The association of maternal SARS-CoV-2 vaccination-to-delivery interval and the levels of maternal and cord blood antibodies.
OBJECTIVE
To evaluate the correlation of maternal and cord blood levels of SARS-CoV-2 antibodies in pregnant women immunized against COVID-19.


METHODS
A prospective cohort study was performed of pregnant women who delivered at a single university affiliated tertiary medical center. Women who received the COVID-19 vaccine (BNT162b2 Pfizer©) were approached. The correlation between levels of maternal sera and umbilical cord SARS-CoV-2 specific IgG was assessed.


RESULTS
Overall, 58 women were included; of them, 19 had received a single dose and 39 received two doses of the COVID-19 vaccine. Positive levels of umbilical cord IgG were found in 13/19 (68.4%) and 38/39 (97.4%) women after the administration of a single dose and two doses of the vaccine, respectively. The levels of SARS-CoV-2 IgG antibodies in the maternal sera of vaccinated women were positively correlated to their respective concentrations in cord blood sera (ρ = 0.857; R2 linear = 0.719; P < 0.001). Thirteen days after vaccination, the ratio of maternal-to-umbilical cord anti Spike IgG antibodies was approximately 1, indicating relatively similar levels in maternal and cord sera.


CONCLUSION
After the SARS-CoV-2 vaccine, levels of maternal and cord blood antibodies were positively correlated, especially when tested after 13 days following administration of the first dose of the vaccine.
['Ben-Mayor Bashi|Tali|T|https://orcid.org/0000-0001-7182-6107', 'Amikam|Uri|U|', 'Ashwal|Eran|E|', 'Hershkovitz|Gal|G|', 'Attali|Emmanuel|E|', 'Berkovitz-Shperling|Roza|R|', 'Dominsky|Omri|O|', 'Halperin|Tami|T|', 'Goldshmidt|Hanoch|H|', 'Gamzu|Ronni|R|', 'Yogev|Yariv|Y|', 'Kuperminc|Michael|M|', 'Hiersch|Liran|L|']
SARS-COV-2 cord blood antibodies vaccination