Enterovirus Infection Reportedly Linked to Severe Myocarditis in Babies

On Apr. 5, 2023, the World Health Organization  (WHO) received information from the National IHR Focal Point (NFP) for the United Kingdom (U.K.) of an increase in severe myocarditis in infants believed to be associated with an enterovirus infection in Wales.¹ Enterovirus is a common pathogen that can cause respiratory illness, hand, foot and mouth disease and viral meningitis.² The WHO stated that although enterovirus infections are common and mild in infants, the surge in severe myocarditis being reported is unusual.³

Between June 2022 and April 2023, 10 infants under the age of 28 days reportedly were hospitalized in the U.K. for myocarditis, each having a positive enterovirus Polymerase Chain Reaction (PCR) test. Seven of the infants were treated in intensive care, and one case died before being transferred to tertiary care. All the cases presented sepsis, myocarditis, or cardiorespiratory arrest. The patients who were treated in intensive care were intubated, received ventilation and circulatory support.⁴

An additional five cases have been identified over the same period in the southwest of England, but there is no current information available on these cases.⁵

Medical Professionals Believe Myocarditis Cases are Rare

Although the U.K. does not have routine surveillance system to identify enterovirus-linked myocarditis, pediatricians have been asked to examine infants in intensive care to assess whether there is a broader outbreak of the virus.⁶

Dr. Paul Hunter, a professor in medicine at University of East Anglia, said:

The big problem with these types of cluster is knowing whether this represents a real change or a random clustering with little long term importance. Most but not all apparent clusters do not go onto pose a consequential threat to public health. Nevertheless, you cannot afford to assume that they will not progress and you have to investigate them.⁷

Dr. Penny Ward, a visiting professor in pharmaceutical medicine at Kings College London said there is a possibility that there is a change in the pathogenicity of the enterovirus found in the recent cases, which is to be investigated by public health officials. She stated:

It is quite possible that the uptick in myocarditis cases was driven by a larger scale outbreak of enterovirus infections–as we have seen quite a number of viral infections increased in frequency since COVID-19 became less of a problem, but as we do not routinely look for these viruses in the population at large it’s difficult to know.⁸

Parents of 12-Day Old Boy Told His Death Was “A One Off”

Joann and Christian Edward’s 12-day-old son Elijah died from myocarditis and similar circumstances on Mar. 19, 2022, prior to when the situation became a public health concern in the U.K. They were told that their son’s death was “a one off” and a “very unlucky case.” Later, Elijah’s parents read news reports about a cluster of similar cases among other newborns being investigated. Fourteen months after their son’s death, Elijah’s parents were told that his case would not form part of the investigation of the cases that occurred during June 2022 to April 2023.⁹

No Specific Antiviral Therapy Available for Enterovirus Infections

Currently, there are no specific antivirals available on the market for enterovirus infections. The treatment protocol for symptoms focuses on using traditional infection control measures to prevent further complications. The WHO stated:

As there is no vaccine for this virus, control measures during outbreaks are focused on classical hygiene measures including frequent hand washing and disinfection of soiled clothing and surfaces. In certain situations, it may be advisable to close child-care facilities and schools to reduce the intensity of transmission.¹⁰

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