MMWR: Open Access: COVID-19 Vaccine Safety in Children Aged 5–11 Years — United States, November 3–December 19, 2021

From Discusssion:

My take: Cardiac complications related to COVID-19 appear to be much more likely than adverse cardiac events due to vaccination.

Related blog post: Vaccination Reduces Risk of COVID-19 Associated MIS-C & New Quarantine Guidelines