COVID-19 vaccine during pregnancy provides mother-infant immunity


In a recent study, higher immunoglobulin G titers were seen in infants of mothers who received messenger RNA COVID-19 vaccination during pregnancy.

COVID-19 vaccine during pregnancy provides mother-infant immunity | Image Credit: © Leigh Prather - © Leigh Prather -

COVID-19 vaccine during pregnancy provides mother-infant immunity | Image Credit: © Leigh Prather - © Leigh Prather -

According to a recent study published in JAMA Network Open, messenger RNA (mRNA) COVID-19 vaccination during pregnancy provides an immunoglobulin G (IgG) response for the mother-infant dyad for about 6 months after birth.

COVID-19 infection during pregnancy has been linked to increased risks of severe illness, mortality, and pregnancy-related complications. As data has indicated safety and efficacy when using the mRNA COVID-19 vaccine during pregnancy, public health officials have recommended vaccination before, during, and after pregnancy.

Despite current recommendations, there are gaps in knowledge about the reactogenicity and immunogenicity in mother-infant dyads from COVID-19 mRNA vaccinations. This may lead pregnant individuals to worry about potential adverse events from vaccination for themselves and their fetuses.

To determine the association between COVID-19 mRNA vaccination reactogenicity and immunogenicity during pregnancy and mother-infant dyad outcomes, investigators conducted a prospective cohort study. The cohort was comprised of pregnant individuals from the COVID-19 Vaccine in Pregnancy and Lactation study.

Participants were recruited at a large academic medical center by self-referral and prenatal clinics. Eligibility criteria included planning to receive a COVID-19 mRNA vaccine during pregnancy and being willing to provide blood samples.

Participants were enrolled between December 1, 2020, and December 31, 2021, and maternal-infant outcomes were assessed through March 31, 2022. Individuals who did not receive a second mRNA dose at least 2 weeks before delivery were excluded from the analysis.

Information gathered from medical records included vaccine manufacturer, maternal age at vaccination, parity, gravidity, gestational age at first mRNA dose, prepregnancy body mass index, race and ethnicity, COVID-19 diagnosis, pregnancy complications, mode of delivery, gestational age at delivery, and infant Apgar scores, birth weight, and hospitalization data.

Online surveys on adverse effects of COVID-19 vaccination were sent to participants, with follow-up surveys used to collect data on booster doses and breakthrough infection. Maternal blood samples were collected before vaccination, after first dose, after second dose, and after third dose.

At delivery, maternal blood and cord blood samples were collected. Infant blood samples were collected at 6 to 8 weeks, 3 to 4 months, 5 to 6 months, and 9 to 12 months after delivery.

There were 76 participants included in the final analysis, with a median maternal age of 35 years. Of participants, 55.3% received the BNT162b2 vaccine, 44.7% received the mRNA-1237 vaccine, 36.8% were primigravid, and 48.7% were nulliparous. The first vaccine dose was received at a median 22.8 weeks’ gestational age, and the third dose was mostly received postpartum.

Information on postvaccination symptoms was gathered through a survey, which was completed by 78.9% of participants for dose 1, 76.3% for dose 2, and 32.9% for dose 3. Symptoms commonly reported included injection-site tenderness, erythema, chills, fever, nausea or vomiting, headaches, and muscle or body aches.

A strong antibody response was seen after vaccination for all trimesters of pregnancy, with the response lasting through delivery. When evaluating IgG titers between individuals who received a first trimester and second trimester vaccination, no differences were observed. However, a higher IgG titer was seen among individuals vaccinated in the third trimester.

Transplacental IgG transfer at delivery was also seen in all trimester groups, with no differences in maternal and cord blood IgG titers at delivery between first and third trimester groups. Higher median cord blood IgG titers were seen in the second trimester group.

The presence of local injection-site symptoms following vaccination was not associated with changes in median IgG titers. However, 65.6% higher median IgG titers were seen in patients with systemic postvaccination symptoms.

Most perinatal outcomes did not differ in patients with mRNA vaccination, but preterm delivery was only seen among mRNA-1237 recipients, accounting for 5.3% of the total cohort. In infants, positive IgG titers were seen for at least 5 to 6 months after delivery. Infants also had slower 30-day rates of antibody decline than their mothers.

These results indicated strong immune responses for mother-infant dyads when mRNA COVID-19 vaccination is received during pregnancy. Investigators recommended further studies on this association be conducted.


Cassidy AG, Li L, Golan Y, et al. Assessment of adverse reactions, antibody patterns, and 12-month outcomes in the mother-infant dyad after COVID-19 mRNA vaccination in pregnancy. JAMA Netw Open. 2023;6(7):e2323405. doi:10.1001/jamanetworkopen.2023.23405

This article was initially published by our sister publication, Contemporary OB/GYN®.

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