COVID-19 vaccine reactogenicity among participants enrolled in the GENCOV study.

BACKGROUND: GENCOV is a prospective, observational cohort study of COVID-19-positive adults. Here, we characterize and compare side effects between COVID-19 vaccines and determine whether reactogenicity is exacerbated by prior SARS-CoV-2 infection. METHODS: Participants were recruited across Ontario, Canada. Participant-reported demographic and COVID-19 vaccination data were collected using a questionnaire. Multivariable logistic regression was performed to assess whether vaccine manufacturer, type, and previous SARS-CoV-2 infection are associated with reactogenicity. RESULTS: Responses were obtained from n = 554 participants. Tiredness and localized side effects were the most common reactions across vaccine doses. For most participants, side effects occurred and subsided within 1-2 days. Recipients of Moderna mRNA and AstraZeneca vector vaccines reported reactions more frequently compared to recipients of a Pfizer-BioNTech mRNA vaccine. Previous SARS-CoV-2 infection was independently associated with developing side effects. CONCLUSIONS: We provide evidence of relatively mild and short-lived reactions reported by participants who have received approved COVID-19 vaccines.

Characterizing Risk Factors for Hospitalization and Clinical Characteristics in a Cohort of COVID-19 Patients Enrolled in the GENCOV Study.

The GENCOV study aims to identify patient factors which affect COVID-19 severity and outcomes. Here, we aimed to evaluate patient characteristics, acute symptoms and their persistence, and associations with hospitalization. Participants were recruited at hospital sites across the Greater Toronto Area in Ontario, Canada. Patient-reported demographics, medical history, and COVID-19 symptoms and complications were collected through an intake survey. Regression analyses were performed to identify associations with outcomes including hospitalization and COVID-19 symptoms. In total, 966 responses were obtained from 1106 eligible participants (87% response rate) between November 2020 and May 2022. Increasing continuous age (aOR: 1.05 [95%CI: 1.01-1.08]) and BMI (aOR: 1.17 [95%CI: 1.10-1.24]), non-White/European ethnicity (aOR: 2.72 [95%CI: 1.22-6.05]), hypertension (aOR: 2.78 [95%CI: 1.22-6.34]), and infection by viral variants (aOR: 5.43 [95%CI: 1.45-20.34]) were identified as risk factors for hospitalization. Several symptoms including shortness of breath and fever were found to be more common among inpatients and tended to persist for longer durations following acute illness. Sex, age, ethnicity, BMI, vaccination status, viral strain, and underlying health conditions were associated with developing and having persistent symptoms. By improving our understanding of risk factors for severe COVID-19, our findings may guide COVID-19 patient management strategies by enabling more efficient clinical decision making.

Public knowledge of SARS-CoV-2 serological and viral lineage laboratory testing and result interpretation: A GENCOV study cross-sectional survey.

OBJECTIVES: Concepts related to SARS-CoV-2 laboratory testing and result interpretation can be challenging to understand. A cross-sectional survey of COVID-19 positive adults residing in Ontario, Canada was conducted to explore how well people understand SARS-CoV-2 laboratory tests and their associated results. DESIGN AND METHODS: Participants were recruited through fliers or by prospective recruitment of outpatients and hospitalized inpatients with COVID-19. Enrolled participants included consenting adults with a positive SARS-CoV-2 polymerase chain reaction test result. An 11-item questionnaire was developed by researchers, nurses, and physicians in the study team and was administered online between April 2021 to May 2022 upon enrolment into the study. RESULTS: Responses were obtained from 940 of 1106 eligible participants (85% participation rate). Most respondents understood 1) that antibody results should not influence adherence to social distancing measures (n = 602/888, 68%), 2) asymptomatic SARS-CoV-2 infection following test positivity (n = 698/888, 79%), 3) serological test sensitivity in relation to post-infection timeline (n = 540/891, 61%), and 4) limitations of experts' knowledge related to SARS-CoV-2 serology (n = 693/887, 78%). Conversely, respondents demonstrated challenges understanding 1) conflicting molecular and serological test results and their relationship with immune protection (n = 162/893, 18%) and 2) the impact of SARS-CoV-2 variants on vaccine effectiveness (n = 235/891, 26%). Analysis of responses stratified by sociodemographic variables identified that respondents who were either: 1) female, 2) more educated, 3) aged 18-44, 4) from a high-income household, or 5) healthcare workers responded expectedly more often. CONCLUSIONS: We have highlighted concepts related to SARS-CoV-2 laboratory tests and associated results which may be challenging to understand. The findings of this study enable us to identify 1) misconceptions related to various SARS-CoV-2 test results, 2) groups of individuals at risk, and 3) strategies to improve people's understanding of their test results.

Genome screening, reporting, and genetic counseling for healthy populations.

Rapid advancements of genome sequencing (GS) technologies have enhanced our understanding of the relationship between genes and human disease. To incorporate genomic information into the practice of medicine, new processes for the analysis, reporting, and communication of GS data are needed. Blood samples were collected from adults with a PCR-confirmed SARS-CoV-2 (COVID-19) diagnosis (target N = 1500). GS was performed. Data were filtered and analyzed using custom pipelines and gene panels. We developed unique patient-facing materials, including an online intake survey, group counseling presentation, and consultation letters in addition to a comprehensive GS report. The final report includes results generated from GS data: (1) monogenic disease risks; (2) carrier status; (3) pharmacogenomic variants; (4) polygenic risk scores for common conditions; (5) HLA genotype; (6) genetic ancestry; (7) blood group; and, (8) COVID-19 viral lineage. Participants complete pre-test genetic counseling and confirm preferences for secondary findings before receiving results. Counseling and referrals are initiated for clinically significant findings. We developed a genetic counseling, reporting, and return of results framework that integrates GS information across multiple areas of human health, presenting possibilities for the clinical application of comprehensive GS data in healthy individuals.

Implementation of serological and molecular tools to inform COVID-19 patient management: protocol for the GENCOV prospective cohort study.

INTRODUCTION: There is considerable variability in symptoms and severity of COVID-19 among patients infected by the SARS-CoV-2 virus. Linking host and virus genome sequence information to antibody response and biological information may identify patient or viral characteristics associated with poor and favourable outcomes. This study aims to (1) identify characteristics of the antibody response that result in maintained immune response and better outcomes, (2) determine the impact of genetic differences on infection severity and immune response, (3) determine the impact of viral lineage on antibody response and patient outcomes and (4) evaluate patient-reported outcomes of receiving host genome, antibody and viral lineage results. METHODS AND ANALYSIS: A prospective, observational cohort study is being conducted among adult patients with COVID-19 in the Greater Toronto Area. Blood samples are collected at baseline (during infection) and 1, 6 and 12 months after diagnosis. Serial antibody titres, isotype, antigen target and viral neutralisation will be assessed. Clinical data will be collected from chart reviews and patient surveys. Host genomes and T-cell and B-cell receptors will be sequenced. Viral genomes will be sequenced to identify viral lineage. Regression models will be used to test associations between antibody response, physiological response, genetic markers and patient outcomes. Pathogenic genomic variants related to disease severity, or negative outcomes will be identified and genome wide association will be conducted. Immune repertoire diversity during infection will be correlated with severity of COVID-19 symptoms and human leucocyte antigen-type associated with SARS-CoV-2 infection. Participants can learn their genome sequencing, antibody and viral sequencing results; patient-reported outcomes of receiving this information will be assessed through surveys and qualitative interviews. ETHICS AND DISSEMINATION: This study was approved by Clinical Trials Ontario Streamlined Ethics Review System (CTO Project ID: 3302) and the research ethics boards at participating hospitals. Study findings will be disseminated through peer-reviewed publications, conference presentations and end-users.

Pregnancy-induced changes in the long-term pharmacokinetics of 1.1 mg vs. 5 mg folic acid: a randomized clinical trial.

The objective of this randomized clinical trial was to compare steady-state gestational RBC and plasma folate concentrations in pregnant women supplementing daily with 1.1 mg (regular dose) vs. 5 mg (high dose) folic acid. Thirty-seven pregnant women, who were not previously taking folic acid, were enrolled in this open-label, 2-arm, randomized clinical trial after informed consent. Participants were randomly assigned either 1.1 or 5 mg of folic acid-containing prenatals until gestational age (g.a.) 30 weeks. Plasma and RBC folate concentrations were measured at baseline, g.a.6 weeks, g.a.12 weeks, and g.a.30 weeks using a chemiluminescent immunoassay. Results showed sustained significant increase in RBC folate in the 5 mg group between g.a.6 weeks and g.a.30 weeks (P < 0.001), and between g.a.12 weeks and g.a.30 weeks (P < 0.01), whereas a significant increase in RBC folate concentrations was observed in the 1.1 mg group only between g.a.12 weeks to g.a.30 weeks (P < 0.05). Plasma folate increased in both groups from baseline to g.a.6 weeks, and then decreased between g.a.6 weeks and g.a.30 weeks, but this was not statistically significant. Plasma concentrations at g.a.30 weeks in both groups were comparable to their respective baseline concentrations. Thus, physiological changes in pregnancy alter long-term folate pharmacokinetics. Despite supplementation over an extended period of time, steady-state does not seem to be achieved in either dose group within our study.

The impact of not having a ductus arteriosus on clinical outcomes in foetuses diagnosed with tetralogy of Fallot.

BACKGROUND: Foetuses with simple tetralogy of Fallot almost universally have a patent ductus arteriosus. Two recently identified cases had an absent patent ductus arteriosus, requiring emergent intervention at birth. The objective of this study was to determine whether foetuses diagnosed with tetralogy of Fallot and no patent ductus arteriosus have poorer outcomes compared with those with tetralogy of Fallot+patent ductus arteriosus. METHODS: All foetal cases of tetralogy of Fallot between January, 2000 and 2012 were retrospectively identified from The Hospital for Sick Children (Toronto, Canada) database. Cases - tetralogy of Fallot+no patent ductus arteriosus confirmed on postnatal echo - and controls - tetralogy of Fallot+patent ductus arteriosus, matched for gestational age - were identified from prenatal records, and both clinical and echocardiographic data were reviewed. Optimal outcome was defined as valve-sparing repair with no residual lesions. Student's t-tests and Fisher's exact χ2 were used to compare groups. RESULTS: n=115 foetuses were diagnosed with tetralogy of Fallot: 11 (9%) had no patent ductus arteriosus, and were matched to 22 controls - mean gestational age at diagnosis 23.2±4.2 weeks, 23.4±6.6 weeks, respectively. Cases had a higher proportion of right aortic arches (64% versus 14%, p<0.001). Foetal and postnatal echocardiographic data did not reveal significant differences in branch pulmonary artery sizes, pulmonary valve sizes, or ventricular function. No differences were identified for cyanosis at birth (2/10 versus 7/20, p=0.67), or catheter intervention (5/10 versus 4/22, p=0.12). Optimal outcome rates were similar between cases and controls (4/11 (36%) versus 5/21 (24%), p=0.68). CONCLUSIONS: The patent ductus arteriosus does not appear to have an impact on clinical outcome in foetuses with tetralogy of Fallot.

Folate Intake, MTHFR Polymorphisms, and the Risk of Colorectal Cancer: A Systematic Review and Meta-Analysis.

Background. The objective was to determine whether relationships exist between the methylene-tetrahydrofolate reductase (MTHFR) polymorphisms and risk of colorectal cancer (CRC) and examine whether the risk is modified by level of folate intake. Methods. MEDLINE, Embase, and SCOPUS were searched to May 2012 using the terms "folic acid," "folate," "colorectal cancer," "methylenetetrahydrofolate reductase," "MTHFR." Observational studies were included which (1) assessed the risk of CRC for each polymorphism and/or (2) had defined levels of folate intake for each polymorphism and assessed the risk of CRC. Results. From 910 references, 67 studies met our criteria; hand searching yielded 10 studies. The summary risk estimate comparing the 677CT versus CC genotype was 1.02 (95% CI 0.95-1.10) and for 677TT versus CC was 0.88 (95% CI 0.80-0.96) both with heterogeneity. The summary risk estimates for A1298C polymorphisms suggested no reduced risk. The summary risk estimate for high versus low total folate for the 677CC genotype was 0.70 (95% CI 0.56-0.89) and the 677TT genotype 0.63 (95% CI 0.41-0.97). Conclusion. These results suggest that the 677TT genotype is associated with a reduced risk of developing CRC, under conditions of high total folate intake, and this associated risk remains reduced for both MTHFR 677 CC and TT genotypes.

Dosage requirements for periconceptional folic acid supplementation: accounting for BMI and lean body weight.

OBJECTIVE: To determine folic acid dosage requirements for individuals across a broad range of BMI values, using dose per kilogram lean body weight (LBW) as a primary predictor of systemic exposure. Steady-state folate concentrations of ≥ 15.9 nmol/L were assumed to be sufficient for reducing the risk for neural tube defects in the general population. METHODS: Data from a recent study of single-dose folic acid pharmacokinetics among 12 obese and 12 non-obese women of childbearing age were analyzed to determine expected steady-state concentrations. The mean folic acid dose per kilogram LBW that achieved serum folate concentrations of ≥ 15.9 nmol/L was applied to a broad range of BMI values to evaluate daily dose requirements. RESULTS: Modest differences in folic acid requirements were noted for individuals among the non-obese, overweight, and obese categories. The current supplementation guidelines suggesting a daily dose of 0.4 mg appear to satisfy the needs of women at even the upper extremes of obesity. However, because even with appropriate folate supplementation obese women have an increased risk of neural tube defects, and they may benefit from higher intake and higher serum concentrations of folic acid. CONCLUSION: Current guidelines recommend an adequate folic acid dose for obese women of childbearing age. Thus, it is unlikely that folate deficiency is associated with the elevated risk for neural tube defects in this population.

A flexible microfluidic processor for molecular biology: application to microarray sample preparation.

We describe a programmable microfluidic system with onboard pumps and valves that has the ability to process reaction volumes in the sub-microlitre to hundred microlitre range. The flexibility of the architecture is demonstrated with a commercial molecular biology protocol for mRNA amplification, implemented without significant modification. The performance of the microchip system is compared to conventional bench processing at each stage of the multistep protocol, and DNA microarrays are used to assess the quality and performance of bench- and microchip-amplified RNA. The results show that the microchip system reactions are similar to bench control reactions at each step, and that the microchip- and bench-derived amplified RNAs are virtually indistinguishable in differential microarray analyses.

A comparison of folic acid pharmacokinetics in obese and nonobese women of childbearing age.

BACKGROUND: Although maternal folate deficiency during the periconceptional period represents a major risk factor for neural tube defects, obesity has been recognized as an additional risk factor. Studies have identified an increased risk for neural tube defect-affected births among obese mothers even after adjusting for folic acid supplementation. However, although folic acid intake may have been at the recommended dose in these samples, blood folate concentrations were not monitored to ensure that protective levels were reached. Hence, there is a need to compare folic acid pharmacokinetics in obese and nonobese women of childbearing age. METHODS: Healthy obese (n=12) and nonobese (n=12) women of childbearing age volunteered to participate. Each obese participant was matched to a nonobese participant and assigned an equivalent dose of folic acid per kilogram body weight. Folic acid was orally administered after a 6-hour fast, and blood samples were taken over a 10-hour period to evaluate pharmacokinetic parameters. RESULTS: Area under the time-concentration curve (AUC) was found to be significantly higher in the obese group (P=0.008). Defining AUC as a function of dose per kilogram lean body weight (LBW) was found to be a stronger predictor than dose per kilogram total body weight (r=0.90 and 0.76, respectively). CONCLUSIONS: This indicates that the body tightly controls systemic exposure to folic acid, with 90% of the variability in AUC controlled by the dose per kilogram LBW. Periconceptional supplementation recommendations may need to be adjusted to account for LBW differences in the obese population.

Folate intake and the risk of colorectal cancer: a systematic review and meta-analysis.

INTRODUCTION: Folic acid fortification and supplementation to prevent neural tube defects has led to concerns regarding increased risk of colorectal cancer. The results of existing studies have been inconclusive. The purpose was to examine the relationship between level of folate intake and the incidence of colorectal cancer. METHODS: A systematic review and meta analysis were conducted. MEDLINE, Embase, and SCOPUS were searched from inception to October 2009 with the following search terms "folic acid," "folate", "colorectal cancer," "colon neoplasms," rectal neoplasms." Observational studies in adult populations were included that defined levels of folate intake and incidence of colorectal cancer. RESULT: Out of 6427 references, 27 studies met our inclusion criteria. The summary risk estimate for case control studies comparing high versus low total folate intake was 0.85 (CI 95% 0.74-0.99) with no significant heterogeneity among studies. Similarly, for cohort studies, the resulting summary risk estimate for high versus low dietary folate intake was 0.92 (CI 95% 0.81-1.05) with no significant heterogeneity. However, defining what represents a higher intake of folic acid is difficult as there is variability in the upper limit of folic acid intake used in the studies. DISCUSSION: These results suggest that higher folate intake levels offer a reduction in one of the perceived risks associated with developing colorectal cancer. These data can serve to help reassure women planning a pregnancy to increase folic intake during the preconception period to levels sufficient to prevent neural tube defects.

Microfluidic purification and preconcentration of mRNA by flow-through polymeric monolith.

Efficient and rapid isolation of mRNA is important in the field of genomics as well as in the clinical and pharmaceutical arena. We have developed UV-initiated methacrylate-based porous polymer monoliths (PPM) for microfluidic trapping and concentration of eukaryotic mRNA. PPM are cast-to-shape and are tunable for functionalization using a variety of amine-terminated molecules. Efficient isolation of eukaryotic mRNA from total RNA was first mathematically modeled and then achieved using PPM in capillaries. Purification protocols using oligo dT's, locked nucleic acid substituted dT's, and tetramethylammonium chloride salts were characterized. mRNA yield and purity were compared with mRNA isolated by commercial kits with statistically equivalent yields and purities (determined by qPCR ratio of 18s rRNA and Gusb mRNA markers). Even after extracting 16 microg of mRNA from 315 microg of total RNA, the 0.4-microL volume monolith showed no signs of saturation. Elution volumes were below 20 microL with concentrations up to 1 microg/microL. In addition, the polymeric material exhibited exceptional stability in a range of conditions (pH, temperature, dryness) and was stable for a period of months. All of these characteristics make porous polymer monoliths good candidates for potential microfluidic sample preconcentrators and purifiers.