Dynamics of formation of anti- bodies to SARS-CoV-2 after coronavirus infection in children

Abstract

Objective. To estimate the level of antibodies to SARS-CoV-2-IgM and SARS-CoV-2-IgG in children with COVID-19 in acute period and during 1 year period of follow-up after coronavirus infection.
 Materials and methods. Blood samples for the presence of IgM and IgG antibodies to SARS-CoV-2 were analyzed in 119 children aged 11.0 [10.1; 11.2] with COVID-19 in the acute period (29.4 % asymptomatic, 51.3 % mild and 19.3 % moderate), and SARS–CoV-2-IgG in the dynamics of the follow-up after 1 (n=55), 6 (n=33) and 12 (n=32) months from the moment of discharge from the hospital in a prospective cohort study. The levels of SARS-CoV-2 surface glycoprotein S, including the receptor-binding domain – RBD were measured at different time by using enzyme-linked immunosorbent assay.
 Results. The level of IgM positive rate for SARS-CoV-2 was initially negative in 86.6 % of children with COVID-19. The original seroconversion (on admission to the hospital) was 38.7 % and it increased to 96.7 % in 1 month and to 100 % in 12 months of observation. There were no statistically significant differences in IgG persistence depending on the age and course of COVID-19.
 Conclusions. The new coronavirus infection causes a long-term response of IgG antibodies to SARS-CoV-2 which persists for one year of observation and increases by 12 months after the infection regardless of the severity of COVID-19.