Newborn and Early Infant Outcomes Following Maternal COVID-19 Vaccination During Pregnancy

COVID-19 in Pregnancy: An Update for Clinicians

In this review, we will discuss the risks of COVID-19 on maternal, obstetric, and neonatal outcomes. We will also review the safety of COVID-19 vaccination in pregnancy, as well as review the management of COVID-19 in pregnancy.

Newborns at risk of COVID-19, the story continues

After more than 4 years of the SARS-CoV-2 pandemic, a great deal of knowledge on how this virus affects pregnant women, the fetus and the newborn has accumulated. Guidelines for mode of delivery, cord clamping, skin to skin, breastfeeding, and rooming-in have become uniform across the world. Vaccination has considerably improved outcomes, but hesitancy amongst pregnant patients and the emergence of variants remain challenged and SARS-CoV-2 positivity during pregnancy continues to be associated with an increased risk of maternal complications, premature delivery and higher neonatal mortality and morbidity. An emerging body of data now exists on the effect of SARS-CoV-2 in pregnancy on early neonatal outcomes, medical education in obstetrics and pediatrics, and longer-term developmental outcomes. In this article, we review the development in this field since our last review.

Timing of maternal vaccination against COVID-19 for effective protection of neonates: cohort study

Introduction

Although the safety and effectiveness of COVID-19 vaccination during pregnancy have been proven, there is still little data explaining neonatal outcomes of maternal pre-pregnancy vaccination.

Methods

Here, we investigated the impact of vaccination and SARS-CoV-2 infection on maternal-neonate immune response in a cohort study involving 141 pregnant individuals, and defined the importance of maternal COVID-19 vaccination timing for its effectiveness.

Results and discussion

Our data indicate that vertically transferred maternal hybrid immunity provides significantly better antiviral protection for a neonate than either maternal post-infection or post-vaccination immunity alone. Higher neutralization potency among mothers immunized before pregnancy and their newborns highlights the promising role of pre-pregnancy vaccination in neonatal protection. A comparison of neutralizing antibody titers calculated for each dyad suggests that infection and pre-/during-pregnancy vaccination all support transplacental transfer, providing the offspring with strong passive immunity against SARS-CoV-2. Analysis of neutralizing antibody levels in maternal sera collected during pregnancy and later during delivery shows that immunization may exert a positive effect on maternal protection.

COVID-19 Vaccination in the First Trimester and Major Structural Birth Defects Among Live Births

Importance

COVID-19 vaccination is recommended throughout pregnancy to prevent pregnancy complications and adverse birth outcomes associated with COVID-19 disease. To date, data on birth defects after first-trimester vaccination are limited.

Objective

To evaluate the associated risks for selected major structural birth defects among live-born infants after first-trimester receipt of a messenger RNA (mRNA) COVID-19 vaccine.

Design, Setting, and Participants

This was a retrospective cohort study of singleton pregnancies with estimated last menstrual period (LMP) between September 13, 2020, and April 3, 2021, and ending in live birth from March 5, 2021, to January 25, 2022. Included were data from 8 health systems in California, Oregon, Washington, Colorado, Minnesota, and Wisconsin in the Vaccine Safety Datalink.

Exposures

Receipt of 1 or 2 mRNA COVID-19 vaccine doses in the first trimester, as part of the primary series.

Main Outcomes and Measures

Selected major structural birth defects among live-born infants, identified from electronic health data using validated algorithms, with neural tube defects confirmed via medical record review.

Results

Among 42 156 eligible pregnancies (mean [SD] maternal age, 30.9 [5.0] years) 7632 (18.1%) received an mRNA COVID-19 vaccine in the first trimester. Of 34 524 pregnancies without a first-trimester COVID-19 vaccination, 2045 (5.9%) were vaccinated before pregnancy, 13 494 (39.1%) during the second or third trimester, and 18 985 (55.0%) were unvaccinated before or during pregnancy. Compared with pregnant people unvaccinated in the first trimester, those vaccinated in the first trimester were older (mean [SD] age, 32.3 [4.5] years vs 30.6 [5.1] years) and differed by LMP date. After applying stabilized inverse probability weighting, differences in baseline characteristics between vaccinated and unvaccinated pregnant persons in the first trimester were negligible (standardized mean difference <0.20). Selected major structural birth defects occurred in 113 infants (1.48%) after first-trimester mRNA COVID-19 vaccination and in 488 infants (1.41%) without first-trimester vaccine exposure; the adjusted prevalence ratio was 1.02 (95% CI, 0.78-1.33). In secondary analyses, with major structural birth defect outcomes grouped by organ system, no significant differences between infants vaccinated or unvaccinated in the first trimester were identified.

Conclusions and Relevance

In this multisite cohort study, among live-born infants, first-trimester mRNA COVID-19 vaccine exposure was not associated with an increased risk for selected major structural birth defects.

Neonatal and infant infection with SARS-CoV-2

Despite the substantial body of investigative work describing the Coronavirus Disease 2019 (COVID-19) pandemic, its impact on neonates and infants remains less well characterized. Here, we review the data on epidemiology of COVID-19 in this population. Widespread use of universal testing for SARS-CoV-2 among pregnant persons presenting for delivery complicates interpretation of the risks of perinatal exposure. While many neonates and infants with COVID-19 are well-appearing or have only mild signs of illness, factors such as preterm birth, low birth weight, and medical comorbidities increase the risk of severe infection. We highlight potential protective maternal factors, summarize treatment options and discuss vaccine development. Higher quality data are needed to better inform our understanding of COVID-19 in neonates and infants.

High Transferability of Neutralizing Antibodies against SARS-CoV-2 to Umbilical Cord Blood in Pregnant Women Vaccinated with BNT162b2 XBB.1.5: A Retrospective Cohort Study

BACKGROUND

Coronavirus disease 2019 (COVID-19) can lead to severe respiratory illness, rapid disease progression, and higher rates of intensive care unit admission in pregnant women. Infection during pregnancy is associated with an increased risk of preterm delivery, cesarean section, fetal dysfunction, preeclampsia, and perinatal death. Vertical transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from pregnant women to their fetuses has also been observed. Although severe infections in neonates and infants are rare, newborns can experience serious consequences from COVID-19 due to their suboptimal humoral immune system protection. The amino acids in the structural proteins of SARS-CoV-2 are constantly mutating. Since around January 2023, COVID-19, caused by omicron-type SARS-CoV-2 variants, has been prevalent globally. These variants can evade the immune response triggered by traditional mRNA-based COVID-19 vaccines, such as BNT162b2. Therefore, vaccination with BNT162b2 XBB.1.5, which provides protection against omicron-type SARS-CoV-2 variants, is recommended.

METHODS

This retrospective cohort study included 148 pregnant women who received the BNT162b2 XBB.1.5 vaccine at 30 partner medical institutions from September 2023 to January 2024. We examined the titers of anti-spike glycoprotein SARS-CoV-2 immunoglobin G (IgG) and IgA in the blood and umbilical cord blood obtained from the participants using ELISA.

FINDINGS

Anti-spike glycoprotein SARS-CoV-2 IgG and IgA titers were highest in the blood and cord blood at late gestational age (28-34 weeks). No serious side effects or adverse events were observed in either the pregnant women or their newborns.

INTERPRETATION

Pregnant women who received the BNT162b2 XBB.1.5 vaccine during gestational weeks 28 to 34 had the highest titers of anti-omicron SARS-CoV-2 variant antibodies in their blood. Moreover, these antibodies were transferred to their umbilical cord blood. To validate our findings, large cohort clinical studies involving numerous pregnant women are warranted.

FUNDING

This study was funded by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS) and Grants-in-Aid for Medical Research from the Japan Agency for Medical Research and Development (AMED).

Perinatal outcomes after admission with COVID-19 in pregnancy: a UK national cohort study

There are few population-based studies of sufficient size and follow-up duration to have reliably assessed perinatal outcomes for pregnant women hospitalised with SARS-CoV-2 infection. The United Kingdom Obstetric Surveillance System (UKOSS) covers all 194 consultant-led UK maternity units and included all pregnant women admitted to hospital with an ongoing SARS-CoV-2 infection. Here we show that in this large national cohort comprising two years' active surveillance over four SARS-CoV-2 variant periods and with near complete follow-up of pregnancy outcomes for 16,627 included women, severe perinatal outcomes were more common in women with moderate to severe COVID-19, during the delta dominant period and among unvaccinated women. We provide strong evidence to recommend continuous surveillance of pregnancy outcomes in future pandemics and to continue to recommend SARS-CoV-2 vaccination in pregnancy to protect both mothers and babies.

Social Media Misinformation about Pregnancy and COVID-19 Vaccines: A Systematic Review

OBJECTIVE

The objectives of this study were to identify common social media misconceptions about COVID-19 vaccination in pregnancy, explain the spread of misinformation, and identify solutions to guide clinical practice and policy.

METHODOLOGY

A systematic review was conducted and the databases Embase and Medline were searched from December 2019 to February 8, 2023, using terms related to social media, pregnancy, COVID-19 vaccines and misinformation. The inclusion criteria were original research studies that discussed misinformation about COVID-19 vaccination during pregnancy on social media. The exclusion criteria were review articles, no full text, and not published in English. Two independent reviewers conducted screening, extraction, and quality assessment.

RESULTS

Our search identified 76 articles, of which 3 fulfilled eligibility criteria. Included studies were of moderate and high quality. The social media platforms investigated included Facebook, Google Searches, Instagram, Reddit, TikTok, and Twitter. Misinformation was related to concerns regarding vaccine safety, and its association with infertility. Misinformation was increased due to lack of content monitoring on social media, exclusion of pregnant women from early vaccine trials, lack of information from reputable health sources on social media, and others. Suggested solutions were directed at pregnancy care providers (PCPs) and public health/government. Suggestions included: (i) integrating COVID-19 vaccination information into antenatal care, (ii) PCPs and public health should increase their social media presence to disseminate information, (iii) address population-specific vaccine concerns in a culturally relevant manner, and others.

CONCLUSION

Increased availability of information from reputable health sources through multiple channels could increase COVID-19 vaccine uptake in the pregnant population and help combat misinformation.

Pregnancy Outcomes among Pregnant Persons after COVID-19 Vaccination: Assessing Vaccine Safety in Retrospective Cohort Analysis of U.S. National COVID Cohort Collaborative (N3C)

COVID-19 vaccines have been shown to be effective in preventing severe illness, including among pregnant persons. The vaccines appear to be safe in pregnancy, supporting a continuously favorable overall risk/benefit profile, though supportive data for the U.S. over different periods of variant predominance are lacking. We sought to analyze the association of adverse pregnancy outcomes with COVID-19 vaccinations in the pre-Delta, Delta, and Omicron SARS-CoV-2 variants' dominant periods (constituting 50% or more of each pregnancy) for pregnant persons in a large, nationally sampled electronic health record repository in the U.S. Our overall analysis included 311,057 pregnant persons from December 2020 to October 2023 at a time when there were approximately 3.6 million births per year. We compared rates of preterm births and stillbirths among pregnant persons who were vaccinated before or during pregnancy to persons vaccinated after pregnancy or those who were not vaccinated. We performed a multivariable Poisson regression with generalized estimated equations to address data site heterogeneity for preterm births and unadjusted exact models for stillbirths, stratified by the dominant variant period. We found lower rates of preterm birth in the majority of modeled periods (adjusted incidence rate ratio [aIRR] range: 0.42 to 0.85; p-value range: <0.001 to 0.06) and lower rates of stillbirth (IRR range: 0.53 to 1.82; p-value range: <0.001 to 0.976) in most periods among those who were vaccinated before or during pregnancy compared to those who were vaccinated after pregnancy or not vaccinated. We largely found no adverse associations between COVID-19 vaccination and preterm birth or stillbirth; these findings reinforce the safety of COVID-19 vaccination during pregnancy and bolster confidence for pregnant persons, providers, and policymakers in the importance of COVID-19 vaccination for this group despite the end of the public health emergency.

Neonatal Outcomes After COVID-19 Vaccination in Pregnancy

Importance

Better knowledge about neonatal adverse events after COVID-19 vaccination during pregnancy could help address concerns about vaccine safety.

Objective

To evaluate the risks of neonatal adverse events after exposure to COVID-19 vaccination during pregnancy.

Design, Setting, and Participants

Population-based cohort study including all infants in Sweden and Norway born from June 2021 to January 2023. Unique personal identity numbers were used to link individual information from different national registers.

Exposure

Administration of any mRNA vaccine against COVID-19 during pregnancy, irrespective of previous vaccination, number of doses during pregnancy, or vaccine manufacturer.

Main Outcomes and Measures

Outcomes were neonatal conditions with bleeding/thrombosis or inflammation/infection; disorders of the central nervous system; circulatory, respiratory, or gastrointestinal problems; and neonatal mortality. Statistical methods included logistic regression adjusted for characteristics of the pregnant individuals, with additional restricted and stratified analyses.

Results

Of 196 470 newborn infants included (51.3% male, 93.8% born at term, 62.5% born in Sweden), 94 303 (48.0%) were exposed to COVID-19 vaccination during pregnancy. Exposed infants exhibited no increased odds of adverse neonatal outcomes, and they exhibited lower odds for neonatal nontraumatic intracranial hemorrhage (event rate, 1.7 vs 3.2/1000; adjusted odds ratio [aOR], 0.78 [95% CI, 0.61-0.99]), hypoxic-ischemic encephalopathy (1.8 vs 2.7/1000; aOR, 0.73 [95% CI, 0.55-0.96]), and neonatal mortality (0.9 vs 1.8/1000; aOR, 0.68 [95% CI, 0.50-0.91]). Subgroup analyses found a similar association between vaccination during pregnancy and lower neonatal mortality; subgroups were restricted to infants delivered by individuals unvaccinated before pregnancy, individuals vaccinated before pregnancy, individuals vaccinated after a general recommendation of vaccination during pregnancy was issued, and individuals without COVID-19 infection during pregnancy. Analyses restricted to term infants, singleton births, or infants without birth defects yielded similar results. Stratifying the analysis by vaccine manufacturer did not attenuate the association between vaccination and low neonatal mortality.

Conclusions and Relevance

In this large population-based study, vaccination of pregnant individuals with mRNA COVID-19 vaccines was not associated with increased risks of neonatal adverse events in their infants.