COVID-19 mRNA vaccines induce robust levels of IgG but limited amounts of IgA within the oronasopharynx of young children.

Background: Understanding antibody responses to SARS-CoV-2 vaccination is crucial for refining COVID-19 immunization strategies. Generation of mucosal immune responses, including mucosal IgA, could be of potential benefit to vaccine efficacy, yet limited evidence exists regarding the production of mucosal antibodies following the administration of current mRNA vaccines to young children. Methods: We measured the levels of antibodies against SARS-CoV-2 from a cohort of children under 5 years of age undergoing SARS-CoV-2 mRNA vaccination (serially collected, matched serum and saliva samples, N=116) or on convenience samples of children under 5 years of age presenting to a pediatric emergency department (nasal swabs, N=103). Further, we assessed salivary and nasal samples for the ability to induce SARS-CoV-2 spike-mediated neutrophil extracellular traps (NET) formation. Results: Longitudinal analysis of post-vaccine responses in saliva revealed the induction of SARS-CoV-2 specific IgG but not IgA. Similarly, SARS-CoV-2 specific IgA was only observed in nasal samples obtained from previously infected children with or without vaccination, but not in vaccinated children without a history of infection. In addition, oronasopharyngeal samples obtained from children with prior infection were able to trigger enhanced spike-mediated NET formation, and IgA played a key role in driving this process. Conclusions: Despite the induction of specific IgG in the oronasal mucosa, current intramuscular vaccines have limited ability to generate mucosal IgA in young children. These results confirm the independence of mucosal IgA responses from systemic humoral responses following mRNA vaccination and suggest potential future vaccination strategies for enhancing mucosal protection in this young age group.

Crying out for help with root exudates: adaptive mechanisms by which stressed plants assemble health-promoting soil microbiomes.

Plants employ immunological and ecological strategies to resist biotic stress. Recent evidence suggests that plants adapt to biotic stress by changing their root exudation chemistry to assemble health-promoting microbiomes. This so-called 'cry-for-help' hypothesis provides a mechanistic explanation for previously characterized soil feedback responses to plant disease, such as the development of disease-suppressing soils upon successive cultivations of take all-infected wheat. Here, we divide the hypothesis into individual stages and evaluate the evidence for each component. We review how plant immune responses modify root exudation chemistry, as well as what impact this has on microbial activities, and the subsequent plant responses to these activities. Finally, we review the ecological relevance of the interaction, along with its translational potential for future crop protection strategies.

Canadian children's and youth's pedometer-determined steps/day, parent-reported TV watching time, and overweight/obesity: the CANPLAY Surveillance Study.

BACKGROUND: This study examines associations between pedometer-determined steps/day and parent-reported child's Body Mass Index (BMI) and time typically spent watching television between school and dinner. METHODS: Young people (aged 5-19 years) were recruited through their parents by random digit dialling and mailed a data collection package. Information on height and weight and time spent watching television between school and dinner on a typical school day was collected from parents. In total, 5949 boys and 5709 girls reported daily steps. BMI was categorized as overweight or obese using Cole's cut points. Participants wore pedometers for 7 days and logged daily steps. The odds of being overweight and obese by steps/day and parent-reported time spent television watching were estimated using logistic regression for complex samples. RESULTS: Girls had a lower median steps/day (10682 versus 11059 for boys) and also a narrower variation in steps/day (interquartile range, 4410 versus 5309 for boys). 11% of children aged 5-19 years were classified as obese; 17% of boys and girls were overweight. Both boys and girls watched, on average, < 40 minutes of television between school and dinner on school days. Adjusting for child's age and sex and parental education, the odds of a child being obese decreased by 20% for every extra 3000 steps/day and increased by 21% for every 30 minutes of television watching. There was no association of being overweight with steps/day, however the odds of being overweight increased by 8% for every 30 minutes of additional time spent watching television between school and dinner on a typical school day. DISCUSSION: Television viewing is the more prominent factor in terms of predicting overweight, and it contributes to obesity, but steps/day attenuates the association between television viewing and obesity, and therefore can be considered protective against obesity. In addition to replacing opportunities for active alternative behaviours, exposure to television might also impact body weight by promoting excess energy intake. CONCLUSIONS: In this large nationally representative sample, pedometer-determined steps/day was associated with reduced odds of being obese (but not overweight) whereas each parent-reported hour spent watching television between school and dinner increased the odds of both overweight and obesity.

Markers of sedentarism: the joint Canada/U.S. Survey of health.

BACKGROUND: The Joint Canada/United States Survey of Health (JCUSH) was a one-time collaborative survey undertaken by Statistics Canada and the National Center for Health Statistics. METHODS: This analysis provides country-, sex-, and age-specific comparative markers of adult obesity and sedentarism, defined as independent and collective groupings of self-reported leisure-time inactivity (<1.5 MET-hours/day), usual occupational sitting, and no/low active transportation (<1 hour/week). Logistic regression assessed the likelihood of sedentarism in U.S. vs. Canada, with and without adjusting for BMI-defined obesity categories: healthy weight (18.5 ≤ BMI <25 kg/m2; n = 3542), overweight (25 ≤ BMI < 30 kg/m2; n = 2,651), and obesity (BMI ≥ 30 kg/m2; n = 1470). RESULTS: Compared with Canadians, U.S. adults are 24% more likely to be overweight/ obese, 59% more likely to be inactive in leisure-time, 19% more likely to report no/low active transportation, and 39% more likely to collectively report all sedentarism markers, adjusting for sex and age. Focusing on obese individuals in both countries, obese U.S. residents were 90% more likely to be inactive during leisure-time, 41% more likely to report no/low active transportation, and 73% more likely to report all sedentarism markers. CONCLUSIONS: This ecological analysis sheds light on differential risks of obesity and sedentarism in these neighboring countries.

Descriptive epidemiology of youth pedometer-determined physical activity: CANPLAY.

PURPOSE: Objective measurement with body worn instrumentation is a preferred and increasingly common way to gather information about young people's physical activity. Measured samples have been typically small and recruited through schools. The purpose of this article was to present the descriptive epidemiology of children and youth pedometer-determined physical activity on the basis of a large national sample. METHODS: Children and youth (19,789) were recruited through random digit dialing. Participants were asked to wear the pedometer for seven consecutive days and to log daily steps. Of the 58% of participants who returned pedometer data, 95% wore the pedometer for at least 5 d. Daily step counts below 1000 or above 30,000 steps were truncated accordingly, and all values were included in the descriptive analysis. RESULTS: Boys and girls aged 5-19 yr took 12,259 and 10,906 steps per day, respectively. Daily steps were higher among boys than girls and declined by age group in a pattern consistent with that predicted by other smaller samples internationally. Weekday steps per day were generally higher than weekend day steps per day and varied by season. CONCLUSIONS: This study demonstrates the viability of using relatively inexpensive pedometers and methods for the surveillance of young people's physical activity. The resulting descriptive data provide key information regarding the population distribution of pedometer-determined physical activity that may be useful for identifying target groups for population strategies and other interventions.

Diagnosing streptococcal sore throat in adults: randomized controlled trial of in-office aids.

OBJECTIVE: To determine whether use of clinical decision rules or rapid streptococcal antigen detection tests (alone or in combination) can lower the number of unnecessary prescriptions for antibiotics for adults with acute sore throats. DESIGN: Four-arm randomized controlled trial. SETTING: Family practice offices in eastern Newfoundland. PARTICIPANTS: Forty urban and suburban family practitioners. INTERVENTIONS: Participants were randomly assigned to one of 4 arms (usual practice, decision rules only, rapid antigen test only, decision rules and antigen test combined), and each recruited successive adult patients presenting with acute sore throat as their main symptom. Following usual care or use of decision rules or rapid antigen tests or both (where applicable), physicians were to record what they prescribed for each patient. MAIN OUTCOME MEASURES: Prescribing rates and types of antibiotics prescribed. RESULTS: The prescribing rate using decision rules (55%) did not differ significantly from the rate using usual clinical practice (58%). Physicians using rapid antigen tests, both alone and with decision rules, had significantly lower prescribing rates (27% and 38%, respectively, both P < .001). CONCLUSION: Evidence-based clinical decision rules alone do not change family doctors' prescribing behaviour. Use of rapid antigen tests might allow physicians to persuade patients that negative results (and hence, viral infection) mean antibiotic therapy is not required.