12f - Outbreak of myocarditis in children in Germany, 2024: Rare complication of parvovirus B19 or something new?
Fireside Abstracts
Information
Background : In July 2024, 4 children with myocarditis (aged 7–20 months) were admitted to one German hospital, 3 of whom died within 3 days. Parvovirus B19 (B19V) was detected in all 4 children, known to rarely cause myocarditis. We started investigating whether an outbreak of acute B19V-myocarditis occurred, locally or nationwide, and whether B19V virulence had increased.
Methods : Cases were defined as children (<18 years) with acute myocarditis and PCR-confirmed B19V infection in myocardium or blood with disease onset since 01.01.2024 in Germany. We descriptively analysed case data from the paediatric myocarditis registry MYKKE with cardiopathological analyses of endomyocardial biopsies. As a B19V-activity proxy, we analysed B19V notifications in one federal state where detection is notifiable. B19V virulence assessment of clinical specimens was initiated.
Results : The MYKKE registry showed an increase in B19V-myocarditis in 2024 compared to previous years, with 27 cases as of 26/08/2024 (median 2013–2023: 11 cases/year). There was only sporadic PCR co-detection of other routinely tested cardiotropic pathogens. Cases occurred nation-wide. Of cases with information available, 65% (17/26 cases) were <2 years old, 58% (15/26) were female, 85% (23/27) had histologically confirmed myocarditis, and 81% (21/26) occurred in April–July 2024. B19V-notification incidence in 2024 was 4.5-fold increased compared to the median incidence from 2016–2023, peaking in April 2024.
Conclusions : Investigations revealed a nation-wide increase of acute B19V-myocarditis, mainly affecting children <2 years of age. The strong post-pandemic B19V season may explain this myocarditis increase. Laboratory investigations on virulence are ongoing. B19V infection prevention is challenging, as it occurs pre-/asymptomatically. We have raised clinicians’ awareness via paediatric professional societies and the MYKKE registry to speed up patient referral and harmonise treatment options and thus improve clinical outcomes.
