Cord blood antibody following maternal SARS-CoV-2 inactive vaccine (CoronaVac) administration during the pregnancy.

Maternal vaccination with SARS-CoV-2 vaccines has not been well studied yet in terms of safety and efficacy for protecting the newborn by the placental passage of antibodies. We reported 34 years of old health care worker (HCW) without any known SARS-CoV-2 infection. She had the first dose of SARS-CoV-2 inactivated virus vaccine (CoronaVac, Sinovac Life Science Co, Ltd, Beijing, China) at a gestational age of 28 weeks. The second dose of vaccine was given four weeks later at a gestational age of 32 weeks. HCW did not report any vaccine-related adverse events after either the first or second dose of the vaccine. Three weeks after the second dose of the vaccine, her anti-receptor-binding domain (RBD) of SARS-CoV-2 spike protein antibody was 779 arbitrary units (AU) per ml. She gave a birth of 38 weeks three days gestation age of healthy, full-term girl with a birth weight of 2770 gr. The mother's anti-RBD antibody was 734 AU/ml, the infant's cord blood anti-RBD antibody level was 764 AU/ml, respectively, cord sera/maternal sera transfer ratio was 1,04. This infant is the first identified case of SARS-CoV-2 IgG antibodies detectable in cord blood after maternal vaccination with CoronaVac.