Parvovirus B19-associated myocarditis in children: A systematic review of clinical features, management and outcomes.

Abstract

<h4>Background</h4>Parvovirus B19 (PVB19) has emerged as a relevant etiologic agent of paediatric myocarditis, particularly during recent epidemiological surges in Europe and the United States. Despite increasing recognition, current knowledge remains fragmented, and standardised diagnostic and therapeutic strategies are lacking.<h4>Methods</h4>We conducted a systematic review of the literature up to May 2025, including 40 studies encompassing 53 individual case reports, 107 patients from registry-based cohorts, and 4 tissue-based investigations.<h4>Results</h4>Clinical presentation was frequently fulminant, with cardiogenic shock, severe left ventricular dysfunction, and need for mechanical circulatory support in up to 47% of cases. Mortality rates ranged from 10% to 30%, with heart transplantation rates varying between 5% and 42% across cohorts. Diagnosis relied primarily on blood polymerase chain reaction (PCR), while serology showed limited diagnostic utility. Histological confirmation via endomyocardial biopsy (EMB) was variably applied across studies, and myocardial viral load quantification was reported in only one study. Case series and cohort studies confirmed early age of onset (median 16-24 months), respiratory or gastrointestinal prodromes, and poor outcomes in fulminant presentations. Tissue-based studies revealed high myocardial PVB19 loads in acute myocarditis, particularly in infants, but also demonstrated viral persistence in asymptomatic individuals, complicating causal inference. Immunomodulatory therapy was administered in up to 58% of cases, although its clinical impact remains uncertain due to heterogeneity in treatment protocols. No antiviral treatments have been evaluated to date.<h4>Conclusion</h4>These findings highlight the need for standardised diagnostic criteria incorporating PCR, serology, imaging, and, where appropriate, EMB and viral load assessment. Given recent epidemiologic surges and high morbidity, prospective multicentre studies and surveillance efforts are urgently required to refine clinical algorithms and improve outcomes in paediatric PVB19 myocarditis.