Gardnerella Revisited: Species Heterogeneity, Virulence Factors, Mucosal Immune Responses, and Contributions to Bacterial Vaginosis.

Gardnerella species are associated with bacterial vaginosis (BV) and have been investigated as etiological agents of the condition. Nonetheless, the isolation of this taxon from healthy individuals has raised important questions regarding its etiological role. Recently, using advanced molecular approaches, the Gardnerella genus was expanded to include several different species that exhibit differences in virulence potential. Understanding the significance of these different species with respect to mucosal immunity and the pathogenesis and complications of BV could be crucial to solving the BV enigma. Here, we review key findings regarding the unique genetic and phenotypic diversity within this genus, virulence factors, and effects on mucosal immunity as they stand. We also comment on the relevance of these findings to the proposed role of Gardnerella in BV pathogenesis and in reproductive health and identify key gaps in knowledge that should be explored in the future.

Clinical evaluation of the GeneXpert® Xpert® Xpress SARS-CoV-2/Flu/RSV PLUS combination test.

The GeneXpert® Xpert® Xpress SARS-CoV-2/Flu/RSV PLUS combination test (PLUS assay) received Health Canada approval in January 2022. The PLUS assay is similar to the SARS-CoV-2/Flu/RSV combination test, with modifications to improve assay robustness against circulating and emerging variants. The performance characteristics of the PLUS assay were assessed at the Lakeridge Health Oshawa Hospital Centre and the National Microbiology Laboratory of Canada. The PLUS assay was directly compared to the SARS-CoV-2/Flu/RSV combination test using SARS-CoV-2 culture from five variants and remnant clinical specimens collected across the coronavirus disease 2019 pandemic. This included 50 clinical specimens negative for all pathogens, 110 clinical specimens positive for SARS-CoV-2, influenza A, influenza B, RSVA, and(or) RSVB and an additional 11 mixed samples to screen for target interactions. The PLUS assay showed a high % agreement with the widely used SARS-CoV-2/Flu/RSV combination test. Based on these findings, the PLUS assay and the Xpert SARS-CoV-2/Flu/RSV combination test results are largely consistent with no observed difference in sensitivity, specificity, or time to result when challenged with various SARS-CoV-2 variants. The reported cycle threshold (Ct) values provided by the new PLUS assay were also unchanged, with the exception of a possible 1-2 decrease reported in Ct for RSVA across a limited sample size.

A cross-sectional survey exploring HIV and HCV prevalence among men who purchase sex in Dnipro, Ukraine.

BACKGROUND: HIV programming in Ukraine largely targets "key population" groups. Men who purchase sex are not directly reached. The aim of our study was to explore the prevalence of sexually transmitted and blood-borne infections (STBBIs) among men who purchase sex from female sex workers. METHODS: Following geographic mapping and population size estimation at each "hotspot", we conducted a cross-sectional bio-behavioural survey with men who purchase sex between September 2017 and March 2018 in Dnipro, Ukraine. Eligibility criteria included purchasing sex services at a "hotspot" and being ≥ 18 years. Participants completed a structured questionnaire, followed by HIV/HCV rapid testing and a dried blood spot (DBS) sample collection for confirmatory serology. RESULTS: The study enrolled 370 participants. The median age was 32 (interquartile range [IQR] = 27-38) and the median age of first purchase of sexual services was 22 (IQR = 19-27). Over half (56%) of participants reported ever testing for HIV; four participants (2%, N = 206) reported having tested positive for HIV, with three out of the four reporting being on ART. Forty percent of participants had ever tested for HCV, with three (2%, N = 142) having ever tested positive for HCV. In DBS testing, nine participants (2.4%) tested positive for HIV and 24 (6.5%) tested positive for ever having an HCV infection. CONCLUSION: Prevalence of HIV and HCV in this population was high. Given high rates of study enrolment and testing, efforts should be made to reach men who purchase sex with expanded STBBI programming.

A Sensitive and Rapid Wastewater Test for SARS-COV-2 and Its Use for the Early Detection of a Cluster of Cases in a Remote Community.

Throughout the coronavirus disease 2019 (COVID-19) pandemic, wastewater surveillance has been used to monitor trends in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) prevalence in the community. A major challenge in establishing wastewater surveillance programs, especially in remote areas, is the need for a well-equipped laboratory for sample analysis. Currently, no options exist for rapid, sensitive, mobile, and easy-to-use wastewater tests for SARS-CoV-2. The performance of the GeneXpert system, which offers cartridge-based, rapid molecular clinical testing for SARS-CoV-2 in a portable platform, was evaluated using wastewater as the input. The GeneXpert demonstrated a SARS-CoV-2 limit of detection in wastewater below 32 copies/mL with a sample processing time of less than an hour. Using wastewater samples collected from multiple sites across Canada during February and March 2021, a high overall agreement (97.8%) was observed between the GeneXpert assay and laboratory-developed tests regarding the presence or absence of SARS-CoV-2. Additionally, with the use of centrifugal filters, the detection threshold of the GeneXpert system was improved to <10 copies/mL in wastewater. Finally, to support on-site wastewater surveillance, GeneXpert testing was implemented in Yellowknife, a remote community in Northern Canada, where its use successfully alerted public health authorities to undetected transmission of COVID-19. The identification of SARS-CoV-2 in wastewater triggered clinical testing of recent travelers and identification of new COVID-19 cases/clusters. Taken together, these results suggest that GeneXpert is a viable option for surveillance of SARS-CoV-2 in wastewater in locations that do not have access to established testing laboratories. IMPORTANCE Wastewater-based surveillance is a powerful tool that provides an unbiased measure of COVID-19 prevalence in a community. This work describes a sensitive wastewater rapid test for SARS-CoV-2 based on a widely distributed technology, the GeneXpert. The advantages of an easy-to-use wastewater test for SARS-CoV-2 are clear: it supports surveillance in remote communities, improves access to testing, and provides faster results allowing for an immediate public health response. The application of wastewater rapid testing in a remote community facilitated the detection of a COVID-19 cluster and triggered public health action, clearly demonstrating the utility of this technology. Wastewater surveillance will become increasingly important in the postvaccination pandemic landscape as individuals with asymptomatic/mild infections continue transmitting SARS-CoV-2 but are unlikely to be tested.

Clinical Correlates of Human Immunodeficiency Virus-1 (HIV-1) DNA and Inducible HIV-1 RNA Reservoirs in Peripheral Blood in Children With Perinatally Acquired HIV-1 Infection With Sustained Virologic Suppression for at Least 5 Years.

BACKGROUND: The Early Pediatric Initiation Canada Child Cure Cohort (EPIC4) study is a prospective, multicenter, Canadian cohort study investigating human immunodeficiency virus-1 (HIV-1) reservoirs, chronic inflammation, and immune responses in children with perinatally acquired HIV-1 infection. The focus of this report is HIV-1 reservoirs and correlates in the peripheral blood of children who achieved sustained virologic suppression (SVS) for ≥5 years. METHODS: HIV-1 reservoirs were determined by measuring HIV-1 DNA in peripheral blood mononuclear cells and inducible cell-free HIV-1 RNA in CD4+ T-cells by a prostratin analogue stimulation assay. HIV serology was quantified by signal-to-cutoff ratio (S/CO). RESULTS: Of 228 enrolled participants, 69 achieved SVS for ≥5 years. HIV-1 DNA, inducible cell-free HIV-1 RNA, and S/COs correlated directly with the age of effective combination antiretroviral therapy (cART) initiation (P < .001, P = .036, and P < .001, respectively) and age when SVS was achieved (P = .002, P = .038, and P < .001, respectively) and inversely with the proportion of life spent on effective cART (P < .001, P = .01, and P < .001, respectively) and proportion of life spent with SVS (P < .001, P = .079, and P < .001, respectively). Inducible cell-free HIV-1 RNA correlated with HIV-1 DNA, most particularly in children with SVS, without virologic blips, that was achieved with the first cART regimen initiated prior to 6 months of age (rho = 0.74; P = .037) or later (rho = 0.87; P < .001). S/COs correlated with HIV-1 DNA (P = .003), but less so with inducible cell-free HIV-1 RNA (P = .09). CONCLUSIONS: The prostratin analogue stimulation assay, with its lower blood volume requirement, could be a valuable method for evaluating inducible HIV-1 reservoirs in children. Standard commercial HIV serology may be a practical initial indirect measure of reservoir size in the peripheral blood of children with perinatally acquired HIV-1 infection.

Assessing the influence of conflict on the dynamics of sex work and the HIV and HCV epidemics in Ukraine: protocol for an observational, ethnographic, and mathematical modeling study.

BACKGROUND: Armed conflict erupted in eastern Ukraine in 2014 and still continues. This conflict has resulted in an intensification of poverty, displacement and migration, and has weakened the local health system. Ukraine has some of the highest rates of HIV and Hepatitis C (HCV) in Europe. Whether and how the current conflict, and its consequences, will lead to changes in the HIV and HCV epidemic in Ukraine is unclear. Our study aims to characterize how the armed conflict in eastern Ukraine and its consequences influence the pattern, practice, and experience of sex work and how this affects HIV and HCV rates among female sex workers (FSWs) and their clients. METHODS: We are implementing a 5-year mixed methods study in Dnipro, eastern Ukraine. Serial mapping and size estimation of FSWs and clients will be conducted followed by bio-behavioral cross-sectional surveys among FSWs and their clients. The qualitative component of the study will include in-depth interviews with FSWs and other key stakeholders and participant diaries will be implemented with FSWs. We will also conduct an archival review over the course of the project. Finally, we will use these data to develop and structure a mathematical model with which to estimate the potential influence of changes due to conflict on the trajectory of HIV and HCV epidemics among FSW and clients. DISCUSSION: The limited data that exists on the effect of conflict on disease transmission provides mixed results. Our study will provide rigorous, timely and context-specific data on HIV and HCV transmission in the setting of conflict. This information can be used to inform the design and delivery of HIV and HCV prevention and care services.

Impact of pre-amplification conditions on sensitivity of the tat/rev induced limiting dilution assay.

Antiretroviral therapy (ART) can lower a patient's HIV plasma viral load to an undetectable level, but following cessation of ART viremia rapidly rebounds. It has been shown that ART does not eliminate latent viruses sequestered into anatomical and cellular reservoirs. Therefore, in patients that have ceased ART, the following rebound in HIV viremia is caused by the activation of latent HIV reservoirs. A major issue in HIV cure research is the quantification of these latent HIV reservoirs. Various reservoir measurement methods exist, but the gold standard technique remains the culture-based quantitative viral outgrowth assay (QVOA). Recently, a new PCR-based assay, named the tat/rev induced limiting dilution assay (TILDA) was described which measures the frequency of inducible latently infected CD4+ T cells that actively produce multiply-spliced RNA coding for the Tat/Rev proteins. The objective of this study was to further optimize the assay by examining the influence of varied factors, such as the amount of products transferred from the pre-amplification step to the PCR reaction, storage of pre-amplification products prior to PCR runs, and the number of cells used, on the assay's sensitivity and reproducibility. We also investigated whether the assay could be used to quantify HIV reservoirs in monocytes/macrophages.

Next-Generation Human Immunodeficiency Virus Sequencing for Patient Management and Drug Resistance Surveillance.

High-quality, simplified, and low-cost human immunodeficiency virus (HIV) drug resistance tests that are able to provide timely actionable HIV resistance data at individual, population, and programmatic levels are needed to confront the emerging drug-resistant HIV epidemic. Next-generation sequencing technologies embedded in automated cloud-computing analysis environments are ideally suited for such endeavor. Whereas NGS can reduce costs over Sanger sequencing, automated analysis pipelines make NGS accessible to molecular laboratories regardless of the available bioinformatic skills. They can also produce highly structured, high-quality data that could be examined by healthcare officials and program managers on a real-time basis to allow timely public health action. Here we discuss the opportunities and challenges of such an approach.

A novel strain of cynomolgus macaque cytomegalovirus: implications for host-virus co-evolution.

BACKGROUND: Cytomegaloviruses belong to a large, ancient, genus of DNA viruses comprised of a wide array of species-specific strains that occur in diverse array of hosts. METHODS: In this study we sequenced the ~217 Kb genome of a cytomegalovirus isolated from a Mauritius cynomolgus macaque, CyCMV Mauritius, and compared it to previously sequenced cytomegaloviruses from a cynomolgus macaque of Filipino origin (CyCMV Ottawa) and two from Indian rhesus macaques (RhCMV 180.92 and RhCMV 68-1). RESULTS: Though more closely related to CyCMV Ottawa, CyCMV Mauritius is less genetically distant from both RhCMV strains than is CyCMV Ottawa. Several individual genes, including homologues of CMV genes RL11B, UL123, UL83b, UL84 and a homologue of mammalian COX-2, show a closer relationship between homologues of CyCMV Mauritius and the RhCMVs than between homologues of CyCMV Mauritius and CyCMV Ottawa. A broader phylogenetic analysis of 12 CMV strains from eight species recovers evolutionary relationships among viral strains that mirror those amongst the host species, further demonstrating co-evolution of host and virus. CONCLUSIONS: Phylogenetic analyses of rhesus and cynomolgus macaque CMV genome sequences demonstrate co-speciation of the virus and host.

Characterization of the Drug Resistance Profiles of Integrase Strand Transfer Inhibitors in Simian Immunodeficiency Virus SIVmac239.

UNLABELLED: We previously showed that the simian immunodeficiency virus SIVmac239 is susceptible to human immunodeficiency virus (HIV) integrase (IN) strand transfer inhibitors (INSTIs) and that the same IN drug resistance mutations result in similar phenotypes in both viruses. Now we wished to determine whether tissue culture drug selection studies with SIV would yield the same resistance mutations as in HIV. Tissue culture selection experiments were performed using rhesus macaque peripheral blood mononuclear cells (PBMCs) infected with SIVmac239 viruses in the presence of increasing concentrations of dolutegravir (DTG), elvitegravir (EVG), and raltegravir (RAL). We now show that 22 weeks of selection pressure with DTG yielded a mutation at position R263K in SIV, similar to what has been observed in HIV, and that selections with EVG led to emergence of the E92Q substitution, which is a primary INSTI resistance mutation in HIV associated with EVG treatment failure. To study this at a biochemical level, purified recombinant SIVmac239 wild-type (WT) and E92Q, T97A, G118R, Y143R, Q148R, N155H, R263K, E92Q T97A, E92Q Y143R, R263K H51Y, and G140S Q148R recombinant substitution-containing IN enzymes were produced, and each of the characteristics strand transfer, 3'-processing activity, and INSTI inhibitory constants was assessed in cell-free assays. The results show that the G118R and G140S Q148R substitutions decreased Km' and Vmax'/Km' for strand transfer compared to those of the WT. RAL and EVG showed reduced activity against both viruses and against enzymes containing Q148R, E92Q Y143R, and G140S Q148R. Both viruses and enzymes containing Q148R and G140S Q148R showed moderate levels of resistance against DTG. This study further confirms that the same mutations associated with drug resistance in HIV display similar profiles in SIV. IMPORTANCE: Our goal was to definitively establish whether HIV and simian immunodeficiency virus (SIV) share similar resistance pathways under tissue culture drug selection pressure with integrase strand transfer inhibitors and to test the effect of HIV-1 integrase resistance-associated mutations on SIV integrase catalytic activity and resistance to integrase strand transfer inhibitors. Clinically relevant HIV integrase resistance-associated mutations were selected in SIV in our tissue culture experiments. Not only do we report on the characterization of SIV recombinant integrase enzyme catalytic activities, we also provide the first research anywhere on the effect of mutations within recombinant integrase SIV enzymes on drug resistance.

Simian-tropic HIV as a model to study drug resistance against integrase inhibitors.

Drug resistance represents a key aspect of human immunodeficiency virus (HIV) treatment failure. It is important to develop nonhuman primate models for studying issues of drug resistance and the persistence and transmission of drug-resistant viruses. However, relatively little work has been conducted using either simian immunodeficiency virus (SIV) or SIV/HIV recombinant viruses for studying resistance against integrase strand transfer inhibitors (INSTIs). Here, we used a T-cell-tropic SIV/HIV recombinant virus in which the capsid and vif regions of HIV-1 were replaced with their SIV counterparts (simian-tropic HIV-1 [stHIV-1](SCA,SVIF)) to study the impact of a number of drug resistance substitutions in the integrase coding region at positions E92Q, G118R, E138K, Y143R, S153Y, N155H, and R263K on drug resistance, viral infectivity, and viral replication capacity. Our results show that each of these substitutions exerted effects that were similar to their effects in HIV-1. Substitutions associated with primary resistance against dolutegravir were more detrimental to stHIV-1(SCA,SVIF) infectiousness than were resistance substitutions associated with raltegravir and elvitegravir, consistent with data that have been reported for HIV-1. These findings support the role of stHIV-1(SCA,SVIF) as a useful model with which to evaluate the role of INSTI resistance substitutions on viral persistence, transmissibility, and pathogenesis in a nonhuman primate model.

Effect of HIV-1 integrase resistance mutations when introduced into SIVmac239 on susceptibility to integrase strand transfer inhibitors.

UNLABELLED: Studies on the in vitro susceptibility of SIV to integrase strand transfer inhibitors (INSTIs) have been rare. In order to determine the susceptibility of SIVmac239 to INSTIs and characterize the genetic pathways that might lead to drug resistance, we inserted various integrase (IN) mutations that had been selected with HIV under drug pressure with raltegravir (RAL), elvitegravir (EVG), and dolutegravir (DTG) into the IN gene of SIV. We evaluated the effects of these mutations on SIV susceptibility to INSTIs and on viral infectivity. Sequence alignments of SIVmac239 IN with various HIV-1 isolates showed a high degree of homology and conservation of each of the catalytic triad and the key residues involved in drug resistance. Each of the G118R, Y143R, Q148R, R263K, and G140S/Q148R mutations, when introduced into SIV, impaired infectiousness and replication fitness compared to wild-type virus. Using TZM-bl cells, we demonstrated that the Q148R and N155H mutational pathways conferred resistance to EVG (36- and 62-fold, respectively), whereas R263K also displayed moderate resistance to EVG (12-fold). In contrast, Y143R, Q148R, and N155H all yielded low levels of resistance to RAL. The combination of G140S/Q148R conferred high-level resistance to both RAL and EVG (>300- and 286-fold, respectively). DTG remained fully effective against all site-directed mutants except G118R and R263K. Thus, HIV INSTI mutations, when inserted into SIV, resulted in a similar phenotype. These findings suggest that SIV and HIV may share similar resistance pathways profiles and that SIVmac239 could be a useful nonhuman primate model for studies of HIV resistance to INSTIs. IMPORTANCE: The goal of our project was to establish whether drug resistance against integrase inhibitors in SIV are likely to be the same as those responsible for drug resistance in HIV. Our data answer this question in the affirmative and show that SIV can probably serve as a good animal model for studies of INSTIs and as an early indicator for possible emergent mutations that may cause treatment failure. An SIV-primate model remains an invaluable tool for investigating questions related to the potential role of INSTIs in HIV therapy, transmission, and pathogenesis, and the present study will facilitate each of the above.

Early initiation of combination antiretroviral therapy in HIV-1-infected newborns can achieve sustained virologic suppression with low frequency of CD4+ T cells carrying HIV in peripheral blood.

BACKGROUND: A human immunodeficiency virus type 1 (HIV-1)-infected infant started on combination antiretroviral therapy (cART) at 30 hours of life was recently reported to have no detectable plasma viremia after discontinuing cART. The current study investigated the impact of early cART initiation on measures of HIV-1 reservoir size in HIV-1-infected children with sustained virologic suppression. METHODS: Children born to HIV-1-infected mothers and started on cART within 72 hours of birth at 3 Canadian centers were assessed. HIV serology, HIV-1-specific cell-mediated immune responses, plasma viremia, cell-associated HIV-1 DNA and RNA, presence of replication-competent HIV-1, and HLA genotype were determined for HIV-1-infected children with sustained virologic suppression. RESULTS: Of 136 cART-treated children, 12 were vertically infected (8.8%). In the 4 who achieved sustained virologic suppression, HIV serology, HIV-1-specific cell-mediated immune responses (Gag, Nef), and ultrasensitive viral load were negative. HIV-1 DNA was not detected in enriched CD4(+) T cells of the 4 children (<2.6 copies/10(6) CD4(+) T cells), whereas HIV-1 RNA was detected (19.5-130 copies/1.5 µg RNA). No virion-associated HIV-1 RNA was detected following mitogenic stimulation of peripheral blood CD4(+) T cells (5.4-8.0 million CD4(+) T cells) in these 4 children, but replication competent virus was detected by quantitative co-culture involving a higher number of cells in 1 of 2 children tested (0.1 infectious units/10(6) CD4(+) T cells). CONCLUSIONS: In perinatally HIV-1-infected newborns, initiation of cART within 72 hours of birth may significantly reduce the size of the HIV-1 reservoirs. Cessation of cART may be necessary to determine whether functional HIV cure can be achieved in such children.

A validated in-house assay for HIV drug resistance mutation surveillance from dried blood spot specimens.

Despite increasing scale-up of antiretroviral therapy (ART) coverage, challenges related to adherence and HIV drug resistance (HIVDR) remain. The high cost of HIVDR surveillance is a persistent challenge with implementation in resource-constrained settings. Dried blood spot (DBS) specimens have been demonstrated to be a feasible alternative to plasma or serum for HIVDR genotyping and are more suitable for lower resource settings. There is a need for affordable HIVDR genotyping assays which can amplify HIV-1 sequences from DBS specimens, particularly those with low viral loads, at a low cost. Here, we present an in-house assay capable of reliably amplifying HIV-1 protease and partial reverse transcriptase genes from DBS specimens, which covers the complete World Health Organization 2009 list of drug resistance mutations under surveillance. DBS specimens were prepared using whole blood spiked with HIV-1 at concentrations of 10,000, 5000, 1000, and 500 copies/mL (n=30 for each concentration). Specimens were tested in triplicate. A two-step approach was used consisting of cDNA synthesis followed by nested PCR. The limit of detection of the assay was calculated to be approximately 5000 (95% CI: 3200-10,700) copies/mL for the protease gene and 3600 (95% CI: 2200-10,000) copies/mL for reverse transcriptase. The assay was observed to be most sensitive with higher viral load specimens (97.8% [95% CI: 92.2-99.7]) for both protease and reverse transcriptase at 10,000 copies/mL with performance decreasing with the use of specimens with lower viral loads (46.7% [36.1-57.5] and 60.0% [49.1-70.2] at 500 copies/mL for protease and reverse transcriptase, respectively). Ultimately, this assay presents a promising opportunity for use in resource-constrained settings. Future work should involve validation under field conditions including sub-optimal storage conditions and preparation of DBS with fingerprick blood in order to accurately reflect real-world collection scenarios.

Differential Burden of HIV Among Adolescent Girls and Young Women by Places Associated With Sex Work: An Observational Study in Mombasa, Kenya.

BACKGROUND: The design of HIV prevention programs for adolescent girls and young women (AGYW) are informed by data on who is at highest risk and where they can be reached. Places (hotspots) associated with selling sex are an established outreach strategy for sex work (SW) programs but could be used to reach other AGYW at high risk. SETTING: This study took place in Mombasa, Kenya. METHODS: We conducted a cross-sectional, bio-behavioural survey among (N = 1193) sexually active AGYW aged 14-24 years recruited at hotspots. We compared HIV prevalence by subgroup (SW; transactional sex, TS; and non-transactional sex), stratified by hotspot type (venues and nonvenues). We examined whether associations between HIV prevalence and hotspot/subgroup remained after adjustment for individual-level risk factors, and estimated HIV prevalence ratio with and without adjustment for these individual-level factors. RESULTS: Overall HIV prevalence was 5.6%, 5.3% in venues and 7.3% in nonvenues. Overall SW HIV prevalence was 2-fold higher than among participants engaged in nontransactional sex. After adjusting for age and individual-level risk factors, HIV prevalence was 2.72 times higher among venue-based SWs (95% confidence interval: 1.56 to 4.85) and 2.11 times higher among nonvenue AGYW not engaged in SW (95% confidence interval: 0.97 to 4.30) compared with venue-based AGYW not engaged in SW. CONCLUSION: AGYW who sell sex remain at high risk of HIV across types of hotspots. The residual pattern of elevated HIV burden by AGWY subgroup and hotspot type suggests that unmeasured, network-level factors underscore differential risks. As such, hotspots constitute a "place" to reach AGYW at high risk of HIV.

Post-market surveillance of six COVID-19 point-of-care tests using pre-Omicron and Omicron SARS-CoV-2 variants.

Post-market surveillance of test performance is a critical function of public health agencies and clinical researchers that ensures tests maintaining diagnostic characteristics following their regulatory approval. Changes in product quality, manufacturing processes over time, or the evolution of new variants may impact product performance. During the COVID-19 pandemic, a plethora of point-of-care tests (POCTs) was released onto the Canadian market. This study evaluated the performance characteristics of several of the most widely distributed POCTs in Canada, including four rapid antigen tests (Abbott Panbio, BTNX Rapid Response, SD Biosensor, and Quidel QuickVue) and two molecular tests (Abbott ID NOW and Lucira Check IT). All tests were challenged with 149 SARS-CoV-2 clinical positives, including multiple variants up to and including Omicron XBB.1.5, as well as 29 clinical negatives. Results were stratified based on whether the isolate was Omicron or pre-Omicron as well as by reverse transcriptase quantitative PCR Ct value. The test performance of each POCT was consistent with the manufacturers' claims and showed no significant decline in clinical performance against any of the variants tested. These findings provide continued confidence in the results of these POCTs as they continue to be used to support decentralized COVID-19 testing. This work demonstrates the essential role of post-market surveillance in ensuring reliability in diagnostic tools.IMPORTANCEPost-market surveillance of diagnostic test performance is critical to ensure their reliability after regulatory approval. This is especially critical in the context of the COVID-19 pandemic as the use of point-of-care tests (POCTs) became widespread. Our study focused on four rapid antigen tests (Abbott Panbio, BTNX Rapid Response, SD Biosensor, and Quidel QuickVue) and two molecular tests (Abbott ID NOW and Lucira Check IT) that were widely distributed across Canada, assessing their performance using many SARS-CoV-2 variants, including up to Omicron subvariant XBB.1.5. Overall, we found no significant difference in performance against any variant, reinforcing confidence in their use. As concerns in test efficacy have been raised by news outlets, particularly regarding the BTNX Rapid Response, this work is even more timely and crucial. Our research offers insights into the performance of widely used COVID-19 POCTs but also highlights the necessity for post-market surveillance.

Validity of dried blood spot testing for sexually transmitted and blood-borne infections: A narrative systematic review.

Testing for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) using dried blood spot (DBS) specimens has been an integral part of bio-behavioural surveillance in Canada for almost two decades, though less is known regarding the use of DBS in surveillance of other sexually transmitted and blood-borne infections (STBBI). A systematic review was conducted using a peer-reviewed search strategy to assess the current evidence regarding the validity of STBBI testing using DBS specimens. Eligibility criteria included studies reporting use of DBS specimens for STBBI testing with either commercially available or "in-house" tests in populations 15 years of age or older. Studies reporting a measure of validity such as sensitivity, specificity, positive and negative predictive values were eligible for inclusion. Quality of studies and risk of bias were assessed using the QUADAS-2 tool. A total of 7,132 records were identified. Of these, 174 met the criteria for inclusion. Among the studies that reported validity measures, a substantial proportion demonstrated high sensitivity (≥90%) in 62.5% of cases (N = 334/534 sensitivity measurements), and high specificity (≥90%) was observed in 84.9% of instances (N = 383/451 specificity measurements). However, the quality of the studies varied greatly. Our findings support the validity of the use of DBS specimens in STBBI testing where sufficient evidence was available, but validity is highly dependent on thorough method development and validation.

Joint HIV and hepatitis C virus phylogenetic analyses signal network overlap among women engaged in sex work and men who purchase sex.

BACKGROUND: Transmission of HIV and hepatitis C virus (HCV) are heavily influenced by complex interactions within sexual or injecting networks where risk behaviors occur. In Ukraine, women engaged in sex work (WSW) and men who purchase sex (MWPS) are disproportionately affected by both viruses. The aim of our study was to the investigate the influence of underlying networks on transmission of HIV and HCV. METHODS: A cross-sectional integrated bio-behavioural survey was implemented among 560 WSW and 370 MWPS representative of sex work hotspots in Dnipro, Ukraine (December 2017 to March 2018). A portion of the HIV reverse transcriptase gene (n = 13; 62% WSW, 38% MWPS) and HCV NS5B gene (n = 46; 70% WSW, 30% MWPS) were sequenced from dried blood spot specimens. Tip-to-tip distances on phylogenetic trees were used to infer phylogenetic clusters for identifying potential transmission clusters. RESULTS: Phylogenetic analyses identified two HIV clusters containing four sequences (50% WSW; 50% MWPS) and 11 HCV clusters containing 31 sequences - the majority comprising infections in WSW (83.9%). Nearly half (45.4%) of HCV clusters contained at least one WSW with a history of injecting drugs. CONCLUSIONS: Joint analyses of HIV and HCV signal overlap in sex work and injecting networks in Ukraine, suggesting implications for the comprehensive coverage of prevention programs for WSW including harm reduction services. Conducting phylogenetic analyses with HCV may provide a more complete appraisal of underlying transmission networks than HIV alone, particularly in the context of high HIV treatment coverage yielding viral suppression.

Experimental infection of Cynomolgus Macaques (Macaca fascicularis) with human varicella-zoster virus.

Varicella-zoster virus (VZV) is a member of the alphaherpesvirus family and the causative agent of chickenpox and shingles. To determine the utility of cynomolgus macaques (Macaca fascicularis) as a nonhuman primate model to evaluate VZV-based simian immunodeficiency virus/human immunodeficiency virus (SIV/HIV) vaccines, we experimentally inoculated 10 animals with the parental Oka (Oka-P) strain of VZV derived from MeWo or Telo-RF cells. VZV DNA could be detected in the lungs as late as 4 days postinfection, with replicating virus detected by shell vial culture assay in one case. Infection did not result in any overt clinical symptoms but was characterized by humoral and cell-mediated immunity in a time frame and at a magnitude similar to those observed following VZV vaccination in humans. The cell line source of VZV inoculum influenced both the magnitude and polyfunctionality of cell-mediated immunity. Animals mounted a vigorous anamnestic antibody response following a second inoculation 12 weeks later. Inoculations resulted in transient increases in CD4(+) T-cell activation and proliferation, as well as a sustained increase in CD4(+) T cells coexpressing CCR5 and α4ß7 integrin. In contrast to previous failed attempts to successfully utilize attenuated VZV-Oka as an SIV vaccine vector in rhesus macaques due to suboptimal infectivity and cellular immunogenicity, the ability to infect cynomolgus macaques with Oka-P VZV should provide a valuable tool for evaluating VZV-vectored SIV/HIV vaccines.