95% CI 20.1-20.2%) in July 2021 in unvaccinated Albertans. Unvaccinated seropositive individuals were from geographic areas with significantly (p < .001) lower median household income, lower proportion of married/common-law relationships, larger average household size and higher proportions of visible minorities compared to seronegative unvaccinated individuals. In July 2021, the age groups with the lowest and highest seropositivity in unvaccinated Albertans were those ≥80 years (12.0%, 95% CI 5.3-18.6%) and 20-29 years (24.2%, 95% CI 19.6-28.8%), respectively. Of seropositive unvaccinated individuals, 50.2% (95% CI 45.9-54.5%) had no record of prior SARS-CoV-2 molecular testing. CONCLUSIONS: Longitudinal surveillance of SARS-CoV-2 seropositivity with data linkage is valuable for decision-making during the pandemic.

Evaluation of Diagnostic Accuracy of Eight Commercial Assays for the Detection of Rubella Virus-Specific IgM Antibodies.

Rubella and congenital rubella syndrome are caused by the rubella virus and are preventable through vaccination, making disease eradication possible. Monitoring of progress toward global eradication and local elimination requires high-quality, sensitive disease surveillance that includes laboratory confirmation of cases. Previous evaluations of anti-rubella IgM detection methods resulted in the broad adoption of the Enzygnost (most recently manufactured by Siemens) enzyme-linked immunosorbent assay (ELISA) kits within WHO's global measles and rubella laboratory network, but they have been discontinued. This study evaluated seven comparable ELISAs from six manufacturers (Trinity Biotech, Euroimmun, Clin-Tech, NovaTec and Virion\Serion) as well as one automated chemiluminescent assay (CLIA) from DiaSorin. These assays include three IgM capture assays and five indirect ELISAs. A panel of 238 sera was used for the evaluation that included 38 archival rubella IgM-positive sera and 200 sera collected from patients with symptomatically similar diseases, such as measles, dengue, parvovirus B19 infection, and roseola. With this panel of sera, the sensitivity of the methods ranged from 63.2% to 100% and the specificity from 80.0% to 99.5%. No single method had both sensitivity and specificity of >90%, unless sera with equivocal results were considered presumptively positive. Some assays, particularly the Serion ELISA, had a large number of false positives with parvovirus B19 IgM-positive sera as well as sera from confirmed measles cases. The performance characteristics identified in this evaluation serve as a reminder to not rely solely on rubella IgM results for case confirmation in elimination settings.

Stability of SARS-CoV-2 IgG in multiple laboratory conditions and blood sample types.

BACKGROUND: COVID-19 seroprevalence studies use serum/plasma samples to detect SARS-CoV-2 IgG. Data supporting alternate specimen types and freeze-thaw antibody stability is lacking. The stability of IgG and other immunoglobulins in multiple blood sample types stored in differing conditions and multiple freeze-thaw cycles (FTCs) was evaluated. MATERIALS AND METHODS: Serum, plasma, and heparinized-plasma samples were collected from COVID-19 recovered individuals. Samples underwent testing for SARS-CoV-2 antibodies upon collection, after each of 10-12 FTCs, and storage at -70°C, -20°C, 4°C, and room-temperature for 10-12 days using four high-throughput commercial assays, two rapid-test cassettes, a manual ELISA, and a surrogate neutralization assay. RESULTS: All three specimen types were collected from 34 COVID-19 recovered seropositive individuals (≥21 days post-symptoms). Using the Architect and Liaison assays, a positive qualitative SARS-CoV-2 IgG result was detected daily up to 12 FTCs and up to 10 days of storage at different temperatures. An additional 25 plasma samples consistently demonstrated detection of SARS-CoV-2 antibodies daily after 12 FTCs and storage at -20°C using two rapid test cassette assays (SD Biosensor and Hangzhou All Test), manual (Beijing Wantai) and surrogate neutralization (GenScript) ELISAs, and two high-throughput assays (Roche Elecsys nucleocapsid and spike). IgM antibodies were less frequently detected by one of the rapid test cassette assays. CONCLUSIONS: Serum, plasma, and heparinized-plasma constitute reliable samples for SARS-CoV-2 antibody detection. In particular, the IgG response was stable and reliably detected after multiple FTCs and storage at common laboratory conditions. IgM detection was variable due to the labile nature of this antibody class.

Detection of SARS-CoV-2 antibodies formed in response to the BNT162b2 and mRNA-1237 mRNA vaccine by commercial antibody tests.

BACKGROUND: With rapid approval of SARS-CoV-2 vaccines, the ability of clinical laboratories to detect vaccine-induced antibodies with available high-throughput commercial assays is unknown. We aimed to determine if commercial serology assays can detect vaccine-induced antibodies (VIAs) and understand the vaccination response. METHODS: This cohort study recruited healthcare workers and residents of long-term care facilities (receiving the BNT162b2 and mRNA-1273 products, respectively) who underwent serum collection pre-vaccination (BNT162b2 group), 2-weeks post vaccination (both groups), and pre-2nd dose (both groups). Sera were tested for the presence of SARS-CoV-2 IgG using four commercial assays (Abbott SARS-CoV-2 IgG, Abbott SARS-CoV-2 IgG II Quant, DiaSorin Trimeric S IgG, and GenScript cPASS) to detect VIAs. Secondary outcomes included description of post-vaccination antibody response and correlation with neutralizing titers. RESULTS: 225 participants (177 receiving BNT162b2 and 48 receiving mRNA-1273) were included (median age 41 years; 66-78% female). Nucleocapsid IgG was found in 4.1% and 21.9% of the BNT162b2 (baseline) and mRNA-1273 (2-weeks post first dose). All anti-spike assays detected antibodies post-vaccination, with an average increase of 87.2% (range 73.8-94.3%; BNT162b2), and 25.2% (range 23.8-26.7%; mRNA-1273) between the first and last sampling time points (all p < 0.05). Neutralizing antibodies were detected at all post-vaccine timepoints for both vaccine arms, with increasing titers over time (all p < 0.05). CONCLUSIONS: Anti-spike vaccine-induced SARS-CoV-2 IgG are detectable by commercially available high-throughput assays and increases over time. Prior to second dose of vaccination, neutralizing antibodies are detectable in 73-89% of individuals, suggesting most individuals would have some degree of protection from subsequent infection.

Pre-Vaccine Positivity of SARS-CoV-2 Antibodies in Alberta, Canada during the First Two Waves of the COVID-19 Pandemic.

We systematically evaluated SARS-CoV-2 IgG positivity in a provincial cohort to understand the local epidemiology of COVID-19 and support evidence-based public health decisions. Residual blood samples were collected for serology testing over 5-day periods monthly from June 2020 to January 2021 from six clinical laboratories across the province of Alberta, Canada. A total of 93,993 individual patient samples were tested with a SARS-CoV-2 nucleocapsid antibody assay with positives confirmed using a spike antibody assay. Population-adjusted SARS-CoV-2 IgG seropositivity was 0.92% (95% confidence interval [CI]: 0.91 to 0.93%) shortly after the first COVID-19 wave in June 2020, increasing to 4.63% (95% CI: 4.61 to 4.65%) amid the second wave in January 2021. There was no significant difference in seropositivity between males and females (1.39% versus 1.27%; P = 0.11). Ages with highest seropositivity were 0 to 9 years (2.71%, 95% CI: 1.64 to 3.78%) followed by 20 to 29 years (1.58%, 95% CI: 1.12 to 2.04%), with the lowest rates seen in those aged 70 to 79 (0.79%, 95% CI: 0.65 to 0.93%) and >80 (0.78%, 95% CI: 0.60 to 0.97%). Compared to the seronegative group, seropositive patients inhabited geographic areas with lower household income ($87,500 versus $97,500; P < 0.001), larger household sizes, and higher proportions of people with education levels of secondary school or lower, as well as immigrants and visible minority groups (all P < 0.05). A total of 53.7% of seropositive individuals were potentially undetected cases with no prior positive COVID-19 nucleic acid test (NAAT). Antibodies were detectable in some patients up to 9 months post positive NAAT result. This seroprevalence study will continue to inform public health decisions by identifying at-risk demographics and geographical areas. IMPORTANCE Using SARS-CoV-2 serology testing, we assessed the proportion of people in Alberta, Canada (population 4.4 million) positive for COVID-19 antibodies, indicating previous infection, during the first two waves of the COVID-19 pandemic (prior to vaccination programs). Linking these results with sociodemographic population data provides valuable information as to which groups of the population are more likely to have been infected with the SARS-CoV-2 virus to help facilitate public health decision-making and interventions. We also compared seropositivity data with previous COVID-19 molecular testing results. Absence of antibody and molecular testing were highly correlated (95% negative concordance). Positive antibody correlation with a previous positive molecular test was low, suggesting the possibility of mild/asymptomatic infection or other reasons leading individuals from seeking medical attention. Our data highlight that the true estimate of population prevalence of COVID-19 is likely best informed by combining data from both serology and molecular testing.

Evaluation of Diagnostic Accuracy of Eight Commercial Assays for the Detection of Measles Virus-Specific IgM Antibodies.

The World Health Organization (WHO) has targeted measles for global eradication through mass immunization. For effective monitoring of eradication targets, high-quality surveillance is needed. The detection of IgM antibodies, specific to the measles virus, with the use of commercial enzyme-linked immunosorbent assays (ELISA or EIA) is broadly used within the WHO global measles and rubella laboratory network for laboratory confirmation, and in particular, ELISA kits manufactured by Siemens (Enzygnost kits) have been primarily used. Spurred by the discontinuation of these kits, this study aims to report on the clinical sensitivity and specificity of comparable commercial ELISA kits and one automated chemiluminescent immunoassay (CLIA) method. A panel of 239 serum samples was assembled that included sera from confirmed measles cases (n = 50) and probable post-MMR vaccine response (n = 2). Measles-negative sera (n = 187) were collected from individuals presenting with other fever and rash illnesses. A total of 7 ELISA kits (Euroimmun native antigens and recombinant nucleoprotein, IBL, Clin-Tech Microimmune, NovaTec NovaLisa, Serion, and Siemens Enzygnost) and one CLIA method (DiaSorin LIAISON XL) were evaluated. The ELISA kits included two IgM capture methods and five indirect methods. Calculated sensitivities and specificities ranged from 75.0% to 98.1% and 86.6% to 99.5%, respectively. The parvovirus B19 IgM positive sera were noted to cause false-positive results, particularly for the ELISA kits from Serion and NovaLisa; specificities for this subset of samples ranged from 51.4% to 100.0%. The capture IgM ELISA methods provided the best combination of sensitivity and specificity.

The INSTI HIV-1/HIV-2 antibody test: a review.

INTRODUCTION: Rapid HIV tests have been widely adopted globally as an important component of HIV prevention and control programs. The INSTI™ HIV-1/HIV-2 antibody test is a second-generation HIV antibody test, available in most countries for use from whole blood, serum, and plasma. AREAS COVERED: Available data on kit characteristics and current performance data on the INSTI™ HIV-1/HIV-2 antibody test are presented together with six other rapid point-of-care tests (RPOCTs) for HIV antibody. Few published data are available providing direct comparisons of INSTI™ with other RPOCTs for HIV antibody and standard laboratory-based HIV-1/HIV-2 antibody assays. Existing data showed that INSTI™ has comparable performance to other RPOCTs but detected seroconversion later than standard laboratory-based assays. EXPERT OPINION: The good performance of INSTI HIV-1/HIV-2 antibody test, its ease of use, the rapid availability of results (< 5 min), and the lack of specialized equipment required to use the kit make this kit a useful addition to the global market. The unique antigen and flow through technology contained in the kit make it a strong addition to HIV RPOCTs and to rapid/rapid algorithms used in many resource-limited settings.

Feasibility and Field Performance of a Simultaneous Syphilis and HIV Point-of-Care Test Based Screening Strategy in at Risk Populations in Edmonton, Canada.

Few studies have evaluated the feasibility of delivering syphilis point-of-care (POC) testing in outreach (nonclinical) settings in resource rich countries. The objectives of the study were to evaluate the feasibility and diagnostic performance of performing both HIV and syphilis POC testing in outreach settings and to document new cases identified in the study population. 1,265 outreach testing visits were offered syphilis and HIV POC testing and 81.5% (n = 1,031) consented to testing. In our population, the SD Bioline 3.0 Syphilis Test had a sensitivity of 85.3% [CI (68.9-95.0)], specificity of 100.0% [CI (99.6-100.0)], positive predictive value (PPV) of 100.0% [CI (88.1-100.0)], and negative predictive value (NPV) of 99.5% [CI (98.9-99.8)]. Test characteristics for the INSTI HIV-1/HIV-2 Antibody Test had a 100.0% sensitivity [CI (39.8-100.00], 99.8 specificity [CI (99.3-100)], 66.7% PPV [CI (22.3-95.7)], and 100.0% NPV [CI (99.6-100.0)]. Four new cases of syphilis and four new HIV cases were diagnosed. In summary, at risk population seeking STI testing found POC tests to be acceptable, the POC tests performed well in outreach settings, and new cases of syphilis and HIV were identified and linked to treatment and care.

Rapid HIV tests in acute care settings in an area of low HIV prevalence in Canada.

Rapid HIV testing has the potential to improve medical care and reduce the transmission of infection. In this study, rapid HIV testing was performed on serum samples in acute care settings in five hospitals from urban and rural regions using the INSTI™ HIV-1/HIV-2 Rapid Antibody Test (bioLytical Laboratories, Richmond, British Columbia). Parallel standard HIV antibody tests were performed at the provincial reference laboratory. Patient demographics, indication for testing and risk behaviours were collected. From April 30, 2007 and November 23, 2009, 1708 individuals were tested: 875 (50.3%) tests in pregnant women, 730 (42%) in source individuals in blood and body fluid exposures and 119 (5.8%) in acutely ill persons. Twenty-five (1.4%) samples were reactive by rapid HIV testing, of which 13 were reactive previously and 1 was a false reactive. Sensitivity of the rapid HIV test compared to standard HIV testing was 100%, specificity was 99.9%, the positive predictive value was 96% and the negative predictive value was 100%. The median time from specimen collection to availability of the rapid HIV result varied by site and ranged from 54 min to 1h 42 min. In this study, the INSTI™ HIV-1 Rapid Antibody test identified reactive and non-reactive samples with similar accuracy to the conventional testing algorithm and provided a reliable way to perform rapid HIV testing in acute care settings.

The use of donor and recipient screening for toxoplasma in the era of universal trimethoprim sulfamethoxazole prophylaxis.

BACKGROUND: Toxoplasmosis is a serious complication of solid organ transplantation. The highest risk of infection and disease occurs in heart recipients with primary infection transmitted by a seropositive donor to a seronegative recipient (donor-recipient mismatch). Toxoplasmosis has been reported to occur in noncardiac transplant recipients; however, no large studies examining the frequency of such events or the need for serologic screening exist. METHODS: A retrospective cohort study of 1,006 solid organ transplant recipients transplanted in our center between 1984 and 1997 was performed to examine the incidence of Toxoplasma seroconversion, reactivation, and clinical toxoplasmosis and to evaluate the impact of trimethoprim sulfamethoxazole (TMP/SMX) prophylaxis on these outcomes. RESULTS: Pretransplant Toxoplasma seroprevalence was 13.4% in donors and 17.8% in recipients. The incidence of Toxoplasma donor-recipient mismatch was 9.5% during the 14-year study period, and only 39.1% of mismatched recipients received TMP/SMX prophylaxis. Only four patients seroconverted, of whom two had received prophylaxis. There were no cases of clinical disease; either primary or reactivation. CONCLUSIONS: We therefore conclude that in transplant centers with low Toxoplasma seroprevalence, routine screening for Toxoplasma in solid organ donors and recipients is not necessary, particularly in the era of routine TMP/SMX prophylaxis.

A trial of valganciclovir prophylaxis for cytomegalovirus prevention in lung transplant recipients.

Cytomegalovirus (CMV) infection is common after lung transplantation. We performed a prospective trial of valganciclovir prophylaxis in lung recipients with outcomes compared to matched historical controls. The valganciclovir group (n = 40) (including D+/R- and R+ patients) was prospectively enrolled, and received oral valganciclovir 900 mg once daily for 12 weeks. Historical controls (n = 40) received 12 weeks of daily intravenous ganciclovir if D+/R- or 12 weeks of oral ganciclovir if R+. CMV viral load testing was done at two-week intervals until 6 months posttransplant. Baseline demographics and immunosuppression were comparable in the two groups. The incidence of CMV viremia was 16/40 (40.0%) in the valganciclovir arm versus 18/40 (45%) in the ganciclovir arm (p = NS). The incidence of symptomatic CMV disease was 8/40 (20%) versus 7/40 (17.5%), respectively (p = NS). In both groups viremia, while on prophylaxis, was uncommon (valganciclovir: 0/40 and ganciclovir: 2/40). Peak viral load and time to viremia were similar in the two arms. High rates of viremia and symptomatic disease occurred in the D+/R- patients after discontinuation of prophylaxis. Genotypic CMV sequence analysis demonstrated low rates of ganciclovir resistance in both groups. Valganciclovir prophylaxis had similar efficacy to either intravenous ganciclovir (D+/R- patients), or oral ganciclovir (R+ patients) in lung recipients.

Herpes simplex virus seroprevalence and risk factors in 2 Canadian sexually transmitted disease clinics.

OBJECTIVES: The objectives of this study were to determine the seroprevalence and risk factors for herpes simplex virus (HSV) types 1 and 2 in patients attending 2 Canadian sexually transmitted disease (STD) clinics. STUDY: Stored sera were tested for the presence of IgG class antibodies to HSV-1 and HSV-2 and results linked to that obtained from a risk behavior questionnaire. RESULTS: Overall prevalences for HSV-1 and -2 were 56% and 19%, respectively. HSV-1 and -2 seropositivity was associated with increasing age, female gender, nonwhite ethnicity, and a history of STD. HSV-2 seropositivity was also associated with a history of genital herpes, presence of genital sores, and coinfection with either human immunodeficiency virus (HIV) or hepatitis C (HCV). CONCLUSIONS: Herpes simplex infection is common in this high-risk Canadian population. Our finding that HCV seropositivity was a significant predictor for HSV-2 seropositivity emphasizes the overlap between pathogens that are primarily thought to be bloodborne pathogens and sexually transmitted infections and the need to target prevention in these areas concurrently.

Comparison of LightCycler-based PCR, COBAS amplicor CMV monitor, and pp65 antigenemia assays for quantitative measurement of cytomegalovirus viral load in peripheral blood specimens from patients after solid organ transplantation.

In order to evaluate the LightCycler-based PCR (LC-PCR) as a diagnostic assay technique, a classical pp65 antigenemia assay and the commercially available COBAS Amplicor CMV Monitor (CACM) assay were compared to the LC-PCR assay for the detection and quantitation of cytomegalovirus (CMV) load in 404 parallel specimens of peripheral blood from 66 patients after solid organ transplantation. A good correlation existed among these three assays (r congruent with 0.6, P < 0.0001). The LC-PCR assay was the most sensitive (54% of specimens positive) compared to the CACM (48.6%) and the pp65 antigenemia (26%) assays. The LC-PCR assay detected all samples found positive by using both the CMV pp65 antigenemia assay and the CACM assay. The LC-PCR also had the widest dynamic range (from 250 to 10(7) DNA copies/ml of plasma). No cross-reactions were found among CMV and Epstein-Barr virus, varicella-zoster virus, or herpes simplex virus in the LC-PCR by using amplification with specifically designed primer pairs. Precision, expressed as the coefficient of variation, was <3% with standard DNA from cell cultures and between 6.55 and 14.1% with clinical specimens in repeat LC-PCR runs. One run of the LC-PCR took half of the time required for the semiautomated CACM procedure. Because of its sensitivity, specificity, cost-effectiveness, and simplicity, the LC-PCR assay could replace the pp65 antigenemia and the CACM assays as the preferred technique for the surveillance, diagnosis, and monitoring of response of CMV diseases in high-risk populations.

Hepatitis C seroprevalence and risk behaviors in patients attending sexually transmitted disease clinics.

BACKGROUND: Hepatitis C virus (HCV) is a major global problem, transmitted primarily by percutaneous exposure to contaminated blood. GOAL: The goal of the study was to determine the seroprevalence of and risk factors for HCV among patients attending two urban STD clinics in Alberta. STUDY DESIGN: Anonymous unlinked serosurveys were performed with use of leftover sera. Self-administered questionnaires collected information on demographics, sexual behaviors, and drug use. RESULTS: The seroprevalence of HCV was 3.4% (209 of 6,668 patients). Univariate analysis revealed that infection was higher among nontherapeutic needle users (RR = 80.9), those coinfected with HIV (RR = 8.09), individuals over the age of 20 years (RR = 6.68), those of aboriginal ethnicity (RR = 5.54), those with a history of STD (RR = 3.43), men (RR = 2.2), and bisexuals (RR = 2.23). Not utilizing condoms and engaging in prostitution or exchanging money or drugs for sex were also risk factors. In multivariate analysis, nontherapeutic needle use remained highly significant (RR = 60.54-65.51). Other significant factors included sex, age, ethnicity, a history of STD, and HIV infection (RR = 1.72, 4.62, 3.18, 1.69, and 2.56, respectively). Sexual orientation and sexual practices were not significant without a history of drug use. CONCLUSION: Nontherapeutic needle use is the strongest predictor of HCV infection.