Search

Introduction: The incidence of varicella in Canada has decreased by almost 99% since vaccination was introduced. However, variation in the timing and eligibility of vaccination programs across the country has resulted in some cohorts being under-vaccinated and therefore potentially susceptible to infection., Methods: We used nationally representative specimens from the Biobank of Statistics Canada's Canadian Health Measures Survey (CHMS) as well as residual specimens from Ontario collected between 2009-2014 to estimate population immunity across age-groups and geography, and identify any groups at increased risk of varicella infection., Results: The weighted proportion of specimens with antibody levels above the threshold of protection was 93.6% (95% CI: 92.4, 95.0). Protection was lowest among those aged 3-5 years (54.3%; 95% CI: 47.3, 61.4), but increased with age. Individuals born outside Canada had more than twice the odds of varicella susceptibility than those born in Canada (aOR: 2.7; 95% CI: 1.4, 5.0; p = 0.004). There were no differences by sex or geography within Canada, and there were no statistically significant differences when Ontario CHMS sera were compared to Ontario residual sera, apart from in participants aged 12-19 year age-group, for whom the CHMS estimate (91.2%; 95% CI: 86.7, 95.7) was significantly higher (p = 0.03) than that from residual specimens (85.9%, 95% CI: 81.1, 90.8)., Discussion: Varicella immunity in Canada is changing. Children appear to have low population immunity, placing them at greater risk of infection and at increased risk of severe disease as they age. Our results underscore the importance of performing periodic serosurveys to monitor further population immunity changes as the proportion of vaccine-eligible birth-cohorts increases, and to continually assess the risk of outbreaks., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Wright et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Introduction: Adolescent psychological wellbeing has been identified as an important public health priority and one of the major challenges facing young people. However, few studies have examined the wellbeing of Canadian adolescents nationwide in the past decade, and even fewer have focused specifically on immigrant adolescents. This study aims to investigate Canadian adolescent psychological wellbeing (PWB) via nationally representative data from the Programme for International Student Assessment (PISA) 2018. We explored what social and educational factors were critical in predicting Canadian adolescents' PWB, how adolescents from immigrant families differed from their non-immigrant peers in their wellbeing, and how adolescents' PWB was related to their academic performance., Methods: A total of 22,651 Grade 8 Canadian students who participated PISA 2018 were included in this study (mean age of 15; 49.9% female; 26% immigrant students). Mixed effects modeling was adopted for data analysis., Results: Our results showed that various social and educational factors were associated with adolescent PWB, but these relationships varied depending on which aspect of PWB was examined. Immigrant adolescents were shown to have higher levels of PWB when student attitudes toward immigrants were more positive. Additionally, most aspects of PWB were important for achievement performance., Discussion: It is important to develop healthy and supportive school and disciplinary climates that foster students' sense of belonging. To further support the PWB of immigrant adolescents, educators can implement activities and integrate learning materials on cultural diversity into curricula, encouraging students to develop positive attitudes toward immigrants. Our findings on the PWB of Canadian adolescents could provide valuable insights for other countries with diverse populations, particularly those with significant immigrant communities., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Liu, Maltais, Milner-Bolotin and Chachashvili-Bolotin.)

We evaluated the effectiveness of COVID-19 vaccines among South Asians living in Ontario, Canada compared to non-South Asians and compared the odds of symptomatic COVID-19 infection and related hospitalizations and deaths among non-vaccinated South Asians and non-South Asians. This was a test negative design study conducted in Ontario, Canada between December 14, 2020 and November 15, 2021. All eligible individuals >18 years with symptoms of COVID-19 were subdivided by ethnicity (South Asian vs other) and vaccination status (vaccinated versus not). The primary outcome was vaccine effectiveness as defined by COVID-19 infections, hospitalizations, and deaths, and secondary outcome was the odds of COVID-19 infections, hospitalizations, and death comparing non-vaccinated South Asians to non-vaccinated non-South Asians. 883,155 individuals were included. Among South Asians, two doses of COVID-19 vaccine prevented 93.8% (95% CI 93.2, 94.4) of COVID-19 infections and 97.5% (95% CI 95.2, 98.6) of hospitalizations and deaths. Among non-South Asians, vaccines prevented 86.6% (CI 86.3, 86.9) of COVID-19 infections and 93.1% (CI 92.2, 93.8) of hospitalizations and deaths. Non-vaccinated South Asians had higher odds of symptomatic SARS-CoV-2 infection compared to non-vaccinated non-South Asians (OR 2.35, 95% CI 2.3, 2.4), regardless of their immigration status. COVID-19 vaccines are effective in preventing infections, hospitalizations and deaths among South Asians living in Canada. The observation that non-vaccinated South Asians have higher odds of symptomatic COVID-19 infection warrants further investigation., Competing Interests: The authors have read the journal’s policy and have the following competing interests: SSA holds a Tier 1 Canada Research Chair in Ethnic Diversity and Cardiovascular Disease (#CRC-2017-00024), and the Michael G DeGroote Heart and Stroke Foundation of Canada Chair in Population Health Research outside of the submitted work. ML sits on vaccine advisory boards for Seqirus, Pfizer, Sanofi, Medicago, GSK, Merck, Novovax, and Janssen; is on the Data Safety Monitoring Board for CanSino Biologics, has received funding from Seqirus for a vaccine trial, is receiving in-kind supply of smallpox vaccines from Bavarian Nordic, and has provided expert testimony about vaccines outside of the submitted work. DMEB holds a Tier 2 Canada Research Chair in Aging and Immunity, sits on vaccine advisory boards for Pfizer and AstraZeneca, has received consulting fees/honoraria for Pfizer and AstraZeneca, and has provided expert testimony about vaccines outside of the submitted work. SB is the Director of the Centre for Vaccine Preventable Diseases (CVPD) at the University of Toronto outside of the submitted work. The CVPD receives operational support from a mix of funding sources, including through donations from pharmaceutical companies. A robust set of governance practices are in place to safeguard the academic freedom of the CVPD. BRS is funded by the University of Toronto as the Novo Nordisk Research Chair in Equitable Care of Diabetes and Related Conditions outside of the submitted work. DS holds the Heather M. Arthur Population Health Research Institute/Hamilton Health Sciences Chair in Inter-Professional Health Research and has received an honorarium from Diabetes Update 2023 for being an invited speaker and is a co-methods lead on the Diabetes Canada Clinical Practice Guidelines Steering Committee outside of the submitted work. GW has received grants from the Canadian Institutes of Health Research and the Hamilton Health Sciences Foundation outside of the submitted work. RJdS has received grants from the Canadian Institutes of Health Research, Canadian Foundation for Dietetic Research, Population Health Research Institute, and Hamilton Health Sciences Corporation; he has received consulting fees and travel honoraria from the World Health Organization’s Nutrition Guidelines Advisory Group; he is an Independent Director for the Helderleigh Foundation (Canada) and Co-Chair of a method working group for the ADA/EASD Precision Medicine in Diabetes group outside of the submitted work. SIB has received grants from the Canadian Institutes of Health Research and from the International Development Research Centre; he also served as a member of the US National Institute of Allergy and Infectious Diseases Data and Safety Monitoring Board for COVID-19 Preventive monoclonal antibodies trials outside of the submitted work. All other authors declare that they have no competing interests. This does not alter our adherence to PLOS policies on sharing data and materials. There are no patents, products in development or marketed products associated with this research to declare., (Copyright: © 2024 Chanchlani et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Measles is a highly infectious disease leading to high morbidity and mortality impacting people's lives and economies across the globe. The measles vaccine saves more lives than any other vaccine in the Essential Programme of Immunization and is also the most cost-effective vaccine, with an extremely high return on investment. This makes achieving measles elimination through vaccination a key child health intervention, particularly in low-income countries, where the overwhelming majority of measles deaths continue to occur. All countries and regions of the world have committed to achieving measles elimination, yet many have faced challenges securing political commitment at national and global levels and predictable, timely, and flexible support from global donors, and experienced setbacks during the COVID-19 pandemic. This has happened against a backdrop of stagnant measles vaccination coverage and declining enthusiasm for vertical programmes, culminating in a World Health Organization Strategic Advisory Group of Experts (WHO SAGE) review of the feasibility of measles eradication in 2019. Sustaining the elimination of measles long term is extremely difficult, and some countries have lost or nearly lost their measles elimination status in the face of ongoing importation of cases from neighbouring or closely connected countries in which elimination had been delayed. Thus, a widening equity gap in measles immunisation coverage creates challenges for all countries, not just those facing the greatest burden of measles morbidity and mortality. Delaying elimination of measles in some countries makes it cumulatively harder for all countries to succeed for three principal reasons: increased inequity in measles immunisation coverage makes outbreaks more likely to happen and to be larger; political will is very difficult to sustain; and immunity may wane to a point that transmission is re-established. New strategies are needed to support countries and regions in their vision for a world without measles, including ways to galvanise domestic, regional and global resources and ignite the political will that is essential to make the vision a reality.