Association of COVID-19 Government-Instituted Mask Mandates With Incidence of Mask Use Among Children in Alberta, Canada.

Importance: To help prevent the spread of SARS-CoV-2, government-instituted nonpharmaceutical interventions (eg, social distancing, mask use, isolating), a provincewide government-instituted mask mandate occurred on December 8, 2020, in Alberta, Canada, although some local jurisdictions implemented an earlier mask mandate. There remains a limited understanding of the association between government-implemented public health measures and individual health behaviors of children. Objective: To examine the association between government mask mandates and mask use among children in Alberta, Canada. Design, Setting, and Participants: A cohort of children from Alberta, Canada, was recruited to examine longitudinal SARS-CoV-2 serologic factors. Parents were prospectively asked about their child's mask use in public places every 3 months (5-point Likert scale: never to always) from August 14, 2020, to June 24, 2022. A multivariable logistic generalized estimating equation was used to examine government mandatory masking mandates and child mask use. Child mask use was operationalized into a single composite dichotomous outcome by grouping parents who reported their child often or always wore a mask vs those who reported their child never, rarely, or occasionally wore a mask. Exposures: The primary exposure variable was the government masking mandate (began on different dates in 2020). The secondary exposure variable was government private indoor and outdoor gathering restrictions. Main Outcomes and Measures: The primary outcome was parent report of child mask use. Results: A total of 939 children participated (467 female [49.7%]; mean [SD] age, 10.61 [1.6] years). The odds of parents' report of child mask use (often or always) was 18.3 times higher (95% CI, 5.7-58.6; P < .001; risk ratio, 1.7; 95% CI, 1.5-1.8; P < .001) with the mask mandate on compared with the mask mandate off. There was no significant change in mask use over the course of the mask mandate due to time. In contrast, each day with the mask mandate off was associated with a 1.6% decrease in mask use (odds ratio, 0.98; 95% CI, 0.98-0.99; P < .001). Conclusions and Relevance: The results of this study suggest that government-mandated mask use and providing the public with up-to-date health information (eg, case counts) is associated with increased parent-reported child mask use, while increasing time without a mask mandate is associated with decreased mask use.

Impact of Cesarean Delivery and Breastfeeding on Secretory Immunoglobulin A in the Infant Gut Is Mediated by Gut Microbiota and Metabolites.

How gut immunity in early life is shaped by birth in relation to delivery mode, intrapartum antibiotic prophylaxis (IAP) and labor remains undetermined. We aimed to address this gap with a study of secretory Immunoglobulin A (SIgA) in the infant gut that also tested SIgA-stimulating pathways mediated by gut microbiota and metabolites. Among 1017 Canadian full-term infants, gut microbiota of fecal samples collected at 3 and 12 months were profiled using 16S rRNA sequencing; C. difficile was quantified by qPCR; fecal metabolites and SIgA levels were measured by NMR and SIgA enzyme-linked immunosorbent assay, respectively. We assessed the putative causal relationships from birth events to gut microbiota and metabolites, and ultimately to SIgA, in statistical sequential mediation models, adjusted for maternal gravida status in 551 infants. As birth mode influences the ability to breastfeed, the statistical mediating role of breastfeeding status and milk metabolites was also evaluated. Relative to vaginal birth without maternal IAP, cesarean section (CS) after labor was associated with reduced infant gut SIgA levels at 3 months (6.27 vs. 4.85 mg/g feces, p < 0.05); this association was sequentially mediated through gut microbiota and metabolites of microbial or milk origin. Mediating gut microbiota included Enterobacteriaceae, C. difficile, and Streptococcus. The milk or microbial metabolites in CS-SIgA mediating pathways were galactose, fucose, GABA, choline, lactate, pyruvate and 1,2-propanediol. This cohort study documented the impact of birth on infant gut mucosal SIgA. It is the first to characterize gut microbe-metabolite mediated pathways for early-life SIgA maturation, pathways that require experimental verification.

Temporal trends in anaphylaxis ED visits over the last decade and the effect of COVID-19 pandemic on these trends.

BACKGROUND: Anaphylaxis is an acute systemic and potentially fatal allergic reaction. We evaluated trends in yearly rates of anaphylaxis in a pediatric Emergency Department (ED) in Montreal, Canada. METHODS: A prospective and retrospective recruitment process was used to find families of children who had presented with anaphylaxis at the Montreal Children's Hospital between April 2011 and April 2021. Using a uniform recruitment form, data were collected. Anaphylaxis patterns were compared to clinical triggers using descriptive analysis. RESULTS: Among 830,382 ED visits during the study period, 2726 (26% recruited prospectively) presented with anaphylaxis. The median age was 6 years (IQR: 0.2, 12.00), and 58.7% were males. The relative frequency of anaphylaxis cases doubled between 2011-2015, from 0.22% (95% CI, 0.19, 0.26) to 0.42 March 2020, the total absolute number of anaphylaxis cases and relative frequency declined by 24 cases per month (p < 0.05) and by 0.5% of ED visits (p < 0.05). CONCLUSIONS: The rate of anaphylaxis has changed over the years, representing modifications in food introduction strategies or lifestyle changes. The decrease in the frequency of anaphylaxis presenting to the ED during the COVID pandemic may reflect decreased accidental exposures with reduced social gatherings, closed school, and reluctance to present to ED.

Profound Dysregulation of T cell Homeostasis and Function in Patients With Severe COVID-19

PURPOSE OF THE STUDY: T cell lymphopenia is prevalent in severe coronavirus disease 2019 (COVID-19). This study evaluated associations with homeostatic and functional T cell responses in COVID-19 with the goal of identifying immunologic features of severe disease. STUDY POPULATION: Patients aged 18 years and older with symptomatic, real time-quantitative polymerase chain reaction confirmed SARS-CoV-2 (mild, n = 54;severe, n = 49) were recruited at 4 hospitals in the Canton of Zurich, Switzerland from April 2 to August 19, 2020, and a group of healthy controls recruited for comparison (n = 27). A subset (mild, n = 28;severe, n = 38, healthy, n = 22) had comprehensive T cell characterization. METHODS: In this prospective, observational, cross-sectional study, symptomatic participants with mild and severe COVID-19 and healthy controls were sampled at a single time point. Phenotypic and functional characteristics of T cells were evaluated using 40-parameter mass cytometry, flow cytometry, targeted proteomics, and functional assays. RESULTS: Compared with mild disease, severe COVID-19 was associated with T cell lymphopenia and redistribution of T cell populations, including loss of naïve and memory CD4+ and CD8+ T cells, skewing toward CD4+ T follicular helper cells and cytotoxic CD4+ T cells, and expansion of activated and exhausted T cells. Individuals with severe disease and T cell lymphopenia had signs of tissue migration, extensive T cell apoptosis, and impaired T cell responses to common viral antigens. Patients with severe disease also showed elevated interleukin-7 and increased T cell proliferation. Those sampled longest after symptom onset had higher T cell counts and improved antiviral T cell responses. CONCLUSIONS: Severe COVID-19 is characterized by extensive T cell dysfunction. Reduced naïve T cells and virus-specific memory T cell numbers are associated with severe disease and impaired T cell responses to viral antigens, particularly early in the disease. Increased T follicular helper cells may contribute to a robust antibody response often observed in COVID-19. T cell apoptosis is associated with lymphopenia and homeostatic T cell proliferation and T cell recovery in the later stages of disease.

Changes in food-related costs during the COVID-19 pandemic among families managing food allergy.

Background: The COVID-19 pandemic has affected the supply, cost, and demand for certain foods, but it is not clear how these changes have affected food-allergic households. Objective: To describe the changes in food-related costs that have followed COVID-19, as reported by higher- and lower-income households with a food-allergic member. Methods: Between May 1-June 30, 2020, Canadian households, with at least one food-allergic member, completed an online survey on food shopping and preparation habits before and during the COVID-19 pandemic. The sample was divided into binary groups, either higher or lower than the sample median income. Data were analyzed using descriptive statistics and multiple regression. Results: The sample was comprised of 102 participants (i.e., 51/ income group). The three most common food allergies amongst both groups were peanuts, tree nuts and milk. Since the start of the pandemic, both groups reported greater monthly direct grocery costs, although costs amongst the higher-income group were twice as high as the lower-income group ($212.86 vs. $98.89, respectively). Indirect food preparation costs were similarly elevated. Higher-income households with food procurement difficulties reported increased indirect shopping costs following the outbreak of COVID-19, whereas those without such difficulties reported decreased costs. Lower-income households with allergies to milk, wheat, or eggs (i.e., staple allergy) experienced a larger change in indirect food preparation costs following the outbreak of COVID-19 relative to those with other food allergies ($244.58 vs. -$20.28, respectively; p = 0.03). Conclusion: Both higher and lower income households with food allergy reported greater direct food costs and indirect food preparation costs following the COVID-19. Households with staple allergy and those with difficulties finding their typical food items were particularly affected.