Immune Changes in Mothers, Infants Linked to COVID-19 Infection

Perhaps another reason why pregnant women should get the COVID-19 vaccine? Investigators found COVID-19 infection altered the mothers’ immunity at delivery, and gestational COVID-19 exposure alters the immunity of the newborns.

One of the groups hesitant to get the COVID-19 vaccine is pregnant women. As Infection Control Today® (ICT®) reported last month when the Centers for Disease Control and Prevention (CDC) issued an advisory to health care providers faced with vaccine hesitancy among pregnant women or women who’ve just given birth, misinformation might be fueling that hesitancy. Infection preventionists (IPs) have been urged to fight misinformation about COVID-19 among the public and even their fellow health care professionals. As ICT® reported last month, IPs know the reliable sources and are familiar with reading scientific studies and being able to translate those findings to staff in an understandable way.

One of those reliable sources is the Cleveland Clinic, and investigators at the Clinic sought to understand the clinical and immunological implications of COVID-19 on maternal-to-fetal health.

“We know that pregnancy increases maternal risk for COVID-19, but relatively little is known about the long-term consequences of in utero exposure for infants,” said Jae Jung, PhD, director of the Cleveland Clinic Global Center for Pathogen and Human Health Research.

The study, published in Cell Reports Medicineincluded 93 mothers with COVID-19 and 45 of their infants who were exposed to the virus. The investigators compared maternal blood specimens collected close to the original date of COVID-19 infection and throughout pregnancy and delivery. They studied immune profiles for over 1400 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 was high incidents of certain complications like fetal growth restriction and preeclampsia.

Jung reported, “Our 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 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.

There was no robust data suggesting vertical transmission, but the investigators found COVID-19 infection altered the mothers’ immunity at delivery, and gestational COVID-19 exposure alters the immunity of the newborns.

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

The article originally appeared in Contagion®.