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While Canada has had relatively high vaccination rates against COVID-19, specifically during earlier waves of the pandemic, vaccine hesitancy has continued to serve as a significant barrier to adequate protection against the virus and, more recently, booster vaccine uptake. This paper explores the processes underlying Canadians' perceptions of COVID-19 vaccines and their decisions to take or refuse them, as well as how public policy and health messaging about vaccination has influenced vaccination attitudes and behaviors. Our focus group interviews with 18 vaccinated and unvaccinated adult Canadians conducted during October 2021 reveal that, in some respects, COVID-19 vaccine hesitancy conforms to prior knowledge about some of the factors that affect vaccine attitudes (e.g., the influence of known medical providers) but deviates from current theoretical frameworks regarding general vaccine hesitancy. Specifically, these frameworks emphasize a lack of scientific knowledge and literacy ("knowledge deficit" accounts) or individuals' inability to incorporate rational risk perceptions into initial emotional responses to vaccines ("emotionality/irrationality" accounts). In contrast to the knowledge deficit account, we find that expressions of COVID-19 vaccine hesitancy were most frequently associated with an information surplus or inability to prioritize information from multiple and often contradictory sources. Furthermore, top-down pro-vaccination messaging often triggered significant pushback against what participants perceived as moral shaming of the unvaccinated. Our findings demonstrate the necessity for a new framework to understand and address vaccine hesitancy. A better theoretical account of vaccine hesitancy has important implications for future vaccination efforts, specifically within the context of new variants and low booster vaccination rates in Canada. [ABSTRACT FROM AUTHOR]

• 43 % of WHO member states have school vaccine mandates, but policy details vary. • Some mandates have begun to include education components for non-vaccinating parents/guardians. • Currently, education components are used only in Canada and the U.S.; most are online modules. • Evidence suggests in-person counseling is associated with decreased non-medical exemptions. • Additional research, especially on online module education components, is required. School vaccine mandates (SVMs) are population health interventions that require monitoring and communicating about vaccination of school-aged children, with an aim of controlling infectious disease outbreaks. While 43 % of World Health Organization member states report having some sort of SVM, their details vary. A newer element of some SVMs is an "education component" requiring compulsory information, education, or counseling of parents/guardians who decline to vaccinate their children for non-medical reasons. This environmental scan sought, mapped, and synthesized evidence on the existence, format, and impacts of education components of SVMs in 18 affluent Organization for Economic Co-operation and Development comparator countries. We found current SVMs in nine of the 18 comparator countries, but education components to those SVMs only in Canada (n = 2) and the U.S. (n = 9), where such policies were made at the provincial/state level. The earliest was implemented in 2011 and most recent has not yet been implemented. Education components were used as requirements for obtaining non-medical exemptions from SVMs, and involved either an informational paper to be read and signed, a counseling or information session from a health professional (public health worker or licensed provider such as family doctor), or an online module to be completed. Peer-reviewed research on in-person sessions suggests association with at least short-term increased vaccine uptake and reduction of non-medical exemptions. Available data on online module education components suggests similar impacts, but research to date is limited. SVMs with educational components are uncommon but have been increasing since 2011. The details of these education components vary, although topics covered in online modules are relatively consistent. Evidence to date suggests at least short-term reduction in non-medical exemptions associated with implementation of SVM education components, but additional research is required to follow-up and confirm, especially as regards online education modules. [ABSTRACT FROM AUTHOR]

• The COVID-19 pandemic has challenged traditional vaccine guidance infrastructure. • NACI made many strategic adaptations to facilitate timely vaccine advice in Canada. • The pandemic highlighted critical roles for NITAGs in vaccine program design. • Learning from COVID-19 pandemic adaptations, we see a roadmap for future pandemics. The COVID-19 pandemic has challenged traditional vaccine guidance infrastructure and frameworks, and added urgency and complexity to the operation of National Immunization Technical Advisory Groups (NITAGs). Canada's National Advisory Committee on Immunization (NACI) provides immunization guidance to the Public Health Agency of Canada (PHAC) who publicly shares expert and evidence-informed guidance with Canadian provinces and territories. Throughout the pandemic, NACI and PHAC implemented many adaptations to meet urgent needs for pandemic vaccine guidance. In this paper, we describe: structural adaptations in response to the accelerated pace and amount of work required to issue recommendations that were timed around product authorizations and dynamic epidemiology; technical adaptations in response to rapidly evolving evidence of variable quality which required close monitoring, and which promoted reliance on basic vaccine principles due to incomplete direct evidence; the need to provide nimble advice (e.g., off-label recommendations, preferential recommendations); communications adaptations (e.g. identify sustainable spokespeople for the committee, receive stakeholder feedback, and ensure urgent nuanced advice was communicated to a diverse audience); and research adaptations focussing on solutions to constrained supply (e.g. prioritisation, extended intervals, and heterologous schedules). The early pandemic vaccine experience has created a roadmap of lessons and adaptations that should be leveraged in future pandemic vaccine programs, and has highlighted the essential role of NITAGs to complement regulatory structures during pandemics to ensure timely, impactful, and evidence-informed public health vaccine guidance. [ABSTRACT FROM AUTHOR]

Background: Social networks have an important impact on our health behaviours, including vaccination. People's vaccination beliefs tend to mirror those of their social network. As social networks are homogenous in many ways, we sought to determine in the context of COVID-19 which factors were most predictive of belonging to a mostly vaccinated or unvaccinated social group., Methods: We conducted a cross-sectional survey among Canadian residents in November and December 2021. Participants were asked about the vaccination status of their social networks their beliefs relating to COVID-19, and various sociodemographic factors. Respondents were split into three groups based on social network vaccination: low-, medium-, and high-risk. Chi-squared tests tested associations between factors and risk groups, and an ordinal logistic model was created to determine their direction and strength., Results: Most respondents (81.1 %) were classified as low risk (i.e., a mostly vaccinated social network) and few respondents (3.7 %) were classified as high-risk (i.e., an unvaccinated social group). Both the chi-square test (29.2 % difference between the low- and high- risk groups [1.8 % vs. 31.0 %], p < 0.001) and the ordinal logistic model (odds ratio between the low- and high-risk groups: 14.45, p < 0.01) found that respondents' perceptions of COVID-19 as a "not at all serious" risk to Canadians was the most powerful predictor of belonging to a predominantly unvaccinated social circle. The model also found that those in mostly unvaccinated social circles also more often reported severe COVID-19 symptoms (odds ratio between the low- and high-risk groups: 2.26, p < 0.05)., Conclusion: Perception of COVID-19 as a threat to others may signal communities with lower vaccination coverage and higher risk of severe outcomes. This may have implications for strategies to improve public outreach, messaging, and planning for downstream consequences of low intervention uptake., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Since the approval of SARS-CoV-2 vaccines for younger children (those under the age of 12), uptake has been low. Despite widespread vaccination among older children and adults, these trends may undermine public health efforts to manage future waves of SARS-CoV-2 or spill over into other childhood vaccines. The objectives of this study were to understand parents' intentions to vaccinate their children (under age 12) against SARS-CoV-2, and to explore reasons for and against SARS-CoV-2 vaccination., Methods: A representative sample of parents of school-aged children (ages 3-11 years) from Canada's four largest provinces were invited in June 2021 to complete a survey on the impact of COVID-19 on schooling. The survey included specific questions on parents' intentions to vaccinate their child(ren) against SARS-CoV-2. Multinomial regression models were run to estimate associations between demographic factors, political affiliation and voting, concerns about individual / family health and vaccination intention., Results: A total of 74.0 % of parents (n = 288) intended to vaccinate their children with the SARS-CoV-2 vaccine, 18.3 % (n = 71) did not intend to vaccinate and 7.7 % (n = 30) were unsure. The strongest predictor of parental hesitancy was whether a parent had themselves been vaccinated. Other factors including past voting behaviour, dissatisfaction with the government's response to the pandemic, and relatively less concern about contracting SARS-CoV-2 were also correlated with hesitancy. Parents of older children were more likely to indicate plans to vaccinate their child(ren). Analysis of the reasons for hesitancy showed parents are concerned about the safety and side effects of the vaccine, as well as with processes of testing and approval., Interpretation: A considerable proportion of Canadian parents of younger school-aged children (ages 3-11) were unsure and/or hesitant about vaccinating their children against SARS-CoV-2. As well, a much larger proportion who are not necessarily hesitant have also not had their children vaccinated. Given the evolving nature of SARS-CoV-2, including the continued emergence of new variants, reaching younger children will be important for population health. Health providers should continue to work with government institutions to ensure clear communication regarding the safety, efficacy, and importance of child vaccines for reaching public health goals., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

The aim of this study was to explore the sociodemographic and individual-level factors associated with vaccine hesitancy in general, including political affiliation and beliefs in vaccine conspiracy theories, in a diverse group of Canadian adults within the context of the COVID-19 pandemic. 641 responses were included in the analysis, with those self-identifying as Indigenous, Black Canadian, and low-income (household income <$40,000) being sampled to yield data from historically marginalized populations. Demographic variables and responses to questions on vaccine hesitancy, and beliefs in vaccine conspiracy theories were used to explore explanatory variables of vaccine hesitancy. General linear regression models were fit using the method of least squares via PROC GLM and used to examine sociodemographic and individual explanatory variables of vaccine hesitancy. Age, ethnicity, political affiliation, and beliefs in vaccine conspiracies were associated with vaccine hesitancy. Findings are discussed in relation to the critical role of distrust and misinformation in hesitancy. Our data provide insight into how Canadian provincial governments may promote uptake of vaccines in ways that target diverse groups that may differ from those developed in a pre-pandemic context., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Currently, SARS-CoV-2 have been detected in farmed mink in 13 different countries. Due to the high susceptibility and transmissibility among mink, great concerns of mink serving as a reservoir to generate novel variants with unknown virulence and antigenic properties arose. These concerns have consequently resulted in entire mink productions being culled and banned. This study investigates the post-vaccination antibody response in the Canadian farmed mink vaccinated with a commercial Index spike protein-based vaccine, approved for use in cats, and compares the antibody response to that observed post infection in Danish farmed mink. Blood samples were obtained from 50 mink at the Canadian Centre for Fur Animal Research (CCFAR), Dalhousie University (Truro, Canada). The sera were initially analyzed for antibodies by enzyme-linked immunosorbent assay (ELISA), and selected sera was subsequently tested in a virus neutralization tests. The levels of neutralizing antibodies were evaluated for an ancestral D614G strain and a recent circulating SARS-CoV-2 variant of concern (Omicron BA.4). The results revealed that the vaccine induced a strong antibody response in mink by reaching antibody titer levels of up to 1:12800 in the ELISA. Moreover, high levels of neutralizing antibodies were obtained, and despite the great level of genetic differences between the ancestral and Omicron BA.4 strains, the vaccinated mink showed high levels of cross-reacting neutralizing antibodies. Interestingly, the antibody levels towards SARS-CoV-2 in the Canadian vaccinated mink were significantly higher than observed in recently SARS-CoV-2 infected Danish mink and equal to anamnestic responses following re-infection. In conclusion, the vaccine used in the Canadian farmed mink was able to induce a strong and broad-reacting antibody response in mink, which could limit the spread of SARS-CoV-2 in farmed mink and thereby reduce the risk of mink serving as a SARS-CoV-2 reservoir for human infections., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Objective: To describe self-reported reactogenicity, pregnancy outcomes, and SARS-CoV-2 infection following COVID-19 vaccination during pregnancy., Design: National, prospective cohort study., Setting: Participants across Canada were enrolled from July 2021 until June 2022., Population: Individuals pregnant during the COVID-19 pandemic, regardless of vaccination status, were included., Methods: The Canadian COVID-19 Vaccine Registry for Pregnant and Lactating Individuals (COVERED) was advertised through traditional and social media. Surveys were administered at baseline, following each vaccine dose if vaccinated, pregnancy conclusion, and every two months for 14 months. Changes to pregnancy or vaccination status, SARS-CoV-2 infections, or significant health events were recorded., Main Outcome Measures: Reactogenicity (local and systemic adverse events, and serious adverse events) within 1 week post-vaccination, pregnancy and neonatal outcomes, and subsequent SARS-CoV-2 infection., Results: Among 2868 participants who received 1-2 doses of a COVID-19 vaccine during pregnancy, adverse events described included: headache (19.5-33.9%), nausea (4.8-13.8%), fever (2.7-10.2%), and myalgia (33.4-42.2%). Reactogenicity was highest after the 2nd dose of vaccine in pregnancy. Compared to 1660 unvaccinated participants, there were no statistically significant differences in adverse pregnancy or infant outcomes, aside from an increased risk of NICU admission ≥ 24 h among the unvaccinated group. During follow-up, there was a higher rate of participant-reported SARS-CoV-2 infection in the unvaccinated compared to the vaccinated group (18[47.4%] vs. 786[27.3%])., Conclusions: Participant-reported reactogenicity was similar to reports from non-pregnant adults. There was no increase in adverse pregnancy and birth outcomes among vaccinated vs. unvaccinated participants and lower rates of SARS-CoV-2 infection were reported in vaccinated participants., Tweetable Abstract: No significant increase in adverse pregnancy or infant outcomes among vaccinated versus unvaccinated pregnant women in Canada., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Measles outbreaks have raised concerns of fatal infections in immunocompromised patients. Canadian guidelines advise administration of live vaccines, such as measles, mumps, and rubella (MMR), two yearsafter hematopoietic stem cell transplant (HSCT) yet studies have not assessed eligibility based on medication contraindications. We retrospectively reviewed the charts of 72 autologous (auto-HSCT) and 68 allogeneic (allo-HSCT) recipients at the Windsor Regional Cancer Center to determine MMR reactivity and eligibility based on administration of contraindicated medications two years post-HSCT. Reactivity to measles, mumps, and rubella in auto-HSCT recipients was 49.1 %, 28.8 %, and 52.3 %, respectively, and in allo-HSCT recipients was 75.6 %, 57.8 %, and 64.4 %, respectively. Immunity to all three components was significantly different between transplant types (p = 0.0002). Nearly 80 % of auto-HSCT patients were on a contraindicated medication at two years compared to 45 % of allo-HSCT recipients. Auto-HSCT recipients require MMR revaccination, but it is contraindicated in a large proportion of patients., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

In the province of Quebec, Canada, a 2 + 1 dose pneumococcal conjugate vaccine (PCV) program for children was implemented in 2004. PCV7 was replaced by PCV10 in 2009, by PCV13 in 2011 and by PCV10 in 2018, without catch-up in all instances. The objective was to estimate PCV13 effectiveness to prevent serotype 3 invasive pneumococcal disease in children aged less than 5 years, using 2010-2018 mandatory notification and laboratory surveillance data, an indirect cohort design and multivariate logistic regression models. A total of 29 cases of serotype 3 and 290 non-vaccine serotype cases as controls were analysed. Overall vaccine effectiveness (≥1 dose) was estimated at 59% [-39% to 88%]. During the first year after the last dose effectivness was 88% [47% to 97%] whereas no protection was observed thereafter. There was no trend towards increased effectiveness with the number of doses. PCV13 protection against serotype 3 IPD seems to be short-lived., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Potential conflicts of interest The sponsor had no role in the design and conduct of the study, collection, management, analysis, and interpretation of the data, and preparation, review, and approval of the manuscript. This research received no other external financial or non-financial support. All co-authors have nothing to disclose., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

In Canada, the first COVID-19 vaccine was approved for use in December 2020, marking the beginning of a large vaccination campaign. The campaign was not only unprecedented in terms of reach, but also with regards to the amount of information about vaccines that circulated in traditional and social media. This study's aim was to describe COVID-19 vaccine related discourses in Canada through an analysis of editorial cartoons. We collected 2172 cartoons about COVID-19 published between January 2020 and August 2022 in Canadian newspapers. These cartoons were downloaded and a first thematic analysis was conducted using the WHO-EPIWIN taxonomy (cause, illness, treatment, interventions, and information). From this, 389 cartoons related to COVID-19 vaccines were identified under the treatment category. These were subjected to a second thematic analysis to assess main themes (e.g., vaccine development, campaign progress, etc.), characters featured (e.g., politicians, public figures, public) and position with respect to vaccine (favorable, unfavorable, neutral). Six main themes emerged: Research and development of vaccines; Management of the vaccination campaign; Perceptions of and experiences with vaccination services; Measures and incentives to increase COVID-19 vaccine uptake; Criticism of the unvaccinated; and Effectiveness of vaccination. Our analysis revealed a shift in attitudes toward COVID-19 vaccination from high hopes to disenchantment, which may reflect some vaccine fatigue. In the future, public health authorities could face some challenges in maintaining confidence and high COVID-19 vaccine uptake., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Emerging infectious diseases like COVID-19 will remain a concern for the foreseeable future, and determinants of vaccination and other mitigation behaviors are therefore critical to understand. Using data from the first two waves of the Canadian COVID-19 Experiences Survey (CCES; N = 1,958; 66.56 % female), we examined social cognitive predictors of vaccination status, transition to acceptance and mitigation behaviors in a population-representative sample. Findings indicated that all social cognitive variables were strong predictors of mitigation behavior performance at each wave, particularly among unvaccinated individuals. Among those who were vaccine hesitant at baseline, most social cognitive variables predicted transition to fully vaccinated status at follow-up. After controlling for demographic factors and geographic region, greater odds of transitioning from unvaccinated at CCES Wave 1 to fully vaccinated at CCES Wave 2 was predicted most strongly by a perception that one's valued peers were taking up the vaccine (e.g., dynamic norms (OR = 2.13 (CI: 1.54,2.93)), perceived effectiveness of the vaccine (OR = 3.71 (CI: 2.43,5.66)), favorable attitudes toward the vaccine (OR = 2.80 (CI: 1.99,3.95)), greater perceived severity of COVID-19 (OR = 2.02 (CI: 1.42,2.86)), and stronger behavioral intention to become vaccinated (OR = 2.99 (CI: 2.16,4.14)). As a group, social cognitive variables improved prediction of COVID-19 mitigation behaviors (masking, distancing, hand hygiene) by a factor of 5 compared to demographic factors, and improved prediction of vaccination status by a factor of nearly 20. Social cognitive processes appear to be important leverage points for health communications to encourage COVID-19 vaccination and other mitigation behaviors, particularly among initially hesitant members of the general population., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The "risk compensation hypothesis" holds that vaccinated individuals may be less motivated to protect themselves using other COVID-19 mitigation behaviors-e.g., masking, distancing and hand hygiene-given that they may perceive their infection risk to be lower. The current investigation provides an empirical test of the risk compensation hypothesis in the COVID-19 context using prospective data from the Canadian COVID-19 Experiences Survey (CCES). The survey comprised 1,958 unvaccinated and fully vaccinated individuals drawn from a representative sample, using quota sampling to ensure substantial representation of unvaccinated individuals. Two waves of data were collected 6 months apart. Findings revealed that vaccinated individuals performed COVID-19 mitigation behaviors significantly more frequently than their unvaccinated counterparts, and they also showed lower rates of attenuation as the pandemic continued. In summary, our findings do not support the risk compensation hypothesis; instead they support the notion that people adopt vaccination and other protective behaviors in parallel., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Health care providers' recommendations can play an important role in individuals' vaccination decisions. Despite being one of the most popular complementary and alternative medicine (CAM), naturopathy is understudied in relation to vaccination decisions. We sought to address this gap through this study of vaccination perspectives of naturopathy practitioners in the province of Quebec, Canada. We conducted in-depth interviews with 30 naturopaths. Thematic analysis was conducted. Main themes were developed deductively (i.e., based on prior literature) and expanded through inductive coding of the data. Participants noted that they discuss vaccination in their practice, but only when clients asked questions or wanted advice. Naturopaths described refraining from explicitly recommending for or against vaccination. Instead, they focus on empowering their clients to make their own informed decision regarding vaccination. Most participants noted that they direct clients towards sources of information so that clients could decide for themselves, but some mentioned they discussed with clients what they considered to be risks associated with vaccination, as well as its benefits. These discussions were framed through a personalized and individual approach with clients., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Although mumps vaccination has been routine in Canada for decades, mumps cases and outbreaks continue to occur periodically. Mumps surveillance, including monitoring of the mumps virus genotype associated with disease activity, is important to document baseline activity and to advance further research into vaccine effectiveness. Here we describe a detailed analysis of mumps cases that have been detected in Canada from 2002 to 2020, with a focus on the mumps molecular epidemiology. In total, 7395 cases of mumps were reported to the surveillance system, with outbreaks occurring in the years 2007, 2010 and 2016 to 2018. Adolescents and young adults aged 15 to 29 years had the highest risk of being a case (rate ratios ranging from 1.50 to 2.29), compared to adults aged 30 to 39. Genotypes of mumps viruses were determined in 3225 specimens. Genotype G was predominantly detected (96% of genotyped specimens) and was first reported in 2005. Other genotypes were more likely to be detected in cases that also reported travel (or were linked to imported cases) than the cases with genotype G detected (p < 0.0001). The genotype G viruses had little sequence diversity in the 316 nucleotide window used for genotyping (the small hydrophobic protein gene) and mainly belonged to a single phylogenetic lineage that included the MuVi/Sheffield.GBR/1.05 reference sequence. The analysis of over ten years of data has demonstrated that mumps genotype G, specifically belonging to a single lineage, the Sheffield lineage, is the endemically circulating virus in Canada. This lineage is seen also in other countries using the genotype A vaccine. Mumps remains endemic despite high MMR vaccination coverage which has been sufficient to eliminate circulation of measles and rubella in Canada, raising the hypothesis of the evolution towards a vaccine escape mumps virus., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Crown Copyright © 2023. Published by Elsevier Ltd. All rights reserved.)

Introduction: Intersectionality refers to the interconnectedness of various social locations creating unique experiences for individuals and groups, in the context of systems of privilege and oppression. As part of immunization coverage research, intersectionality allows healthcare professionals and policymakers to become aware of the constellation of characteristics contributing to low vaccine uptake. The objective of this study was to examine the application of intersectionality theory or concepts, and the appropriate use of sex and gender terminology, in Canadian immunization coverage research., Materials and Methods: The eligibility criteria for this scoping review included English or French language studies on immunization coverage among Canadians of all ages. Six research databases were searched without date restrictions. We searched provincial and federal websites, as well as the Proquest Dissertations and Theses Global database for grey literature., Results: Of 4725 studies identified in the search, 78 were included in the review. Of these, 20 studies included intersectionality concepts, specifically intersections of individual-level characteristics influencing vaccine uptake. However, no studies explicitly used an intersectionality framework to guide their research. Of the 19 studies that mentioned "gender", 18 had misused this term, conflating it with "sex"., Conclusions: Based on our findings, there is an evident lack of intersectionality framework utilization in immunization coverage research in Canada, as well as misuse of the terms "gender" and "sex". Rather than only focusing on discrete characteristics, research should explore the interaction between numerous characteristics to better understand the barriers to immunization uptake in Canada., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Introduction: In 2021, the ten provinces in Canada enacted COVID-19 vaccine mandates that restricted access to non-essential businesses and services to those that could provide proof of full vaccination to decrease the risk of transmission and provide an incentive for vaccination. This analysis aims to examine the effects of vaccine mandate announcements on vaccine uptake over time by age group and province., Methods: Aggregated data from the Canadian COVID-19 Vaccination Coverage Surveillance System (CCVCSS) were used to measure vaccine uptake (defined as the weekly proportion of individuals who received at least one dose) among those 12 years and older following the announcement of vaccination requirements. We performed an interrupted time series analysis using a quasi-binomial autoregressive model adjusted for the weekly number of new COVID-19 cases, hospitalizations, and deaths to model the effect of mandate announcements on vaccine uptake. Additionally, counterfactuals were produced for each province and age group to estimate vaccine uptake without mandate implementation., Results: The times series models demonstrated significant increases in vaccine uptake following mandate announcement in BC, AB, SK, MB, NS, and NL. No trends in the effect of mandate announcements were observed by age group. In AB and SK, counterfactual analysis showed that announcement were followed by 8 % and 7 % (310,890 and 71,711 people, respectively) increases in vaccination coverage over the following 10 weeks. In MB, NS, and NL, there was at least a 5 % (63,936, 44,054, and 29,814 people, respectively) increase in coverage. Lastly, BC announcements were followed by a 4 % (203,300 people) increase in coverage., Conclusion: Vaccine mandate announcements could have increased vaccine uptake. However, it is difficult to interpret this effect within the larger epidemiological context. Effectiveness of the mandates can be affected by pre-existing levels of uptake, hesitancy, timing of announcements and local COVID-19 activity., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Crown Copyright © 2023. Published by Elsevier Ltd. All rights reserved.)

Objectives: To assess the guideline concordance of medical school requirements for students' proof-of-immunity in the United States (US) and Canada., Methods: National guidelines for healthcare worker proof-of-immunity to measles, mumps, rubella, and varicella were compared to admission requirements for 62 US and 17 Canadian medical schools., Results: All surveyed schools accepted at least one recommended form of proof-of-immunity, however, contrary to national guidelines, 16% of surveyed US schools asked for a serologic titer, and only 73-79% US schools accepted vaccination as the sole proof-of-immunity., Conclusions: The requirement of numerical, non-standardized serologic testing highlights an oversight in medical school admissions documentation. The requirement for quantitative values to demonstrate immunity is not practical from a laboratory standpoint, and is not needed to show individual immunity to these vaccine-preventable diseases. Until a more standardized process is adopted, laboratories will need to provide clear documentation and direction for quantitative titer requests., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: A decline in routine vaccination was reported by some countries early in the COVID-19 pandemic. In the context of the pandemic, determinants of routine childhood vaccination may have changed. Changes over time in parents' perceptions of routine vaccines and intentions for their children during the pandemic have not been fully explored. Understanding changes provides opportunities to promote routine childhood vaccines and address factors that may compromise parents' acceptance., Methods: We conducted longitudinal analysis of two sequential national surveys during the pandemic (Dec 2020 and Oct/Nov 2021) to assess changes over time in Canadian parents' perceptions of routine childhood vaccines, intentions to vaccinate, access for their children ≤ 17 years, and differences among sociodemographic characteristics. McNemar-Bowker tests were used to determine changes in parents' responses collected at two time points., Results: Of the 650 parents in the sample, 25.1% with a child ≤ 6 years and 20.5% with a child 7-17 years perceived that routine childhood vaccines were more important because of the pandemic. Between the two time points, parents' confidence in the safety (72.8% to 80.2%, p <.001) and effectiveness (81.7% to 85.2%, p =.007) of routine vaccines increased, parents were more engaged in vaccine decision-making (73.4% to 79.8%, p =.006), and everyday stress preventing vaccination decreased (78.8% to 68.5%, p <.001). Acceptance of routine vaccines increased (82.9% to 86.5%, p =.021), but more parents were undecided about influenza vaccination (12.6% to 20.3%, p =.002). Compared to parents with 1 child, those with 2 children reported increased vaccination acceptance (82.6% to 87.4%, p =.024)., Interpretation: Under the spotlight of COVID-19, parents' confidence in routine vaccines, engagement in decision-making, and vaccination acceptance increased. Vaccination providers should support parents' decision-making as they navigate routine childhood vaccine uncertainties. Differences in parents' acceptance of routine and influenza vaccines for their children highlight the need for targeted communication strategies for specific vaccines., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

At the beginning of 2021, when Canada started distribution of COVID-19 vaccines, the unprecedented scope and severity of the pandemic led to very high levels of public awareness and attention, with Canadians actively seeking information. We argue that while there was continuous public health communication about COVID-19 and the newly available vaccines, these messages did not address the specific anxieties elicited by the novel vaccines, even as vaccination guidelines changed. Instead, public health messages about COVID-19 vaccines resembled those aimed at reducing vaccine hesitancy for routine immunization and did not sufficiently address the constant changes to COVID-19 vaccine recommendations. In a context of heightened public concern and significant public attention, it is crucial for communicators to acknowledge that hesitancy is vaccine-specific, and that novel diseases and new vaccines produce specific concerns. Long-term strategies should address the novelty of the technology and of the risk, thoroughly explain the reasons for shifting vaccination guidelines, and leverage trusted sources, such as community leaders. Further, as COVID-19 vaccines become less effective against some of the more recent variants of the virus, vaccine messaging needs to be tailored to evolve with shifting realities to not lose productive gains in the COVID-19 vaccination campaign to date., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Vaccination is an essential public health intervention to control the COVID-19 pandemic. A minority of Canadians, however, remain hesitant about COVID-19 vaccines, while others outright refuse them. We conducted focus groups to gauge perceptions and attitudes towards COVID-19 vaccines in people who live in a region with historically low rates of childhood vaccination. Participants discussed their perception of COVID-19 vaccines and their intention to get vaccinated, and the low rate of COVID-19 vaccine uptake in Manitoba's Southern Health Region compared to other regions in Canada. We identified three drivers of vaccine hesitancy: (1) risk perceptions about COVID-19 and the vaccines developed to protect against it, (2) religious and conservative views; and (3) distrust in government and science. Participant proposed recommendations for improving communication and uptake of the COVID-19 vaccines included: public health messages emphasising the benefits of vaccination; addressing the community's specific concerns and dispelling misinformation; highlighting vaccine safety; and emphasising vaccination as a desirable behaviour from a religious perspective. Understanding the specific anxieties elicited by COVID-19 vaccines in areas with low childhood immunization rates can inform risk communication strategies tailored to increase vaccination in these specific regions. This study adds important information on potential reasons for vaccine hesitancy in areas with historically low rates of childhood vaccination, and provides important lessons learned for future emergencies in terms of vaccine hesitancy drivers and effective risk communication to increase vaccine uptake., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Uptake of vaccination during pregnancy in Canada is lower than comparator countries. A recommendation from a trusted perinatal healthcare provider is a key opportunity to promote vaccine uptake and improve confidence. This study aims to identify barriers and opportunities to vaccination in midwifery care. Seventeen semi-structured telephone interviews with practicing midwives, educators and public health professionals with immunization training experiences were conducted. Documents pertaining to the midwifery profession (approx. 50) were reviewed. Inductive thematic analysis identified logistical, interprofessional, and information barriers preventing Canadian midwives from administering vaccines and counseling clients about vaccination, as well as opportunities to address each barrier. Key interventions at the level of logistics, training, and client information materials would help address barriers to the integration of midwives into the provision and recommendation of vaccines in perinatal care across Canada., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Canadian and international data suggest the risk of myocarditis and/or pericarditis is elevated during the week after mRNA COVID-19 vaccination, particularly in younger age groups, in males, and after second doses., Objectives: This article examines whether there is a product-specific difference in the risk for myocarditis and/or pericarditis between the two mRNA vaccines administered in Canada: BNT162b2 (Pfizer-BioNTech Comirnaty) and mRNA-1273 (Moderna Spikevax)., Materials and Methods: Reporting rates of myocarditis and/or pericarditis were calculated from reports received by the Canadian Adverse Events Following Immunization Surveillance System from December 2020-March 2022. Excess cases and attributable incidence among individuals aged 18-39 were estimated for each vaccine in comparison with background rates from 2015 to 2019. Head-to-head comparisons used Poisson regression, conditioned on week of vaccine administration, to estimate rate ratios for the week after mRNA-1273 vaccination versus the week after BNT162b2, by age and sex as well as overall. Analyses were restricted to May 30-March 13, 2021, when heightened media awareness was unlikely to have affected reporting rates for the two products differentially., Results: In 18-29 year-old males who received a second dose of mRNA COVID-19 vaccine, attributable risk of myocarditis and/or pericarditis was found to be 5.69 (95% CI: 4.07 - 7.95; p < 0.001) times higher among mRNA-1273 recipients (n = 106) as compared to BNT162b2 recipients (n = 33). In the same group, Poisson regression modelling estimated that the risk of myocarditis and/or pericarditis was 4.72 (p-value = <0.001) times higher after mRNA-1723 compared to BNT162b2 vaccination., Conclusions: The risk of myocarditis and/or pericarditis is higher after mRNA-1723 vaccination than BNT162b2 vaccination in those aged 18-39 years, especially in males aged 18-29 years, where the risk is several times higher., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Crown Copyright © 2022. Published by Elsevier Ltd. All rights reserved.)

Since 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection resulting in the coronavirus disease 2019 (COVID-19) has afflicted hundreds of millions of people in a worldwide pandemic. Several safe and effective COVID-19 vaccines are now available. However, the rapid emergence of variants and risk of viral escape from vaccine-induced immunity emphasize the need to develop broadly protective vaccines. A recombinant plant-derived virus-like particle vaccine for the ancestral COVID-19 (CoVLP) recently authorized by Canadian Health Authorities and a modified CoVLP.B1351 targeting the B.1.351 variant (both formulated with the adjuvant AS03) were assessed in homologous and heterologous prime-boost regimen in mice. Both strategies induced strong and broadly cross-reactive neutralizing antibody (NAb) responses against several Variants of Concern (VOCs), including B.1.351/Beta, B.1.1.7/Alpha, P.1/Gamma, B.1.617.2/Delta and B.1.1.529/Omicron strains. The neutralizing antibody (NAb) response was robust with both primary vaccination strategies and tended to be higher for almost all VOCs following the heterologous prime-boost regimen., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. CD, SPR, GA, MAD, BJW and ST are either employees of Medicago Inc or receive salary support from Medicago Inc. CG is an employee of the GSK group of companies and reports ownership of GSK shares., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Background: Starting in 2015/16, most Canadian provinces introduced publicly-funded human papillomavirus (HPV) vaccination programs for gay, bisexual, and other men who have sex with men (GBM) aged ≤ 26 years. We estimated 12-month changes in HPV vaccine coverage among community-recruited GBM from 2017 to 2021 and identified baseline factors associated with vaccine initiation (≥1 dose) or series completion (3 doses) among participants who were unvaccinated or partially vaccinated at baseline., Methods: We recruited sexually-active GBM aged ≥ 16 years in Montreal, Toronto, and Vancouver, Canada, from 02/2017 to 08/2019 and followed them over a median of 12 months (interquartile range = 12-13 months). We calculated the proportion who initiated vaccination (≥1 dose) or completed the series (3 doses) by 12-month follow-up. Analyses were stratified by city and age-eligibility for the publicly-funded programs at baseline (≤26 years or > 26 years). We used multivariable logistic regression to identify baseline factors associated with self-reported incident vaccine initiation or series completion., Results: Among 165 unvaccinated participants aged ≤ 26 years at baseline, incident vaccine initiation (≥1 dose) during follow-up was 24.1% in Montreal, 33.3% in Toronto, and 38.9% in Vancouver. Among 1,059 unvaccinated participants aged > 26 years, incident vaccine initiation was 3.4%, 8.9%, and 10.9%, respectively. Higher education and trying to access pre-exposure prophylaxis for HIV were associated with incident vaccination among those aged ≤ 26 years, while younger age, residing in Vancouver (vs. Montreal), being diagnosed with anogenital warts, having both government and private extended medical insurance, and being vaccinated against influenza were associated with incident vaccination among those aged > 26 years., Conclusions: We observed substantial gains in HPV vaccine coverage among young GBM within 5 + years of targeted program implementation, but gaps remain, particularly among older men who are ineligible for publicly-funded programs. Findings suggest the need for expanded public funding or insurance coverage for HPV vaccines., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper: [Joseph Cox reports a relationship with ViiV Healthcare, Gilead Sciences and Merck Canada that includes: consulting or advisory and funding grants. Francois Coutlee reports a relationship with Roche Diagnostics, Becton Dickinson, and Merck Sharp and Dome that includes: consulting or advisory, funding grants, and speaking and lecture fees. Darrell H.S. Tan reports a relationship with Abbvie, Gilead, Viiv Healthcare, and Glaxo Smith Kline that includes: funding grants. Shelley L. Deeks is the current Chair of the National Advisory Committee on Immunization; Chantal Sauvageau is a member of the Québec Immunization Committee.]., (Copyright © 2022. Published by Elsevier Ltd.)

We aimed to determine population immunity to measles in Canada, and to assess the risk of future outbreaks. We tested 11,176 sera from Cycles 2 (2009-2011) and 3 (2011-2013) cohorts from the biobank of Statistics Canada's Canadian Health Measures Survey (CHMS) using the BioPlex 2220 MMRV IgG assay. We then tested all BioPlex negative and equivocal samples using a more sensitive Plaque Reduction Neutralization Test (PRNT). We determined the weighted proportion of positive, equivocal, and negative samples by age, sex, region and whether individuals were born in Canada. We found that 90.0% (95% confidence interval (CI): 88.2, 91.9) of samples were positive, 4.5% (95% CI: 3.4, 5.5) were equivocal and 5.5% (95% CI: 4.3, 6.7) were negative. Individuals in the 12-19 year age band had the lowest proportion positive at 78.7% (95% CI: 74.2, 83.2) and the highest proportion of positive samples was found in those 60-79 years (99.6%, 95% CI: 99.3, 99.9). Seropositivity was consistently <90% across a broad range of pediatric and adult age bands (6-39 years). We found that a slightly higher proportion of females were positive (91.9%, 95% CI: 90.1, 93.6) compared to males (88.3%, 95% CI: 85.8, 90.7). When taking into account interaction between age and born in Canada status, we found individuals born in Canada aged 19 and under were less susceptible (OR = 0.6 (95% CI: 0.4, 0.95)) compared to those born outside Canada whereas, those aged 20 and over were more susceptible (OR = 1.7 (95% CI: 1.1, 2.8)). Our findings indicate that measles immunity in Canada is below the 95% immunity threshold required to sustain measles elimination, underscoring the importance of maintaining high vaccine coverage to prevent future measles outbreaks and sustain Canada's elimination status., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier Ltd.)

To effectively end the pandemic, the acceptance of effective vaccines against COVID-19 is critical. Comments posted in online platforms act as a barometer for understanding public concerns regarding vaccination and can be used to inform communication strategies for the 'moveable middle'. The aim of this exploratory study was to identify online dialogue regarding the nature of vaccine hesitancy related to COVID-19 vaccine(s). We analyzed user comment threads in response to news reports regarding COVID-19 vaccines on the Canadian Broadcasting Corporation national news website (with as many as 9.4 million unique visitors per day). User comments (n = 1145) were extracted from 19 articles between March 2020 and June 15th, 2020. Comments were then coded inductively for content to establish a coding framework that was subsequently applied to the dataset. Our data provide empirical support for misrepresentation as a form of misinformation and further demonstrate the utility of social media content as data for social research that informs public health communication materials. The data point to the need for, and value of, rapid communication interventions to foster vaccine acceptance. False information will continue to create challenges for delivering COVID-19 vaccines. Communication strategies to get ahead of the pace of misinformation are critical, particularly in light of boosters and the possibility of COVID-19 vaccination on an annual basis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

We used an indirect cohort analysis in children under 5 years-old from 2002 to 2018 to examine vaccine effectiveness (VE) of the 7-valent pneumococcal conjugate vaccine (PCV) (3 + 1 doses in most regions) and the 13-valent PCV (2 + 1 doses in all regions) against invasive pneumococcal disease (IPD) caused by vaccine serotypes in children in Canada. Cases were identified from the Canadian Immunization Monitoring Program ACTive (IMPACT), a national active surveillance network of 12 tertiary care pediatric hospitals that represent about 90% of tertiary care hospital beds in Canada. There were 1477 children evaluated for PCV7 VE and 489 for PCV13 VE. PCV7 VE in children with vaccination up to date for their age was 96% (95% CI: 67-99%) after a single dose and 95% (95% CI: 92-97%) after ≥2 doses. The VE was 91% (95% CI: 85-94%) in children who had received doses but were not up to date for their age. PCV13 VE in children with vaccinations up to date for their age was 55% (95% CI: 28-72%) after ≥2 doses. The PCV13-vaccine serotypes causing breakthrough IPD in children up to date for their age with 2+ doses of PCV13 were 3 (13/27, 48.2%),19A (11/27, 40.7%), and 19F (3/27, 11.1%). When serotype 3 and 19A were excluded, the VE of PCV13 against the remaining vaccine serotypes was 89% (95% CI: 64-97%) in children with ≥2 doses. The lower VE of PCV13 may be due to lower effectiveness against serotypes 3 and 19A, which could be influenced by the change in dosing schedule from 4 to 3 total doses with the introduction of PCV13, combined with vaccine uptake of 80%. However, PCV13 still provides the benefit of protection against more serotypes than PCV7, and good VE against all serotypes except 3 and 19A., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective(s): In the context of age- and risk-based pneumococcal vaccine recommendations in Canada, this study presents updated data from active surveillance of pneumococcal community acquired pneumonia (pCAP) and invasive pneumococcal disease (IPD) in hospitalized adults from 2010 to 2017., Methods: S. pneumoniae was detected using culture (blood and sputum), and urine antigen detection (UAD). Serotyping was performed with Quellung, PCR, or using the PCV13- and PPV23 (non-PCV13)-specific UADs. Laboratory results, demographic, and outcome data were categorized by age (16-49, 50-64, and 65 + ) and by disease [non-bacteremic pCAP, bacteremic pCAP, and IPD(non-CAP)]., Results: 11,129 CAP cases and 216 cases of IPD (non-CAP) were identified. Laboratory testing for S. pneumoniae was performed in 8912 CAP cases, identifying 1264 (14.2%) as pCAP. Of pCAP cases, 811 (64.1%) were non-bacteremic and 455 (35.9%) were bacteremic. Adults 65 + years represented 54.5% of non-bacteremic pCAP, 41.4% of bacteremic pCAP, and 48.6% of IPD cases. Adults 50-64 years contributed 30.3%, 33.1%, and 29.9%, respectively. In pCAP, PCV13 serotypes declined between 2010 and 2014 due to declines in serotypes 7F and 19A, then plateaued from 2015 to 2017 with persistence of serotype 3. In later study years, non-bacteremic pCAP was predominant, and PPV23 (non-PCV13) serotypes increased from 2015 to 2017, with serotypes 22F, 11A, and 9 N being most frequently identified. Compared to non-pCAP, pCAP cases were more likely to be admitted to intensive care units and require mechanical ventilation. These outcomes and mortality were more common in bacteremic pCAP and IPD, versus non-bacteremic pCAP., Conclusion(s): Along with IPD, pCAP surveillance (bacteremic and non-bacteremic) is important as their trends may differ over time. With insufficient herd protection from PCV13 childhood immunization, or use of PPV23 in adults, this study supports direct adult immunization with PCV13 or higher valency conjugate vaccines to reduce the residual burden of pCAP and IPD., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: High rates of COVID-19 vaccination uptake are required to attain community immunity. This study aims to identify factors associated with COVID-19 vaccine uncertainty and refusal among young adults, an underexplored population with regards to vaccine intention generally, in two high-income settings: Canada and France., Methods: A cross-sectional online survey was conducted from October to December 2020 among young adults ages 18-29 years (n = 6663) living in Canada (51.9%) and France (48.1%). Multinomial logistic regression analyses were performed to identify the sociodemographic and COVID-19-related measures (e.g., prevention behavior and perspectives, health-related concerns) associated with vaccine uncertainty and refusal. We conducted weighted analyses by age, gender and province/region of residence., Results: Intention to accept vaccination was reported by 84.3% and 59.7% of the sample in Canada and France, respectively. Higher levels of vaccine uncertainty and refusal were observed in France compared to Canada (30.1% versus 11%, 10.2% versus 4.7%). In both countries, we found higher levels of vaccine acceptance among young adults who reported COVID-19 prevention actions. Vaccine uncertainty and refusal were associated with living in a rural area, having lower levels of educational attainment, not looking for information about COVID-19, not wearing a face mask, and reporting a lower level of concern for COVID-19's impact on family. Participants who had been tested for COVID-19 were less likely to intend to refuse a vaccine., Conclusions: COVID-19 vaccine acceptance was high among young adults in Canada and France during a time in which vaccines were approved for use. Targeted interventions to build confidence in demographic groups with greater hesitance (e.g., rural and with less personal experience with COVID-19) may further boost acceptance and improve equity as vaccine efforts continue to unfold., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: Over the last 2 decades, Haemophilus influenzae type a (Hia) has emerged as a significant cause of invasive disease in some geographic regions and populations. Recognition of the importance of Hia in the etiology of serious disease, particularly in young children, prompted the development of a new protein-capsular polysaccharide conjugate vaccine, similar in design to a vaccine against H. influenzae type b. At present, understanding of Hia immunology is incomplete; the immunological correlate of protection against invasive disease is unknown., Methods: Our objective was to study Hia antibody in children of various ages residing in a Canadian province with low incidence rates of invasive disease. The enzyme-linked immunosorbent assays were performed to quantify plasma IgG and IgM specific to Hia capsular polysaccharide in 133 children (3 months to 16 years)., Results: Both anti-Hia IgG and IgM concentrations increased with age and were significantly higher in older children; a positive correlation between age and concentrations of Hia antibody was found. IgM antibody concentrations were significantly higher than IgG, with mean IgM concentrations over 10 times larger than IgG across all age groups., Conclusions: The steady rise of naturally acquired, Hia-specific IgG and IgM concentrations in a pediatric population with low incidence rates of invasive Hia disease suggests the exposure to some cross-reactive environmental antigens as a major source of the antibody. However, the carriage rates of Hia in the region are unknown and further seroepidemiological studies are warranted. Although natural antibody may protect certain population groups against invasive disease, immunization of younger children will be essential to prevent serious infections if Hia continues to spread across North America., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Introduction: Understanding how influenza vaccine uptake changed during the 2020/2021 influenza season compared to previous pre-pandemic seasons is a key priority, as is identifying the relationship between prior influenza vaccination and COVID-19 vaccine willingness., Methods: We analyzed data from a large, nationally representative cohort of Canadian residents aged 50 and older to assess influenza vaccination status three times between 2015 and 2020. We investigated: 1) changes in self-reported influenza vaccine uptake, 2) predictors of influenza vaccine uptake in 2020/2021, and 3) the association between influenza vaccination history and self-reported COVID-19 vaccine willingness using logistic regression models., Results: Among 23,385 participants analyzed for aims 1-2, influenza vaccination increased over time: 14,114 (60.4%) in 2015-2018, 15,692 (67.1%) in 2019/2020, and 19,186 (82.0%; combining those already vaccinated and those planning to get a vaccine) in 2020/2021. After controlling for socio-demographics, history of influenza vaccination was most strongly associated with influenza vaccination in 2020/2021 (adjusted odds ratio [aOR] 147.9 [95% CI: 120.9-180.9]); this association remained after accounting for multiple health and pandemic-related factors (aOR 140.3 [95% CI: 114.5-171.8]). To a lesser degree, those more concerned about COVID-19 were also more likely to report influenza vaccination in fall 2020, whereas those reporting a very negative impact of the pandemic were less likely to get vaccinated. Among 23,819 participants with information on COVID-19 vaccine willingness during the last quarter of 2020 (aim 3), prior influenza vaccination was most strongly associated with willingness to get a COVID-19 vaccine (aOR 15.1 [95% CI: 13.5-16.8] for those who had received influenza vaccine at all previous timepoints versus none)., Conclusions: Our analysis highlights the importance of previous vaccination in driving vaccination uptake and willingness. Efforts to increase vaccination coverage for influenza and COVID-19 should target individuals who do not routinely engage with immunization services regardless of demographic factors., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Although influenza vaccines provide protection against influenza viruses, concern has been raised that they may increase susceptibility to non-influenza respiratory viruses. As pandemic lockdowns end, temporal overlap of circulation of seasonal influenza viruses and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is expected. Understanding the impact of influenza vaccination on risk of coronavirus infection is therefore of considerable public health importance., Methods: We performed a secondary analysis of a randomized trial where children and adolescents in Canadian Hutterite colonies were randomly assigned by colony to receive the 2008-2009 seasonal inactivated trivalent influenza vaccine (TIV) or a control hepatitis A (HepA) vaccine. All 3273 colony members (vaccinated children and nonvaccine recipients) were followed for the primary outcome of RT-PCR confirmed seasonal coronavirus infection. Serum collected pre- and post-vaccination was analyzed for titers of IgG antibodies towards human coronaviruses (HCoV)., Results: The incidence of coronavirus infection was 0·18/1000 person-days in the colonies that received TIV vs 0.36/1000 person-days in the control group, hazard ratio (HR) 0.49 [0.21-1.17]. The risk reduction among non-vaccine recipients in the TIV group compared to the control group was HR 0.55 [0.24-1.23]. There was an increase in the geometric mean fold change of HCoV-OC43 antibody titers following TIV compared to HepA vaccine (mean difference 1.2 [0.38-2.06], p = 0.007), and an increase in geometric mean HCoV-NL63 antibody titers post-TIV (262.9 vs 342.9, p = 0.03)., Conclusion: The influenza vaccine does not increase the risk of a coronavirus infection. Instead, the influenza vaccine may reduce the rate of coronavirus infections by inducing cross-reactive anti-coronavirus IgG antibodies., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Previous studies have found higher rates of varicella susceptibility among migrants from tropical regions. This study seeks to estimate the prevalence of varicella susceptibility in a cohort of newly arrived refugees and refugee claimants at a primary care clinic in Toronto and to compare patients' self-reported history of varicella infection with serologic test results., Methods: We conducted a retrospective chart review of 1888 refugee patients aged 13 years and older rostered at a specialized primary care clinic in Toronto from December 2011 to October 2017. Basic sociodemographic variables, self-reported varicella history, and varicella serologic results were examined., Results: Based on serologic testing, 8.5% of individuals were varicella non-immune, with highest rates of varicella susceptibility among adolescents aged 13-19 years (13.5%). All adults over age 60 were varicella immune on serology (n = 56). A positive self-reported history of varicella infection was strongly predictive of varicella immunity on serology (PPV 96.8%; 95% CI: 95.2-97.9). A self-reported history of no prior varicella infection did not correlate reliably with serologic test results (NPV 15.8%; 95% CI: 13.3-18.0). A substantial proportion of patients (34.1%) were unsure of their varicella history., Conclusion: Identification and immunization of varicella susceptible refugee newcomers remains a health care priority. Self-reported history of varicella infection had mixed reliability as a predictor of varicella immunity., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Introduction: The National Advisory Committee on Immunization (NACI) makes recommendations for vaccines in Canada. To inform considerations for equity when making recommendations, the NACI Secretariat developed a matrix of factors that may influence vaccine equity. To inform the matrix we mapped the evidence for P 2 ROGRESS And Other factors potentially associated with unequal levels of illness or death from vaccine-preventable diseases (VPDs) and systematically reviewed the evidence for interventions aimed at reducing inequities., Methods: In October 2019 we searched Medline, Embase, and CINAHL. Two reviewers agreed on the included studies. Our primary outcomes were VPD-related hospitalizations and deaths. Secondary outcomes were differential vaccine access, and exposure, susceptibility, severity, and consequences of VPDs. Two reviewers appraised the certainty of evidence. We mapped the evidence for P 2 ROGRESS And Other factors and summarized the findings descriptively. We summarized the interventions narratively., Results: We identified 413 studies reporting on P 2 ROGRESS And Other factors. The most commonly investigated factors included age (n = 374, 89%), pre-existing conditions (n = 179, 42%), and gender identity or sex (n = 144, 34%). We identified 2 trials investigating the effects of interventions. One (n = 1249) provided very low certainty evidence that staff vaccination policies may reduce hospitalizations and deaths from influenza among private care home residents. The other (n not reported) provided very low certainty evidence that universal vaccination by nurses in clinics may reduce hospitalizations for rotavirus gastroenteritis compared with vaccination by physicians or no intervention., Conclusions: There is a large body of studies reporting on hospitalizations and deaths from VPDs stratified by P 2 ROGRESS And Other factors. We found only two trials examining the effects of interventions on hospitalization for or mortality from VPDs. This review has been helpful to NACI and will be helpful to similar organizations aiming to systematically identify and target health inequities through the development of vaccine program recommendations., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Declaration of Competing Interest Two study authors from the Centre for Immunization and Respiratory Infectious Diseases, Public Health Agency of Canada (SJI and MCT) contributed to the development of the protocol for the review, provided content expertise throughout the review process, and provided comments on draft versions of the report. The Public Health Agency of Canada was not directly involved in the design of the study, in the collection, analysis, and interpretation of data, nor in the writing of the report and decision to submit it for publication. The remaining authors (AG, SR, SS, JP, DKL, and LH) have no potential or actual conflicts of interest to declare. The findings and conclusions of this review are our own and do not necessarily represent the views of the National Advisory Committee on Immunization. No statement in this presentation should be construed as an official position of the National Advisory Committee on Immunization or the Public Health Agency of Canada., (Crown Copyright © 2021. Published by Elsevier Ltd. All rights reserved.)

Importance: The success in ending the COVID-19 pandemic rests partly on the mass uptake of the COVID-19 vaccine. Little work has been done to understand vaccine willingness among older adolescents and young adults. This is important since this age group may be less likely to adhere to public health guidelines., Objective: To understand willingness of getting a vaccine and reasons for vaccine hesitancy among a sample of older adolescents and young adults., Design: Data were from the Well-Being and Experiences study (The WE Study), a longitudinal community-based sample of older adolescents and young adults collected from Winnipeg, Manitoba, Canada from 2017 to 2020 (n = 664)., Setting: The study setting was a community-based observational longitudinal study., Participants: Participants for the study were aged 14 to 17 years old at baseline in 2016-17 (n = 1000). Data were also collected on one parent/caregiver. Waves 2 (n = 747) and 3 (n = 664) were collected in 2019 and 2020, respectively., Exposures: The main exposures were sociodemographic factors, health conditions, COVID-19 knowledge, and adversity history., Main Outcomes: The main outcomes were COVID-19 vaccine willingness, hesitancy, and reasons for hesitancy., Results: Willingness to get a COVID-19 vaccine was 65.4%. Willingness did not differ by age, sex, or mental health conditions, but did differ for other sociodemographic characteristics, physical health conditions, COVID-19 knowledge, practicing social/physical distancing, and adversity history. The most common reasons for not wanting a vaccine were related to safety, knowledge, and effectiveness. Sex differences were noted., Conclusions and Relevance: Increasing uptake of the COVID-19 vaccine among older adolescents and young adults may rely on targeting individuals from households with lower income, financial burden, and adversity history, and generating public health messaging specifically aimed at vaccine safety, how it works to protect against illness, and why it is important to protect oneself against a COVID-19 infection., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The Brighton Collaboration Viral Vector Vaccines Safety Working Group (V3SWG) was formed to evaluate the safety and characteristics of live, recombinant viral vector vaccines. The Modified Vaccinia Ankara (MVA) vector system is being explored as a platform for development of multiple vaccines. This paper reviews the molecular and biological features specifically of the MVA-BN vector system, followed by a template with details on the safety and characteristics of an MVA-BN based vaccine against Zaire ebolavirus and other filovirus strains. The MVA-BN-Filo vaccine is based on a live, highly attenuated poxviral vector incapable of replicating in human cells and encodes glycoproteins of Ebola virus Zaire, Sudan virus and Marburg virus and the nucleoprotein of the Thai Forest virus. This vaccine has been approved in the European Union in July 2020 as part of a heterologous Ebola vaccination regimen. The MVA-BN vector is attenuated following over 500 serial passages in eggs, showing restricted host tropism and incompetence to replicate in human cells. MVA has six major deletions and other mutations of genes outside these deletions, which all contribute to the replication deficiency in human and other mammalian cells. Attenuation of MVA-BN was demonstrated by safe administration in immunocompromised mice and non-human primates. In multiple clinical trials with the MVA-BN backbone, more than 7800 participants have been vaccinated, demonstrating a safety profile consistent with other licensed, modern vaccines. MVA-BN has been approved as smallpox vaccine in Europe and Canada in 2013, and as smallpox and monkeypox vaccine in the US in 2019. No signal for inflammatory cardiac disorders was identified throughout the MVA-BN development program. This is in sharp contrast to the older, replicating vaccinia smallpox vaccines, which have a known risk for myocarditis and/or pericarditis in up to 1 in 200 vaccinees. MVA-BN-Filo as part of a heterologous Ebola vaccination regimen (Ad26.ZEBOV/MVA-BN-Filo) has undergone clinical testing including Phase III in West Africa and is currently in use in large scale vaccination studies in Central African countries. This paper provides a comprehensive picture of the MVA-BN vector, which has reached regulatory approvals, both as MVA-BN backbone for smallpox/monkeypox, as well as for the MVA-BN-Filo construct as part of an Ebola vaccination regimen, and therefore aims to provide solutions to prevent disease from high-consequence human pathogens., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: The authors Ariane Volkmann, Heinz Weidenthaler, and Thomas Meyer are employees of Bavarian Nordic., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)