Early experience with myocarditis and pericarditis in adolescents following vaccination against COVID-19 in latvia

ABSTRACT

Background and Aim: The European Medicines Agency has approved mRNA vaccines developed by Pfizer/BioNTech and Moderna for the vaccination of adolescents against the SARS-CoV-2 infection. Cases of myocarditis and pericarditis have been described as rare postvaccination complications. We describe the Latvian experience with adolescents suffering from myocarditis following COVID-19 vaccination. Method(s) From June to December 2021 four cases consistent with postvaccination myocarditis were admitted to the Children's Clinical University Hospital, which is the only centre with special-ized paediatric cardiology care in Latvia. The Pfizer/BioNTech vaccine had been used in all. An ECG, Holter monitoring and ECHO was done, HS Troponin I levels checked, the most common infectious causes of myocarditis were excluded, and a cardiac MRI was performed in all cases. Result(s) Case 1 12-year-old girl, developed chest pain on postvac-cination day Nr 4 (PVD4) after the 1st dose. Holter monitoring revealed rare non-sustained ventricular tachycardia (NSVT), ECHO showed moderate mitral insufficiency, and a hyperecho-genic papillary muscle, troponin level peaked at 5339 pg/ml (PVD6), MRI (PVD 7) showed widespread myocardial oedema, transmural fibrosis. Symptoms resolved in 1 day, metoprolol suc-cinate and lisinopril were prescribed. Mitral insufficiency persists 5 months later. Case 2 15-year-old boy, developed chest pain after the 2nd dose on PVD2 and lasted for 7 days, he was admitted on PVD11 with a peak troponin level of 19pg/ml. MRI (PVD15) showed widespread myocardial oedema. Metoprolol succinate was prescribed. Case 3 15-year-old boy, developed chest pains on the day of the 1st dose and persisted for 35 days, he was admitted on PVD24 with peak troponin level 15ng/ml. MRI (PVD29) showed mild myocardial oedema, myocardial and pericardial fib-rosis. Case 4 13-year-old boy, developed chest pain on PVD2, which lasted for 65 days, he had an episode of syncope. Holter monitoring showed frequent PVCs, and NSVT, on PVD34 tro-ponin level was 2,5pg/ml. The child received a course of NSAIDs and was referred to us on PVD68. MRI (PVD69) revealed wide-spread myocardial oedema, fibrosis, and pericarditis. Methylprednisolone was given, and betaxolol was prescribed. Conclusion(s) Our case series show that some cases of postvaccination myocarditis develop complications requiring long-term treatment.