HHV-6, enterovirus and parvovirus B-19 DNA found in the blood of immunocompetent infants with myocarditis

80% of immunocompetent infants with myocarditis were positive for a cardiotropic virus compared to less than 4% of healthy controls, according to a multicenter study led by researchers at Washington University in St. Louis. This was a far higher rate than in older children.

Out of the 21 patients, 9 (43%) demonstrated positive blood viral PCR results: 4 were positive for enterovirus, 2 for parvovirus B19, 1 for adenovirus, and 2 for HHV-6. Most of the positive patients (89%) were less than 12 months old at the time of testing compared to 9% of children older than 12 months tested positive for viral DNA.

This is the first study to demonstrate an age-specific difference of viral DNAemia in pediatric patients with clinical myocarditis. While the reason for this age difference is unclear, the authors speculate that it may be because the relative immaturity of the immune system in infants results in an increased rate of DNAemia. The authors raise the issue of whether targeted anti-viral therapy may be beneficial in infants with myocarditis.

Read the full paper: Simpson 2015