The United Kingdom has reported an unusual increase in myocarditis infections and two deaths in babies who had enterovirus infections, the World Health Organization (WHO) said yesterday.
In early April, the UK notified the WHO about an increase in severe myocarditis in infants in Wales. Fifteen cases consistent with neonatal sepsis in babies 28 days old and younger were reported from Wales and Southwest England from June 2022 and March 2023. Polymerase chain reaction (PCR) testing in nine patients confirmed either coxsackie B3 or coxsackie B4. As of April, three patients were hospitalized, four were receiving outpatient care, and two died.
The WHO said though enterovirus infections are common in young babies, the link to myocarditis with severe outcomes in the group is unusual. For comparison, in the hospital in South Wales that treated 10 of the cases only treated one similar case in the previous 6 years.
Myocarditis, or inflammation of the heart muscle, was the presenting feature, and cases peaked in November 2022, with sporadic cases reported across the other months. Enterovirus infections are typically mild, but they can be more severe in newborns than in older children.
An incident management team is reviewing all the evidence and has alerted UK authorities, who have raised awareness among health providers about the enterovirus cluster. Epidemiologic investigations are still under way. Also, clinicians published a letter detailing eight of the cases last month in BMJ.