Immune Responses to Coronaviruses with Emphasis in Children

Seasonal coronaviruses that cause innocent colds in children lead to the formation of antibodies that last for 1-3 years. One of the four seasonal coronaviruses, human coronavirus NL63 (HCoV-NL63), also uses ACE2 as a receptor [1,2]. This virus causes infection in the flu season. It is estimated that 5 % of influenza-like illness is due to NL63 [1,2]. The virus especially affects children and can cause bronchiolitis resulting often in hospitalizations [15-18]. Maternal antibodies seem to protect infants up to the age of three months, and most children seroconvert within the first 20 months of life [18].