May 12, 2021

Passive and Active Immunity in Infants Born to Mothers with SARS-CoV-2 Infection during Pregnancy: Prospective Cohort Study

Category: Article Summary

Topic: Vaccines and Immunity

Keywords (Tags): immunity, pregnancy

• [Pre-print, not peer-reviewed] In a cohort of US mothers testing positive for SARS-CoV-2 during pregnancy (n=145), anti-SARS-CoV-2 antibodies were detected in 65% and 58% of maternal and cord blood samples at delivery, respectively. The IgG transplacental transfer ratio was significantly higher among women receiving their first maternal positive PCR test 60-180 days before delivery compared to those receiving their first test <60 days before delivery (ratio 1.2 vs 0.6). Infants were followed with serial serologic analysis and 2 of 147 infants seroconverted (defined as high levels of IgG and IgM) by as early as 2 weeks, including one premature infant with confirmed intrapartum infection. IgG antibody levels in the infants correlated with IgG levels in the cord blood. In infants with maternally derived antibody, 8% (4 of 48) became undetectable at 1-4 weeks and 38% (5 of 14) were undetectable by 13-28 weeks, with some antibodies persisting up to 6 months of age. 

Song et al. (May 3, 2021). Passive and Active Immunity in Infants Born to Mothers with SARS-CoV-2 Infection during Pregnancy: Prospective Cohort Study. Pre-print downloaded May 12 from https://doi.org/10.1101/2021.05.01.21255871