Clinical course and follow-up of pediatric patients with COVID-19 vaccine-associated myocarditis compared to non-vaccine-associated myocarditis within the prospective multicenter registry-"MYKKE"

Am Heart J. 2024 Jan:267:101-115. doi: 10.1016/j.ahj.2023.11.006. Epub 2023 Nov 11.

Abstract

Background: Since the onset of widespread COVID-19 vaccination, increased incidence of COVID-19 vaccine-associated myocarditis (VA-myocarditis) has been noted, particularly in male adolescents.

Methods: Patients <18 years with suspected myocarditis following COVID-19 vaccination within 21 days were enrolled in the PedMYCVAC cohort, a substudy within the prospective multicenter registry for pediatric myocarditis "MYKKE." Clinical data at initial admission, 3- and 9-months follow-up were monitored and compared to pediatric patients with confirmed non-vaccine-associated myocarditis (NVA-myocarditis) adjusting for various baseline characteristics.

Results: From July 2021 to December 2022, 56 patients with VA-myocarditis across 15 centers were enrolled (median age 16.3 years, 91% male). Initially, 11 patients (20%) had mildly reduced left ventricular ejection fraction (LVEF; 45%-54%). No incidents of severe heart failure, transplantation or death were observed. Of 49 patients at 3-months follow-up (median (IQR) 94 (63-118) days), residual symptoms were registered in 14 patients (29%), most commonly atypical intermittent chest pain and fatigue. Diagnostic abnormalities remained in 23 patients (47%). Of 21 patients at 9-months follow-up (259 (218-319) days), all were free of symptoms and diagnostic abnormalities remained in 9 patients (43%). These residuals were mostly residual late gadolinium enhancement in magnetic resonance imaging. Patients with NVA-myocarditis (n=108) more often had symptoms of heart failure (P = .003), arrhythmias (P = .031), left ventricular dilatation (P = .045), lower LVEF (P < .001) and major cardiac adverse events (P = .102).

Conclusions: Course of COVID-19 vaccine-associated myocarditis in pediatric patients seems to be mild and differs from non-vaccine-associated myocarditis. Due to a considerable number of residual symptoms and diagnostic abnormalities at follow-up, further studies are needed to define its long-term implications.

Publication types

  • Multicenter Study

MeSH terms

  • Adolescent
  • COVID-19 Vaccines* / adverse effects
  • COVID-19* / complications
  • COVID-19* / epidemiology
  • COVID-19* / prevention & control
  • Child
  • Contrast Media
  • Disease Progression
  • Female
  • Follow-Up Studies
  • Gadolinium
  • Heart Failure* / complications
  • Humans
  • Male
  • Myocarditis*
  • Prospective Studies
  • Registries
  • Stroke Volume
  • Ventricular Function, Left

Substances

  • Contrast Media
  • COVID-19 Vaccines
  • Gadolinium