Elasomeran

Author Information

An event is serious (based on the ICH definition) when the patient outcome is:

• * death

• * life-threatening

• * hospitalisation

• * disability

• * congenital anomaly

• * other medically important event

A 38-year-old woman developed vaccine-induced immune-mediated thrombocytopenia (ITP) and myocarditis following the administration of elasomeran against COVID-19.

The woman was admitted to the emergency department because of chest pain, mild dyspnoea and sweating. The first dose of elasomeran [mRNA-1273 vaccine; Moderna, Cambridge, MA, USA; dosage and route not stated] was administered against COVID-19 4 days before symptom onset. Electrocardiography showed ventricular bigeminy and ST elevation in augmented vector right with co-existent multi-lead ST depression. Creatinine kinase-MB (CK-MB) was initially normal; however, troponin T was elevated. CK-MB and troponin T levels continued to rise till the following morning after symptom onset. On echocardiography, cardiac function was normal, and regional wall motion abnormalities and myocardial oedema were not observed. Moreover, laboratory tests showed that the platelet level was reduced from 283 × 10 ⁹ cells/L measured 5 months ago to 9 × 10 ⁹ cells/L at the time of admission. However, no ecchymosis, purpura, or spontaneous bleeding due to thrombocytopenia was noted. Coronary angiography was performed because of elevated cardiac enzymes and abnormal electrocardiogram findings. No coronary artery stenosis was observed on angiography, and cardiac enzymes started to show a gradual downward trend 1 day after admission. However, the platelet count did not improve even after 3 days of follow-up. Therefore, on day 3 of admission, immune globulin was administered. The platelet count measured after the first day of immune globulin administration showed an upward trend; however, immune globulin was stopped after only 2 days because she complained of severe headache [aetiology not stated] during immune globulin administration. Endomyocardial biopsy was not performed initially because of thrombocytopenia. After immune globulin administration, biopsy was performed on day 5 of admission when the platelet count had increased to 50 × 10 ⁹ cells/L. As for the pathological findings of myocardial tissue, internal nuclei and vacuolated muscle fibers were observed, and lymphohistiocytic infiltrates between muscle fibers were observed. These findings showed myocarditis in the stage of recovery. Cardiac magnetic resonance (CMR) was performed to confirm the diagnosis and assess the degree of myocardial damage. In CMR, multifocal patchy delayed enhancement at mid of anterior-inferoseptal wall of left ventricle (LV) and subendocardial wall of anterior-inferoseptal wall of LV basal to mid wall was observed. Also, in the T2 image of CMR, high signal intensity at anterior-inferoseptal wall of LV basal to mid wall was observed. These findings were judged to be those found in myocarditis. She was discharged on day 6 of admission. Results of anti-heparin platelet factor 4 antibody test performed during hospitalisation were negative. Considering her history and clinical course, it was concluded that myocarditis and ITP seemed to have occurred simultaneously after elasomeran vaccination.