Decreased severity of COVID-19 in vaccinated pregnant individuals during predominance of different SARS-CoV-2 variants

A prospective cohort study of pregnancy outcomes following antepartum infection with SARS-CoV-2

OBJECTIVES

Our study aimed to explore the impact of COVID-19 infection on pregnancy outcomes, accounting for the progression of variants, vaccines, and treatment modalities.

STUDY DESIGN

We performed a prospective longitudinal cohort study at two urban tertiary centers enrolling patients with a confirmed intrauterine singleton pregnancy from December 23, 2020 to July 18, 2022. Patients were evaluated for SARS-CoV-2 infection at enrollment and every trimester using serum antibody testing. The primary outcome was preterm birth. Symptom and treatment data were collected from pregnant patients with COVID-19 infections. Variant strain infection status was determined from local wastewater analysis.

RESULTS

448 patients were enrolled, and 390 patients were retained through delivery with 159 unexposed and 231 exposed patients, of whom 56 patients (26.0 %) crossed over after enrollment to the exposed cohorts during pregnancy. There was no difference in rates of preterm birth between exposed and unexposed cohorts (14.6 % vs 11.3 %), in deliveries < 34 weeks (1.5 % vs 2.7 %), PPROM, (0.4 % vs 1.3 %), or gestational age at delivery (38.1 vs 38.2). Exposed patients were significantly more likely to be diagnosed with a hypertensive disorder (aOR 2.3, 95 % CI 1.2-4.1), specifically gestational hypertension (aOR 2.8, 95 % CI 1.3--6.0), but not preeclampsia/eclampsia. There were no differences in individual or composite neonatal outcomes.

CONCLUSIONS

Our study contributed to the understanding of the effects of SARS-CoV-2 infection on pregnancy outcomes, with increased risk of hypertensive disorders of pregnancy but overall, no differences in adverse neonatal outcomes. Regular antenatal PCR and antibody screening allowed for higher detection and inclusion of patients with asymptomatic SARS-CoV-2 infection and effects on maternal and neonatal outcomes.

An Update on COVID-19 Vaccination and Pregnancy

Pregnant women are more prone to experience severe COVID-19 disease, including intensive care unit (ICU) admission, use of invasive ventilation, extracorporeal membrane oxygenation (ECMO), and mortality compared to non-pregnant individuals. Additionally, research suggests that SARS-CoV-2 infection during pregnancy is linked to adverse pregnancy outcomes, such as preterm birth, preeclampsia, and stillbirth, as well as adverse neonatal outcomes, including hospitalization and admission to the neonatal intensive care unit. This review assessed the available literature from November 2021 to 19 March 2023, concerning the safety and effectiveness of COVID-19 vaccination during pregnancy. COVID-19 vaccination administered during pregnancy is not linked to significant adverse events related to the vaccine or negative obstetric, fetal, or neonatal outcomes. Moreover, the vaccine has the same effectiveness in preventing severe COVID-19 disease in pregnant individuals as in the general population. Additionally, COVID-19 vaccination is the safest and most effective method for pregnant women to protect themselves and their newborns from severe COVID-19 disease, hospitalization, and ICU admission. Thus, vaccination should be recommended for pregnant patients. While the immunogenicity of vaccination in pregnancy appears to be similar to that in the general population, more research is needed to determine the optimal timing of vaccination during pregnancy for the benefit of the neonate.

Vaccination options for pregnant women during the Omicron period

Omicron exhibits reduced pathogenicity in general population than the previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants. However, the severity of disease and pregnancy outcomes of Omicron infection among pregnant women have not yet been definitively established. Meanwhile, substantial proportions of this population have doubts about the necessity of vaccination given the reports of declining efficacy of coronavirus disease 2019 (COVID-19) vaccines. Herein, we comprehensively discuss the clinical outcomes of infected pregnant women during the Omicron period and summarize the available data on the safety and efficacy profile of COVID-19 vaccination. The results found that the incidence of moderate and severe disease, maternal mortality, pregnancy loss, preterm delivery, stillbirth, preeclampsia/eclampsia, and gestational hypertension during the Omicron period are similar to those during the Pre-Delta period. In view of the effects of mass vaccination and previous natural infection on disease severity, the virulence of Omicron in pregnant women may be comparable to or even higher than that of the Pre-Delta variant. Moreover, the currently approved COVID-19 vaccines are safe and effective for pregnant women. Particularly, those who received a second or third dose had significantly less severe disease with little progression to critical illness or death compared with those who were unvaccinated or received only one dose. Therefore, in the case of the rapid spread of Omicron, pregnant women should still strictly follow preventive measures to avoid infection and receive the COVID-19 vaccine in a timely manner.

Comparison of Maternal-Fetal Outcomes among Unvaccinated and Vaccinated Pregnant Women with COVID-19

Background: This study sought to elucidate whether COVID-19 vaccination, during gestation or before conception, entails a decreased incidence of severe COVID-19 disease during pregnancy. Methods: This retrospective cohort study included all pregnant women that were followed up at a tertiary University Hospital with SARS-CoV-2 infection diagnosed between 1 March 2020 and 30 July 2022. The primary outcome of the study was to compare maternal and perinatal outcomes in unvaccinated and vaccinated pregnant patients with SARS-CoV-2 infection. Results: A total of 487 pregnant women with SARS-CoV-2 infection were included. SARS-CoV-2 infection during the third trimester of pregnancy was associated with an 89% lower probability of positive cord-blood SARS-CoV-2 IgG antibodies (OR 0.112; 95% CI 0.039-0.316), compared with infection during the first or the second trimester. Vaccinated pregnant women (201 (41.27%)) with COVID-19 had an 80% lower risk for developing pneumonia and requiring hospital admission due to COVID-19 than unvaccinated patients (aOR 0.209; 95% CI 0.044-0.985). Noticeably, pregnant patients with SARS-CoV-2 infection with at least two doses of the COVID-19 vaccine did not develop severe COVID-19. Conclusion: Vaccinated women with SARS-CoV-2 infection during pregnancy are associated with decreased hospital admission due to COVID-19 as well as reduced progression to severe COVID-19.

The impact of maternal SARS-CoV-2 infection and COVID-19 vaccination on maternal-fetal outcomes

The rapidly evolving COVID-19 pandemic has resulted in an upsurge of scientific productivity to help address the global health crisis. One area of active research is the impact of COVID-19 on pregnancy. Here, we provide an epidemiological overview about what is known about the effects of maternal SARS-CoV-2 infection and COVID-19 vaccination on maternal-fetal outcomes, and identify gaps in knowledge. Pregnant people are at increased risk for severe COVID-19, and maternal SARS-CoV-2 infection increases the risk of negative maternal-fetal outcomes. Despite this elevated risk, there have been high rates of vaccine hesitancy, heightened by the initial lack of safety and efficacy data for COVID-19 vaccination in pregnancy. In response, retrospective cohort studies were performed to examine the impact of COVID-19 vaccination during pregnancy. Here, we report the vaccine's efficacy during pregnancy and its impact on maternal-fetal outcomes, as well as an overview of initial studies on booster shots in pregnancy. We found that pregnant people are at risk for more severe COVID-19 outcomes, maternal SARS-CoV-2 infection is associated with worse birth outcomes, COVID-19 vaccine hesitancy remains prevalent in the pregnant population, and COVID-19 vaccination and boosters promote better maternal-fetal outcomes. The results should help reduce vaccine hesitancy by alleviating concerns about the safety and efficacy of administering the COVID-19 vaccine during pregnancy. Overall, this review provides an introduction to COVID-19 during pregnancy. It is expected to help consolidate current knowledge, accelerate research of COVID-19 during pregnancy and inform clinical, policy, and research decisions regarding COVID-19 vaccination in pregnant people.

Association of Infection with Different SARS-CoV-2 Variants during Pregnancy with Maternal and Perinatal Outcomes: A Systematic Review and Meta-Analysis

The aim of this study is to review the currently available data, and to explore the association of infection with different severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants during pregnancy with maternal and perinatal outcomes in the real world. Observational cohort studies were analyzed that described the maternal and perinatal outcomes of infection with different SARS-CoV-2 variants during pregnancy. Random-effects inverse-variance models were used to evaluate the pooled prevalence (PP) and its 95% confidence interval (CI) for maternal and perinatal outcomes. Random effects were used to estimate the pooled odds ratios (OR) and their 95% CI for different outcomes between Delta and pre-Delta periods, and between Omicron and Delta periods. Eighteen studies, involving a total of 133,058 cases of SARS-CoV-2 infection during pregnancy (99,567 cases of SARS-CoV-2 wild type or pre-variant infection and 33,494 cases of SARS-CoV-2 variant infections), were included in this meta-analysis. Among pregnant women with SARS-CoV-2 infections, the PPs for required respiratory support, severe or critical illness, intensive care unit (ICU) admission, maternal death, and preterm birth <37 weeks were, respectively, 27.24% (95%CI, 20.51−33.97%), 24.96% (95%CI, 15.96−33.96%), 11.31% (95%CI, 4.00−18.61%), 4.20% (95%CI, 1.43−6.97%), and 33.85% (95%CI, 21.54−46.17%) in the Delta period, which were higher than those in the pre-Delta period, while the corresponding PPs were, respectively, 10.74% (95%CI, 6.05−15.46%), 11.99% (95%CI, 6.23−17.74%), 4.17% (95%CI, 1.53−6.80%), 0.63% (95%CI, 0.05−1.20%), and 18.58% (95%CI, 9.52−27.65%). The PPs for required respiratory support, severe or critical illness, and ICU admission were, respectively, 2.63% (95%CI, 0.98−4.28%), 1.11% (95%CI, 0.29−1.94%), and 1.83% (95%CI, 0.85−2.81%) in the Omicron period, which were lower than those in the pre-Delta and Delta periods. These results suggest that Omicron infections are associated with less severe maternal and neonatal adverse outcomes, though maternal ICU admission, the need for respiratory support, and preterm birth did also occur with Omicron infections. Since Omicron is currently the predominant strain globally, and has the highest rates of transmission, it is still important to remain vigilant in protecting the vulnerable populations of mothers and infants. In particular, obstetricians and gynecologists should not ignore the adverse risks of maternal ICU admission, respiratory support, and preterm births in pregnant patients with SARS-CoV-2 infections, in order to protect the health of mothers and infants.