Short- and long-term outcomes of cardiac adverse events following COVID-19 immunization managed in a Canadian pediatric center.

BACKGROUND

Numerous reports have described the clinical presentation of cardiac adverse events following immunization (AEFI) with COVID-19 vaccines but long-term outcome studies are limited, especially in the pediatric population.

METHODS

This is a single center retrospective case series of pediatric patients with cardiac AEFI following the Pfizer/BioNTech mRNA COVID-19, diagnosed between May 2021 and May 2022, and managed following a standardized protocol. Follow up information is presented up to 12 months post diagnosis. The incidence rate of cardiac AEFI was estimated for Ottawa residents.

RESULTS

All cases were male (N = 17) with an average age of 16 years (range = 12-17). The majority of cases occurred after the 2nd (12/17) or 3rd vaccine dose (4/17) and were manifested mostly as myopericarditis (15/17). Average interval between the 1st and 2nd vaccine (n = 12) doses was 38 days (21-69 days). All patients improved promptly on non-steroidal anti-inflammatory drugs without recurrence. Five patients reported negative impact on quality of life and mental health, including 2 cases that led to new vaccine hesitancy, not only to COVID-19 vaccine, but also to other routine vaccines. The rate of cardiac AEFI was estimated for residents of the city of Ottawa and found to be 12.01 cases (CI 90 5.98-21.68) per 100,000 doses following the 2nd dose and 16.56 cases (CI 90 5.66-37.90) per 100,000 doses following the 3rd dose for males aged 12 to 17 years.

CONCLUSIONS

Twelve months following the AEFI, all patients clinically recovered from their myopericarditis, but some reported negative impact on quality of life and mental health, including new vaccine hesitancy. This highlights the importance for timely and systematic evaluation of AEFI and the need to provide support, follow up and vaccine counseling in individuals experiencing an AEFI.