COVID-19 Infection Alters Pregnant Mothers’ and Their Newborns’ Immunity

In a study conducted at the Cleveland Clinic that sought to understand the clinical and immunological implications of COVID-19 on maternal-to-fetal health, investigators found COVID-19 infection altered the mothers’ immunity at delivery, and gestational COVID-19 exposure alters the immunity of newborns.

The study included 93 mothers with COVID-19 and 45 of their infants who were exposed to the virus. Investigators compared maternal blood specimens collected close to the original date of COVID-19 infection and throughout pregnancy and delivery, as well as studied immune profiles for more than 1,400 cytokines and other inflammatory proteins from the subjects’ peripheral and cord blood samples. At delivery, the women had dysregulated levels of many cytokines associated with pregnancy complications such as MMP7, MDK, ESM1, BGN and CD209. The infants expressed induction of T cell-associated cytokines IL33, NFATC3 and CCL21. While most births were healthy, there were high incidents of certain complications such as fetal growth restriction and preeclampsia.

According to Jae Jung, PhD, director of the Cleveland Clinic Global Center for Pathogen and Human Health Research, the “findings show that COVID-19 infection during pregnancy leads to distinct immune alterations in mothers and babies, highlighting how important it will be for long-term follow-up after pregnancy to catch and hopefully prevent any unforeseen long-term health conditions related to prenatal infection.”

The investigators also found different immune signatures between pregnant women with asymptomatic and severe COVID-19 infection. The mothers with severe disease had significantly more inflammation and elevated levels of the protein interferon lambda 1 (IFNL1) and its binding receptor, IFNLR1. “This increase in interferon lambda signaling may help explain why we see relatively little direct transmission of COVID-19 between mother and baby during the period right before or after birth — what we call vertical transmission,” said Suan-Sin (Jolin) Foo, PhD, the study’s co-first author.

According to Dr. Foo, “More research will be necessary to determine if increased expression of IFNL1 and IFNLR1 does in fact block vertical transmission.”