This increase in cases of myocarditis (inflammation and damage to the heart) in very young babies in Wales is still being investigated, we are working with experts here and across the UK to try to understand this further.
Enterovirus is a common infection that spreads through the population every year, with larger outbreaks occurring regularly, often every three years.
Severe disease and myocarditis is a well-recognised complication of this infection, but is very rare. While there has been an increase in the number of cases in very young babies (under one month old), it still remains rare.