Maternal IgG Antibodies to SARS-CoV-2 Transferred Across Placenta

MONDAY, Feb. 1, 2021 (HealthDay News) — Maternal immunoglobulin (Ig)G antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are transferred across the placenta, and cord blood IgG concentrations are associated with maternal IgG concentrations, according to a study published online Jan. 29 in JAMA Pediatrics.

Dustin D. Flannery, D.O., from the Children’s Hospital of Philadelphia, and colleagues examined the correlation between maternal and neonatal SARS-CoV-2-specific antibody concentrations in a cohort study involving 1,714 women who delivered between April 9 and Aug. 8, 2020. Antibody measurements were taken from maternal and cord blood sera for 1,471 mother/newborn dyads.

The researchers detected SARS-CoV-2 IgG and/or IgM antibodies in 83 of 1,471 women (6 percent) at the time of delivery; in 72 of 83 newborns (87 percent), IgG was detected in cord blood, while IgM was not detected in any cord blood specimens. No antibodies were detected in infants born to seronegative mothers. Eleven infants born to seropositive mothers were seronegative, including five born to mothers with IgM antibodies only and six born to mothers with significantly lower IgG concentrations compared with mothers of seropositive infants. There was a positive correlation for cord blood IgG concentrations with maternal IgG concentrations. Women with asymptomatic SARS-CoV-2 infections and those with mild, moderate, and severe COVID-19 had placental transfer rates of more than 1.0.

“Our findings demonstrate the potential for maternally derived antibodies to provide neonatal protection from SARS-CoV-2 infection and will help inform both neonatal management guidance and design of vaccine trials during pregnancy,” the authors write.

One author disclosed financial ties to the pharmaceutical industry.

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