Observational studyVaccine2022
Background incidence rates of adverse events of special interest related to COVID-19 vaccines in Ontario, Canada, 2015 to 2020, to inform COVID-19 vaccine safety surveillance.
Observational study in Vaccine, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 14 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
14 citing papers in PubMed, 1 synthesis or guideline pooled it, 26 citations in OpenAlex.
- COVID-19 vaccination and carditis in children and adolescents: a systematic review and meta-analysis.Clinical research in cardiology : official journal of the German Cardiac Society · 2022Pooled it
- Observed Versus Expected Analysis-How Does It Fit in the Pharmacovigilance Toolkit?Drug safety · 2025Review
- A Bayesian network analysis of the Pfizer COVID-19 vaccine in the paediatric population.NPJ vaccines · 2025Article
- Safety and health care utilization following COVID-19 vaccination (BNT162b2) among children and youth with juvenile idiopathic arthritis and inflammatory bowel disease: A population-based study.Paediatrics & child health · 2025Article
- The use of observed-to-expected analyses as a signal detection tool in COVID-19 vaccine safety surveillance: lessons learned from an industry perspective.Frontiers in drug safety and regulation · 2025Review
- Background incidence rates from electronic healthcare databases for vaccine safety monitoring: review of challenges from the COVID-19 vaccination campaign and proposal for best practices.Frontiers in drug safety and regulation · 2025Article
- COVID-19 vaccination safety and associated health care utilization among adults with inflammatory bowel disease - a population-based self-controlled case series analysis.BMC gastroenterology · 2024Article
- Exploring the reported adverse effects of COVID-19 vaccines among vaccinated Arab populations: a multi-national survey study.Scientific reports · 2024Article
- Article
- Impact of infections on the incidence of acute inflammatory demyelinating polyneuropathy in children.Annals of the Child Neurology Society · 2023Article
- Background incidence rates of selected adverse events of special interest (AESI) to monitor the safety of COVID-19 vaccines.Vaccine · 2023Article
- COVID-19 Vaccines and Myocarditis: An Overview of Current Evidence.Biomedicines · 2023Review
- Myocarditis or Pericarditis Events After BNT162b2 Vaccination in Individuals Aged 12 to 17 Years in Ontario, Canada.JAMA pediatrics · 2023Article
- Data resource profile: COVid VAXines effects on the aged (COVVAXAGE).International journal of population data science · 2023Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
8 authors at 3 institutions in 1 country.
Funding
Abstract
backgroundBackground incidence rates are critical in pharmacovigilance to facilitate identification of vaccine safety signals. We estimated background incidence rates of 11 adverse events of special interest related to COVID-19 vaccines in Ontario, Canada.
methodsWe conducted a population-based retrospective observational study using linked health administrative databases for hospitalizations and emergency department visits among Ontario residents. We estimated incidence rates of Bell's palsy, idiopathic thrombocytopenia, febrile convulsions, acute disseminated encephalomyelitis, myocarditis, pericarditis, Kawasaki disease, Guillain-Barré syndrome, transverse myelitis, acute myocardial infarction, and anaphylaxis during five pre-pandemic years (2015-2019) and 2020.
resultsThe average annual population was 14 million across all age groups with 51% female. The pre-pandemic mean annual rates per 100,000 population during 2015-2019 were 191 for acute myocardial infarction, 43.9 for idiopathic thrombocytopenia, 28.8 for anaphylaxis, 27.8 for Bell's palsy, 25.0 for febrile convulsions, 22.8 for acute disseminated encephalomyelitis, 11.3 for myocarditis/pericarditis, 8.7 for pericarditis, 2.9 for myocarditis, 2.0 for Kawasaki disease, 1.9 for Guillain-Barré syndrome, and 1.7 for transverse myelitis. Females had higher rates of acute disseminated encephalomyelitis, transverse myelitis and anaphylaxis while males had higher rates of myocarditis, pericarditis, and Guillain-Barré syndrome. Bell's palsy, acute disseminated encephalomyelitis, and Guillain-Barré syndrome increased with age. The mean rates of myocarditis and/or pericarditis increased with age up to 79 years; males had higher rates than females: from 12 to 59 years for myocarditis and ≥12 years for pericarditis. Febrile convulsions and Kawasaki disease were predominantly childhood diseases and generally decreased with age.
conclusionsOur estimated background rates will permit estimating numbers of expected events for these conditions and facilitate detection of potential safety signals following COVID-19 vaccination.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.