Antibody titre in infants of covid-19 infected mothers

Abstract

COVID‐19 is caused by SARS‐CoV‐2 and spreads from person‐to‐person. Pregnant women continued to be vulnerable to COVID‐19. Infant protection from covid-19 infection is primarily dependent on neonatal innate immune responses and maternally derived, transplacentally acquired antibodies. Our aim was to study trans placental passage of anti-SARS-CoV-2 antibody and the magnitude of natural passive immunity in infants born to mothers with covid 19. Prospective observational study was conducted at Balchikitsalay of MBGH, RNT medical college, Udaipur, Rajasthan from June 2021 to December 2022. Mothers with history of covid-19 positive in past at time of delivery in our hospital[MBGH] and all infants [0 days to 12 months] delivered from covid positive mothers who fulfill inclusion and exclusion criteria were enrolled in study. Measurement of SARS Cov2 antibody titre (serum IgG) in mothers and infants at our central lab where this sample was analysed by electrochemiluminescence. Total 100 covid-19 positive mothers and their infants who fulfill inclusion and exclusion criteria were enrolled in study. Out of 100 infants, 59% were males and 41% were females. Out of 100 infants, 12 (12%) were found in age group of <=3 months, followed by 32 (32%) in 4-6 months age group, 32 (32%) in 7-9 months and 24 (24%) in 10 -12 months age group. In our study 100 infants had different antibody titre level at different age. In Age group <= 3 months had maximum mean value of Antibody titre 135 AU/ml , followed by 26.5 AU/ml in Age group 4-6months ,then 2.5 AU/ml in age group 7-9 months, and 0.5 AU/ml in age group 10-12 months. Antibody titre value sharply fall after birth and antibody titre remain almost one tenth of birth, after age of 3 month. After 6 month of age, it fall below protective level (10 Au/ml). In our study protective value of antibody titre remain till 6th month of age, after that antibody titre decline below protective value. So we recommended that vaccination against covid-19 should be started after 6th month of life like other influenza virus