Recent Increase in Parvovirus B19 Myocarditis in Children with Severe Heart Failure—Observational Data from the Multicenter Registry for Pediatric Myocarditis “MYKKE”

Background: Myocarditis is a rare complication of infection with Parvovirus B19 (B19V). In the postpandemic era, the incidence of B19V peaked across Europe, particularly from March to May 2024. Concurrently, a nationwide increase in pediatric hospitalizations due to B19V myocarditis with severe outcomes was observed. To investigate the incidence and clinical characteristics of B19V myocarditis since the latter half of 2023, we utilize data from the multicenter registry “MYKKE,” in collaboration with the Robert Koch Institute.

Methods: “MYKKE” as a multicenter, prospective registry for pediatric myocarditis with 31 participating centers in Germany, Austria, and Switzerland, and was used as a study platform. Clinical data from patients with myocarditis and PCR-confirmed detection of B19V in the myocardium and/or blood were collected and descriptively analyzed.

Results: From August 2023 to September 2024, 40 out of 159 (25%) registered patients were diagnosed with B19V myocarditis and enrolled by 14 participating centers. In comparison, the number of B19V myocarditis cases during the pandemic years (2020–2022) was six, seven, and four cases per year, respectively. Over the prepandemic registry period (2013–2019), the median number of B19V myocarditis cases was 12 cases per year. Patients diagnosed with B19V myocarditis during the observation period were notably young, with a median age of 1.8 (IQR 1.4–3.6) years, compared with a median age of 11.4 (IQR 1.5–15.1) years in the previous years. Sixty percent were female (22/37, in 3 cases unknown sex). Most cases were enrolled between April and July 2024 (65%, 26/40). The endomyocardial biopsy (EMB) revealed acute/subacute myocarditis in 87% (26/30) of the patients, while chronic/healing myocarditis was found in 10% (3/30). EMB was not performed in two cases, and data for eight patients are still pending. Patients with B19V myocarditis had a particularly severe disease course, with a median left ventricular ejection fraction (LVEF) of 25 (IQR 20–35)% at initial admission, compared with a median LVEF of 48 (IQR 29–55)% in patients without B19V detection. Ten patients (25%) required mechanical circulatory support, and one patient died.

Conclusion: Data from the multicenter “MYKKE” registry reveal a marked increase in pediatric cases of B19V myocarditis in 2023/2024 compared with previous years. The affected cohort was notably young and displayed a particularly severe disease course. These findings reinforce the need for heightened awareness and targeted interventions. Further investigation into the underlying factors driving this increased incidence and severe presentation is warranted.

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Artikel online veröffentlicht:
11. Februar 2025