Publications by authors named "Ellen Chan"
Importance: As a result of low numbers of pediatric cases early in the COVID-19 pandemic, pediatric household transmission of SARS-CoV-2 remains an understudied topic.
Objective: To determine whether there are differences in the odds of household transmission by younger children compared with older children.
Design, Setting, And Participants: This population-based cohort study took place between June 1 and December 31, 2020, in Ontario, Canada.
Introduction: HIV-infected individuals have evidence of intestinal microbial translocation which is associated with immune activation and unfavorable clinical outcomes. Rifaximin, a non-absorbable antibiotic which reduces microbial translocation in other disease states, was shown to have a marginal beneficial effect on microbial translocation, T-cell activation, and inflammation in a multisite randomized trial (ACTG A5286; NCT01466595) of HIV-infected persons with poor immunologic recovery receiving ART. Here, we report analysis of the rectal microbiome changes associated with that trial.
View Article and Find Full Text PDFBackground: Vitamin D (VitD) and calcium (Ca) supplementation attenuates antiretroviral therapy (ART)-associated bone loss, but it is unclear whether this effect is mediated through immunomodulation.
Methods: In this exploratory analysis of A5280, a 48-week, randomized, double-blind, placebo-controlled study of VitD/Ca supplementation with ART initiation, we characterized lymphocyte phenotypes and receptor activator of nuclear factor kappa-B ligand (RANKL) expression by median fluorescence intensity (MFI) at baseline and 48 weeks. Changes were evaluated within and between treatment groups by Wilcoxon signed rank and rank sum tests, respectively.
Background: Dipeptidyl peptidase-4 (DPP-4) inhibitors have pleotropic anti-inflammatory and immune regulatory effects in addition to glucoregulation. We evaluated inflammation and immune markers in suppressed human immunodeficiency virus (HIV) infection during treatment with the DPP-4 inhibitor sitagliptin.
Methods: Virologically suppressed adults with HIV without diabetes on stable antiretroviral therapy (ART) with ≥100/μL CD4 cells were randomized to 16 weeks of sitagliptin 100 mg/day vs placebo in a multicenter trial.
Vitamin D Supplementation Does Not Affect Metabolic Changes Seen With ART Initiation.
Open Forum Infect Dis
December 2017
Background: Insulin resistance and lipid changes are common after antiretroviral therapy (ART) initiation. Observational studies suggest that vitamin D supplementation reduces the risk of developing diabetes and improves lipid profiles.
Methods: This 48-week prospective, randomized, double-blind, placebo-controlled study evaluated high-dose vitamin D3 (4000 IU daily) plus calcium supplementation (1000 mg calcium carbonate daily) in HIV-infected participants initiating ART with efavirenz/emtricitabine/tenofovir (EFV/FTC/TDF).
Objective: The aim of this article is to describe the Systems Addressing Frail Elder (SAFE) Care model, features of the interprofessional team and reengineered workflow, and details of the intervention.
Background: Older inpatients are vulnerable to adverse events related to frailty. SAFE Care, an interprofessional team-based program, was developed and evaluated in a cluster randomized controlled trial (C-RCT).
Objectives: Some studies suggest that bioavailable 25-dihydroxyvitamin D [25-(OH)D] is more accurate than total 25-(OH)D as an assessment of vitamin D (VitD) status in black individuals. We hypothesized that increases in bioavailable 25-(OH)D would correlate better with improvement in bone outcomes among black HIV-infected adults.
Design: This is a secondary analysis of AIDS Clinical Trials Group A5280, a randomized, double-blind study of VitD3 and calcium supplementation in HIV-infected participants initiating antiretroviral therapy.
Background: Persistent immune activation and inflammation in virologically suppressed human immunodeficiency virus (HIV) infection are linked to excess cardiovascular risk.
Objective: To evaluate atorvastatin as a strategy to reduce cardiovascular risk.
Methods: A5275 was a multicenter, prospective, randomized, double-blind, placebo-controlled, cross-over pilot study of atorvastatin (10 mg/day for 4 weeks then 20 mg/day for 16 weeks) with a planned enrollment of 97 HIV-infected participants ≥18 years old, receiving boosted protease inhibitor-based antiretroviral therapy for ≥6 months, with plasma HIV-1 RNAs below limits of quantification ≥180 days, and fasting low-density lipoprotein (LDL) cholesterol ≥70 and <130 mg/dL.
An Evaluation of Provincial Infectious Disease Surveillance Reports in Ontario.
J Public Health Manag Pract
September 2018
Context: Public Health Ontario (PHO) publishes various infectious disease surveillance reports, but none have yet been formally evaluated.
Objective: PHO evaluated its monthly and annual infectious disease surveillance reports to assess public health stakeholders' current perception of the products and to develop recommendations for improving future products.
Design: An evaluation consisting of an online survey and a review of public Web sites of other jurisdictions with similar annual reports.
Objective: The objective was to determine whether maraviroc (MVC) has unique neurocognitive benefits in the context of initial antiretroviral therapy (ART).
Design: Randomized, double-blind, placebo-controlled, 48-week trial.
Setting: Participants were enrolled in US AIDS Clinical Trials Group clinical trial sites.
Objective: Studies exploring the immunologic effects of maraviroc (MVC) have produced mixed results; hence, it remains unclear whether MVC has unique immunologic effects in comparison with other antiretroviral drugs. We sought to determine whether MVC has differential effects compared with tenofovir disoproxil fumarate (TDF) during initial antiretroviral therapy.
Design: Prospective study in AIDS Clinical Trials Group A5303, a double-blind, placebo-controlled trial (N = 262) of MVC vs.
Background: Extended hospital stays and complications are common among older adults and may lead to morbidity and loss of independence. Specialized geriatric units have been shown to improve outcomes but, with the growing numbers of older adults, may be difficult to scale to meet needs.
Purpose: The purpose was to evaluate a quality improvement initiative that redesigned unit-based workflow and trained interprofessional teams on general medical/surgical units to create care plans for vulnerable older adults using principles of comprehensive geriatric assessment and team management.
Background: Intrapartum single-dose nevirapine (sdNVP) reduces HIV-1 perinatal transmission but selects NVP resistance among mothers and infants. We evaluated the frequency of antiretroviral resistance among infants with intrauterine HIV-1 infection exposed to sdNVP and maternal antenatal or breastfeeding antiretroviral therapy.
Methods: This analysis included 429 infants from sub-Saharan Africa, India and Haiti whose 422 mothers received sdNVP plus maternal study treatment.
Background: Antiretroviral therapy initiation for HIV-1 infection is associated with 2% to 6% loss of bone mineral density (BMD).
Objective: To evaluate the effect of vitamin D3 plus calcium supplementation on bone loss associated with antiretroviral therapy initiation.
Design: 48-week prospective, randomized, double-blind, placebo-controlled study.
Background: There is a need to prevent or minimize bone loss associated with antiretroviral treatment (ART) initiation. We compared maraviroc (MVC)- to tenofovir disoproxil fumarate (TDF)-containing ART.
Methods: This was a double-blind, placebo-controlled trial.
Background: Rifaximin, a nonabsorbable antibiotic that decreases lipopolysaccharide (LPS) in cirrhotics, may decrease the elevated levels of microbial translocation, T-cell activation and inflammation in human immunodeficiency virus (HIV)-positive immune nonresponders to antiretroviral therapy (ART).
Methods: HIV-positive adults receiving ART for ≥96 weeks with undetectable viremia for ≥48 weeks and CD4(+) T-cell counts <350 cells/mm(3) were randomized 2:1 to rifaximin versus no study treatment for 4 weeks. T-cell activation, LPS, and soluble CD14 were measured at baseline and at weeks 2, 4, and 8.
Background: The dynamics of CD4+ T cell reconstitution and changes in immune activation and inflammation in HIV-1 disease following initiation of antiretroviral therapy (ART) are incompletely defined and their underlying mechanisms poorly understood.
Methods: Thirty-nine treatment-naïve patients were treated with raltegravir, tenofovir DF and emtricitabine. Immunologic and inflammatory indices were examined in persons with sustained virologic control during 48 weeks of therapy.
Background: Chlamydia (Chlamydia trachomatis) is the most commonly diagnosed sexually transmissible infection (STI) in Singapore, with rising incidence.
Method: Random sampling was performed on all chlamydia-positive samples collected from female patients who attended a women's clinic from January 2010 to December 2010. Some 250 electronic medical records were analysed.
Development and maintenance of a controlled vocabulary via an electronic collaborative platform.
Stud Health Technol Inform
April 2015
The development of electronic health records and clinical information systems has been progressing at a quickened pace in recent years. With such change, the use of standard vocabulary has aroused much interest. However, classification code sets are developed for their distinctive purposes, no single vocabulary set could satisfy the needs of all specialties; moreover, local customization would be inevitable.
View Article and Find Full Text PDFBackground: Clinical studies have shown faster disease progression and stronger immune activation in human immunodeficiency virus (HIV)-1-infected females when compared with males for the same level of HIV-1 replication. Here we determine whether the elevated levels of HIV-1-induced interferon-alpha (IFN-α) production observed in females are associated with higher interferon-stimulated gene (ISG) expression levels in T cells, hence suggesting type-I IFN as a mechanism for the higher HIV-1-associated immune activation observed.
Methods: T-cell and dendritic cell populations were isolated from treatment-naive chronically HIV-1-infected individuals enrolled in the Adult Clinical Trials Group 384 by fluorescence-activated cell sorting.
Objective: Nevirapine is metabolized by cytochrome P450 (CYP) 2B6 and CYP3A4. We characterized relationships between clinical parameters, human genetics, pharmacokinetics, and human immunodeficiency virus type 1 (HIV-1) drug resistance mutations in pregnant women following single-dose intrapartum nevirapine.
Methods: In AIDS Clinical Trials Group study A5207, women received nevirapine at onset of labor and were randomly assigned to receive lamivudine/zidovudine, emtricitabine/tenofovir, or lopinavir/ritonavir for 7 or 21 days.
Background: Nevirapine (NVP) resistance emerges in up to 70% of women exposed to single-dose (sd) NVP for prevention of mother-to-child transmission of human immunodeficiency virus (HIV).
Methods: HIV-infected pregnant women were randomized to receive sdNVP and either zidovudine/lamivudine (3TC), tenofovir/emtricitabine (FTC), or lopinavir/ritonavir for either 7 or 21 days. The primary endpoint was the emergence of new NVP resistance mutations as detected by standard population genotype at 2 and 6 weeks after treatment.
Background: HIV-1-infected individuals with plasma RNA<50 copies/ml on antiretroviral therapy (ART) may have residual, low-level viraemia detectable by PCR assays that are able to detect a single copy of viral RNA (single-copy assay [SCA]). The clinical predictors of residual viraemia in patients on long-term suppressive ART are not yet fully understood.
Methods: We evaluated factors associated with residual viraemia in patients on suppressive ART who underwent screening for a raltegravir intensification trial (ACTG A5244).
Background: Controversy continues regarding the extent of ongoing viral replication in HIV-1-infected patients on effective antiretroviral therapy (ART). Adding an additional potent agent, such as raltegravir, to effective ART in patients with low-level residual viremia may reveal whether there is ongoing HIV-1 replication.
Methods: We previously reported the outcome of a randomized placebo-controlled study of raltegravir intensification in patients on ART with HIV-1 RNA <50 copies per milliliter that showed no effect on residual viremia measured by single copy assay.
Objectives: The present study objectively examined the possible difference in vocal characteristics associated with English and Cantonese produced by proficient Cantonese-English bilingual speakers.
Subjects And Methods: Forty native speakers of Cantonese (20 males and 20 females) who were proficient in Cantonese and English participated in the study. An array of acoustical parameters, including fundamental frequency (F0) values and first spectral peak (FSP), mean spectral energy (MSE), and spectral tilt (ST) extracted from long-term average speech spectra were obtained from connected speech samples produced in Cantonese and English by the bilingual speakers.