The WHO alert, between June 2022 and March 2023 affected 15 children with 2 deaths: “Unusual growth of cases”
The reporting from the UK started on 5 April 2023. The National Ihr Focal Point informs the World Health Organization that it has been observed an increase since 2021 in severe myocarditis in newborns and infants associated with enterovirus infection. Between June 2022 and March this year, 15 infants and toddlers, aged up to 28 days, presented with a picture consistent with neonatal sepsis in Wales and south-west England. The PCR test related to 9 cases confirmed the presence of coxsackie B3 or coxsackie B4, enterovirus family. As of April 20, 3 patients were hospitalized, 4 were managed on an outpatient basis, and 2 had died.
Although enterovirus infections are common in infants and young children,”the reported increase in myocarditis with serious outcomes in infants and children associated with enterovirus infection is unusual“, notes the WHO. Ten cases of those described in this alert were registered in South Wales and 5 in Southwest England. Eight cases were treated in intensive care. Further details are awaited on the remaining 6, identified through a retrospective research.In all living patients examined myocarditis – inflammation of the heart muscle – was a feature of the conditions they presented with.The peak incidence of cases was in November 2022 (5 cases), while in the other months there were sporadic cases. Support from intubation to ventilation and circulatory support was required for the 8 patients admitted to the ICU. To get an idea of the unusual increase seen in the same hospital, covering the South Wales region, over the last 6 years only one other such case has been identified.
Enteroviruses can cause a variety of infectious diseases and are responsible for annual epidemics. They are usually mild, but have been found to affect newborns differently and often more severely than older children. There are multiple routes of transmission, particularly in the neonatal period. The alert reported to WHO concerns an increase in both the number and severity of enterovirus (coxsackievirus) infections in children under the age of one month. There is increased morbidity and mortality associated with the ongoing accident.
As for the countermeasures taken, on 28 February 2023 – informs the WHO – paediatricians in the South Wales region were alerted to the cases and were recommended to consider myocarditis in newborns and infants presenting with shock. A nationwide Incident Management Team has also been established and is reviewing the evidence gathered to determine next steps for the response. Epidemiological investigations are ongoing. UK authorities have raised awareness among healthcare workers about the cluster and asked them to be tested for enteroviruses in suspected cases. Hospital laboratories were reminded to send positive samples to the national reference laboratory for viral characterization and typing. Physicians and hospital laboratories to report suspected cases of neonatal enterovirus myocarditis identified since 1 June 2022 to the UK Health Security Agency.
Finally, WHO carried out a risk assessment. The UN health agency notes that preliminary investigations in the UK have not identified other clusters in any other region, in addition to the interested ones, in the last 12 months. Based on the limited information available, “WHO assesses the risk to public health as low”. However, because enterovirus is often not a notifiable disease in Member States, and because one characteristic is that one can be an asymptomatic carrier of the infection and spreader (in this series of cases there was little evidence of maternal infection before or during delivery), additional cases of severe neonatal enterovirus infections may not have been diagnosed or reported elsewhere.
In terms of recommendations, the WHO specifies that there is no specific antiviral therapy available and the treatment is aimed at preventing complications. There isn’t even a vaccine and control measures in cases of epidemics focus on classic hygiene measures (hand washing and disinfection of dirty clothes and surfaces). In certain situations, the agency points out, “it may be advisable to close nursery schools and schools to reduce the intensity of the transmission”. WHO does not recommend any travel or trade restrictions in the UK based on the information available. Please note that non-polio enteroviruses are common and distributed worldwide. And “although infections are often asymptomatic, others present as mild to moderate respiratory tract infections,” with symptoms such as fever, runny nose, and weakness. “Doctors seeing infants presenting with shock may consider a diagnosis of myocarditis and testing for enteroviruses.”