Human coronavirus NL63 and 229E seroconversion in children.

Area of Science:

• Virology
• Immunology
• Epidemiology

Background:

• Human coronavirus NL63 (HCoV-NL63), identified in 2004, is a global pathogen.
• HCoV-NL63 and the related HCoV-229E can cause severe illness in vulnerable populations, including young children.

Purpose of the Study:

• To determine the age of first-time HCoV-NL63 infection and seroconversion in children.
• To compare HCoV-NL63 seroconversion rates with those of HCoV-229E.

Main Methods:

• Developed recombinant HCoV-229E and HCoV-NL63 nucleocapsid protein enzyme-linked immunosorbent assays (ELISAs).
• Conducted a seroepidemiology survey using longitudinal (13 newborns over 18+ months) and cross-sectional (139 children aged 0-16 years) serum samples.

Main Results:

• Maternal antibodies against both viruses were present at birth and waned within 3 months.
• In longitudinal study, 7/13 children seroconverted to HCoV-NL63, while 2/13 seroconverted to HCoV-229E.
• Cross-sectional data showed 75% and 65% of children aged 2.5-3.5 years were seropositive for HCoV-NL63 and HCoV-229E, respectively.

Conclusions:

• Seroconversion to HCoV-NL63 and HCoV-229E typically occurs before 3.5 years of age.
• Early childhood exposure to these common coronaviruses is widespread.