Methodological changes implemented over time to support accurate and timely COVID-19 vaccine coverage estimates: Ontario, Canada.

The COVID-19 vaccination program implementation in Ontario, Canada has spanned multiple years and is ongoing. To meet the challenges of the program, Ontario developed and implemented a new electronic COVID-19 immunization registry, COVaxON, which captures individual-level data on all doses administered in the province enabling comprehensive coverage assessment. However, the need for ongoing COVID-19 vaccine coverage assessments over a multi-year vaccination program posed challenges necessitating methodological changes. This paper describes Ontario's COVID-19 immunization registry, the methods implemented over time to allow for the ongoing assessment of vaccine coverage by age, and the impact of those methodological changes. Throughout the course of the vaccination program, four different methodological approaches were used to calculate age-specific coverage estimates using vaccination data (numerator) obtained from COVaxON. Age-specific numerators were initially calculated using age at time of first dose (method A), but were updated to the age at coverage assessment (method B). Database enhancements allowed for the exclusion of deceased individuals from the numerator (method C). Population data (denominator) was updated to 2022 projections from the 2021 national census following their availability (method D). The impact was most evident in older age groups where vaccine uptake was high. For example, coverage estimates for individuals aged 70-79 years of age for at least one dose decreased from 104.9 % (method B) to 95.0 % (method D). Thus, methodological changes improved estimates such that none exceeded 100 %. Ontario's COVID-19 immunization registry has been transformational for vaccine program surveillance. The implementation of a single registry for COVID-19 vaccines was essential for comprehensive near real-time coverage assessment, and enabled new uses of the data to support additional components of vaccine program surveillance. The province is well positioned to build on what has been achieved as a result of the COVID-19 pandemic and expand the registry to other routine vaccination programs.

Myocarditis or Pericarditis Events After BNT162b2 Vaccination in Individuals Aged 12 to 17 Years in Ontario, Canada.

Importance: The risk of myocarditis or pericarditis after COVID-19 messenger RNA vaccines varies by age and sex, and there is some evidence to suggest increasing risk with shorter intervals between dose 1 and 2 (ie, interdose interval). Objective: To estimate the incidence of reported myocarditis or pericarditis after BNT162b2 vaccine among adolescents and to describe the clinical information associated with these events. Design, Setting, and Participants: This was a population-based cohort study using passive vaccine safety surveillance data linked to the provincial COVID-19 vaccine registry. Included in the study were all adolescents aged 12 to 17 years in Ontario, Canada, who received 1 or more doses of BNT162b2 vaccine between December 14, 2020, and November 21, 2021, and reported an episode of myocarditis or pericarditis. Data were analyzed from December 15, 2021, to April 22, 2022. Exposure: Receipt of BNT162b2 (Comirnaty [Pfizer-BioNTech]) vaccine. Main Outcomes and Measure: Reported incidence of myocarditis or pericarditis meeting level 1 to 3 of the Brighton Collaboration case definition per 100 000 doses of BNT162b2 administered by age group (12-15 years vs 16-17 years), sex, dose number, and interdose interval. All clinical information associated with symptoms, health care usage, diagnostic test results, and treatment at the time of the acute event were summarized. Results: There were approximately 1.65 million doses of BNT162b2 administered and 77 reports of myocarditis or pericarditis among those aged 12 to 17 years, which met the inclusion criteria during the study period. Of the 77 adolescents (mean [SD] age, 15.0 [1.7] years; 63 male individuals [81.8%]), 51 (66.2%) developed myocarditis or pericarditis after dose 2 of BNT162b2. Overall, 74 individuals (96.1%) with an event were assessed in the emergency department, and 34 (44.2%) were hospitalized (median [IQR] length of stay, 1 [1-2] day). The majority of adolescents (57 [74.0%]) were treated with nonsteroidal anti-inflammatory drugs only, and 11 (14.3%) required no treatment. The highest reported incidence was observed among male adolescents aged 16 to 17 years after dose 2 (15.7 per 100 000; 95% CI, 9.7-23.9). Among those aged 16 to 17 years, the reporting rate was highest in those with a short (ie, ≤30 days) interdose interval (21.3 per 100 000; 95% CI, 11.0-37.2). Conclusions and Relevance: Results of this cohort study suggest that there was variation in the reported incidence of myocarditis or pericarditis after BNT162b2 vaccine among adolescent age groups. However, the risk of these events after vaccination remains very rare and should be considered in relation to the benefits of COVID-19 vaccination.

Epidemiology of Myocarditis and Pericarditis Following mRNA Vaccination by Vaccine Product, Schedule, and Interdose Interval Among Adolescents and Adults in Ontario, Canada.

Importance: Increased rates of myocarditis or pericarditis following receipt of COVID-19 mRNA vaccines have been observed. However, few available data are associated with differences in rates of myocarditis or pericarditis specific to vaccine products, which may have important implications for vaccination programs. Objective: To estimate rates of reported myocarditis or pericarditis following receipt of a COVID-19 mRNA vaccine by product, age, sex, dose number, and interdose interval. Design, Setting, and Participants: This population-based cohort study was conducted in Ontario, Canada (population: 14.7 million) from December 2020 to September 2021 and used data from Ontario's COVID-19 vaccine registry and passive vaccine-safety surveillance system. All individuals in Ontario, Canada, who received at least 1 dose of COVID-19 mRNA vaccine between December 14, 2020, and September 4, 2021, and had a reported episode of myocarditis or pericarditis following receipt of the COVID-19 vaccine during this period were included. We obtained information on all vaccine doses administered in the province to calculate reported rates of myocarditis or pericarditis. Exposures: Receipt of a COVID-19 mRNA vaccine (mRNA-1273 [Moderna Spikevax] or BNT162b2 [Pfizer-BioNTech Comirnaty]). Main Outcomes and Measures: All reports of myocarditis or pericarditis meeting levels 1 to 3 of the Brighton Collaboration case definitions were included. Rates and 95% CIs of reported cases of myocarditis or pericarditis per 1 000 000 mRNA vaccine doses administered were calculated by age, sex, dose number, vaccine product, and interdose interval. Results: Among 19 740 741 doses of mRNA vaccines administered, there were 297 reports of myocarditis or pericarditis meeting the inclusion criteria; 228 (76.8%) occurred in male individuals, and the median age of individuals with a reported event was 24 years (range, 12-81 years). Of the reported cases, 207 (69.7%) occurred following the second dose of the COVID-19 mRNA vaccine. When restricted to individuals who received their second dose during the period of enhanced passive surveillance (on or after June 1, 2021), the highest rate of myocarditis or pericarditis was observed in male individuals aged 18 to 24 years following mRNA-1273 as the second dose (299.5 cases per 1 000 000 doses; 95% CI, 171.2-486.4 cases per 1 000 000 doses); the rate following BNT162b2 as the second dose was 59.2 cases per 1 000 000 doses (95% CI, 19.2-138.1 cases per 1 000 000 doses). Overall rates for both vaccine products were significantly higher when the interdose interval was 30 or fewer days (BNT162b2: 52.1 cases per 1 000 000 doses [95% CI, 31.8-80.5 cases per 1 000 000 doses]; mRNA-1273: 83.9 cases per 1 000 000 doses [95% CI, 47.0-138.4 cases per 1 000 000 doses]) compared with 56 or more days (BNT162b2: 9.6 cases per 1 000 000 doses [95% CI, 6.5-13.6 cases per 1 000 000 doses]; mRNA-1273: 16.2 cases per 1 000 000 doses [95% CI, 10.2-24.6 cases per 1 000 000 doses]). Conclusions and Relevance: The findings of this population-based cohort study of Ontario adolescents and adults with myocarditis or pericarditis following mRNA COVID-19 vaccination suggest that vaccine products and interdose intervals, in addition to age and sex, may be associated with the risk of myocarditis or pericarditis after receipt of these vaccines. Vaccination program strategies, such as age-based product considerations and longer interdose intervals, may reduce the risk of myocarditis or pericarditis following receipt of mRNA vaccines.

Pandemic promises: Interrogating espoused data-informed decision-making

Abstract The depths of the impact of COVID-19 on nearly every aspect of our personal and professional lives was becoming painfully clear in May and June of 2020. While institutions of higher education had implemented crisis/emergency plans in the immediate onset of the pandemic, and largely extended those efforts into summer terms, the fall 2020 term loomed large. Institutional researchers were asked for myriad kinds of data and reports, ostensibly to inform executive leaders? decision-making regarding how to operate for the fall term. On its face, this fits with the current conceptualization of IR's work largely as decision support. Despite these requests, however, the question remains as to what was really driving decision-making about the fall. This research examined a random, representative sample of public statements regarding fall operations, often released in the name of a president or chancellor, to determine what factors these leaders espoused publicly as informing their fall plans.