SARS-CoV-2 mRNA Vaccination-Associated Myocarditis in Children Ages 12-17: A Stratified National Database Analysis

Abstract

Objectives: Establishing the rate of post-vaccination cardiac myocarditis in the 12-15 and 16-17-year-old population in the context of their COVID-19 hospitalization risk is critical for developing a vaccination recommendation framework that balances harms with benefits for this patient demographic. Design, Setting and Participants: Using the Vaccine Adverse Event Reporting System (VAERS), this retrospective epidemiological assessment reviewed reports filed between January 1, 2021, and June 18, 2021, among adolescents ages 12-17 who received mRNA vaccination against COVID-19. Symptom search criteria included the words myocarditis, pericarditis, and myopericarditis to identify children with evidence of cardiac injury. The word troponin was a required element in the laboratory findings. Inclusion criteria were aligned with the CDC working case definition for probable myocarditis. Stratified cardiac adverse event (CAE) rates were reported for age, sex and vaccination dose number. A harm-benefit analysis was conducted using existing literature on COVID-19-related hospitalization risks in this demographic. Main outcome measures: 1) Stratified rates of mRNA vaccine-related myocarditis in adolescents age 12-15 and 16-17; and 2) harm-benefit analysis of vaccine-related CAEs in relation to COVID-19 hospitalization risk. Results: A total of 257 CAEs were identified. Rates per million following dose 2 among males were 162.2 (ages 12-15) and 94.0 (ages 16-17); among females, rates were 13.0 and 13.4 per million, respectively. For boys 12-15 without medical comorbidities receiving their second mRNA vaccination dose, the rate of CAE is 3.7-6.1 times higher than their 120-day COVID-19 hospitalization risk as of August 21, 2021 (7-day hospitalizations 1.5/100k population) and 2.6-4.3-fold higher at times of high weekly hospitalization risk (2.1/100k), such as during January 2021. For boys 16-17 without medical comorbidities, the rate of CAE is currently 2.1-3.5 times higher than their 120-day COVID-19 hospitalization risk, and 1.5-2.5 times higher at times of high weekly COVID-19 hospitalization. Conclusions: Post-vaccination CAE rate was highest in young boys aged 12-15 following dose two. For boys 12-17 without medical comorbidities, the likelihood of post vaccination dose two CAE is 162.2 and 94.0/million respectively. This incidence exceeds their expected 120-day COVID-19 hospitalization rate at both moderate (August 21, 2021 rates) and high COVID-19 hospitalization incidence. Further research into the severity and long-term sequelae of post-vaccination CAE is warranted. Quantification of the benefits of the second vaccination dose and vaccination in addition to natural immunity in this demographic may be indicated to minimize harm.

Myocarditis and Pericarditis following COVID-19 Vaccination: Rapid Systematic Review of Incidence, Risk Factors, and Clinical Course

“…34 44 47-50 53-56 and three case series compiled from publicly available websites (Public Health Agency of Canada, PHAC; UK's Medicines & Healthcare Products Regulatory Agency [Yellow Card database], UK;…”

Myocarditis and Pericarditis following COVID-19 Vaccination: Evidence Syntheses on Incidence, Risk Factors, Natural History, and Hypothesized Mechanisms

“…Forty-six studies were included in this update ( Figure 1 ). Findings from 12 studies from the original review 15 were carried forward (Q1=5 25–29 , Q2=2 29 30 , Q3b. 25–28 31–36 ).…”

“…Findings from 12 studies from the original review 15 were carried forward (Q1=5 25–29 , Q2=2 29 30 , Q3b. 25–28 31–36 ). From the search update, we identified 34 new reports across all questions (Q1=9 37–45 , Q2=5 37 41 45–47 , Q3=1 48 , Q4=3 39 49 50 , Q5=21 9 51–70 ); we excluded five studies that only reported on combined myo- and/or pericarditis (as we located other studies with these reported separately), 71–75 eight studies that did not report on confirmed cases, 76–83 and three studies 84–86 that did not contribute additional data to other included studies on the same cases.…”

“…From the original review, we report on 10 case series (6 published as case series [31][32][33][34][35][36] and 4 included in Q1 but having relevant data on cases [25][26][27][28] ) reporting on a total of 10,264 cases (median 22, range 6-5611) of myocarditis or pericarditis. All reports except the one using EudraVigilance data from the European Economic Area included clinician-confirmed cases.…”

The controversy surrounding vaccination of young people against COVID‐19

“…Given that new data from campaigns with several millions of vaccinated children have emerged, potential risks of rare but serious adverse reactions following vaccination for this age group can now be quantified more reliably. A study from the USA, 2 posted as a preprint on 30 August found that the risk of myocarditis within 5 days of the second dose of the vaccine is 2–6 times higher than the 120‐day risk of hospitalisation in boys 12–17 without underlying medical conditions. An article from Israel 3 published on 25 August 2021, involving almost one million vaccinated persons above 16 years of age, has concluded that vaccination was most strongly associated with an elevated risk of myocarditis (RR 3.24; 95% CI 1.55,12.44); the median age of persons with myocarditis was 25 years and 90.9% were male.…”