Seroepidemiology of echovirus 30 in Korean children

Background: Although aseptic meningitis associated with echovirus type 30 has emerged as a global public health concern, no data have been reported on Children’s immune status against echovirus type 30. The current study aimed to investigate the seropositivity among Korean children for antibodies against echovirus 30. Methods: Two hundred and fifty residual serum samples were collected at St. Paul’s Hospital. Individuals were categorized by age into four groups: group 1 (3 months–2 years), group 2 (3–6 years), group 3 (7–10 years) and group 4 (11–15 years). Neutralizing antibodies against echovirus 30 were measured. Results: Seroprotective neutralizing antibodies against echovirus 30 were detected in 129 (49%) individuals. Seropositivity rates were 23%, 48%, 55% and 73% in groups 1–4, respectively. For antibody titers, 1:256–1:512 was the highest neutralizing antibody titer range in group 2, while 1:1024–1:2048 in group 3 and 4. Among the seropositive individuals in group 3 and 4, 6% and 12% had neutralizing antibody titers of 1:2048, respectively. Conclusions: The seropositivity rate increased significantly with age. The distribution of neutralizing antibody titers varied by age group, and higher ranges of neutralizing antibody titers were observed in higher age groups. These findings suggest high susceptibility to echovirus 30 infection in children younger than 2 years old. Echovirus 30 infection in childhood may have contributed to increased neutralizing antibody titers with age.