A population-based matched cohort study of early pregnancy outcomes following COVID-19 vaccination and SARS-CoV-2 infection

Coronavirus Disease 2019 (COVID-19) Vaccination and Spontaneous Abortion

OBJECTIVE

To examine the association between coronavirus disease 2019 (COVID-19) vaccination and spontaneous abortion.

METHODS

We conducted a case-control study of clinically adjudicated spontaneous abortions (case group) occurring between January 19, 2021, and October 27, 2021, and live births (control group). Patients aged 16-49 years at eight Vaccine Safety Datalink sites who had singleton pregnancies, one or more prenatal visits, continuous health plan enrollment, and spontaneous abortion (fetal loss between 6 and less than 20 weeks of gestation) or live birth were eligible. A random sample of eligible patients with spontaneous abortions was adjudicated to confirm pregnancy outcome, outcome date, and gestational age at fetal death; patients in the adjudicated spontaneous abortion case group were matched 1:2 on Vaccine Safety Datalink site, maternal age, and pregnancy start date with eligible patients with live births. Vaccine exposure was considered from pregnancy start to spontaneous abortion date or equivalent gestational age for the matched live births (index date). Conditional logistic regression was used to evaluate the association between COVID-19 vaccination in pregnancy and spontaneous abortion; secondary analyses explored associations by dose number, vaccine manufacturer, and vaccination within 6 weeks of the spontaneous abortion.

RESULTS

Matched analyses included 296 patients in the spontaneous abortion case group and 592 in the live birth control group. There was no association between spontaneous abortion and COVID-19 vaccination (adjusted odds ratio [aOR] 0.85, 95% CI, 0.56-1.30). There was also no association between spontaneous abortion and dose number compared with no vaccine (one dose: aOR 0.81, 95% CI, 0.39-1.70; two doses: aOR 0.84, 95% CI, 0.51-1.38; vaccine manufacturer: Moderna aOR 0.59, 95% CI, 0.29-1.19 and Pfizer-BioNTech aOR 0.97, 95% CI, 0.57-1.66; or vaccine exposure window of 6 weeks before spontaneous abortion or index date: aOR 0.87, 95% CI, 0.53-1.44).

CONCLUSION

There was no observed association between COVID-19 vaccination in pregnancy and spontaneous abortion. Findings support the safety of COVID-19 vaccination in early pregnancy.

Maternal Vaccination and Protective Immunity Against SARS-CoV-2 Infection in Pups

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has had a devastating impact worldwide. Currently, several vaccines are approved for emergency use in humans, and these vaccines have played a large role in controlling COVID-19. Pregnant women and newborns constitute a special population for vaccine policy. Here, we established a maternal vaccination model by injecting pregnant mice with a SARS-CoV-2 receptor-binding domain (RBD) homodimer. Maternal immunization with the RBD dimer did not cause obvious adverse effects on pregnancy or fetal development. Moreover, two-shot immunization fully protected dams and fetuses from SARS-CoV-2 infection during pregnancy. Neutralizing antibodies can be transferred from immunized dams to pups, providing protection for both lactating and weaned pups against SARS-CoV-2 infection. Our results indicate that, in addition to being used to vaccinate nonpregnant individuals, the RBD dimer can also be considered for maternal vaccination.

Pregnancy loss <28 weeks gestation in maternal influenza and COVID-19 vaccination studies: a review of data sources, 2009-2024

OBJECTIVES

To address gaps in maternal vaccination and pregnancy loss research, large, complex datasets are needed. We aimed to identify and evaluate data sources and data collection methods currently used to capture pregnancy losses <28 weeks following maternal influenza and COVID-19 vaccination research.

STUDY DESIGN

Narrative Review.

METHODS

PubMed, CINAHL, Scopus, and Web of Science were used to identify studies that investigated pregnancy loss <28 gestational weeks following influenza and COVID-19 vaccinations from January 1st, 2009, to March 19th, 2024. Within the resulting studies, the data source(s) used to capture exposure and outcome data were identified and categorised. The capacity to capture and measure exposures, outcomes, and missing data within categories was investigated.

RESULTS

28 articles met the inclusion criteria, representing 1,113,878 participants. Most articles (n = 19) used multiple data sources within the one study, often obtaining exposure and outcome data from separate data sources. Categories of data sources included: registries, adverse reporting systems, medical records, and survey or interview methods.

CONCLUSION

Current data collection practices and existing data sources are adversely impacting data quality, and the ability to combine large datasets necessary for analysing early pregnancy loss risk factors. This also hinders our ability to evaluate the safety of early maternal vaccination and subsequent miscarriage. Establishing pregnancy loss registries using standardised data collection and coding practices, consistent terminology, and accurate exposure and outcome timing is critical. In the absence of registries, we propose an alternative source to capture both pregnancy loss and maternal vaccination data.

COVID-19 Vaccine Safety in Pregnancy, A Nested Case-Control Study in Births From April 2021 to March 2022, England

OBJECTIVE

Assessment of COVID-19 vaccine safety in pregnancy using population-based data.

DESIGN

Matched case-control study nested in a retrospective cohort.

SETTING

April 2021-March 2022, England.

POPULATION OR SAMPLE

All pregnant individuals aged between 18 and 50 years with valid health records.

METHODS

Individuals identified from the national Maternity Services Data Set (MSDS) had their records linked to hospital admission, national COVID-19 vaccine and COVID-19 testing databases. Matching included participant's age and estimated week of conception. We compared outcomes across multiple COVID-19 vaccine exposures using conditional multivariable logistic regression, adjusting for demographic and health characteristics.

MAIN OUTCOME MEASURES

Adverse pregnancy, maternal and neonatal outcomes.

RESULTS

514 013 individuals were included. We found lower odds of giving birth to a baby who was low birthweight (aOR = 0.86, 95% CI: 0.79-0.93), preterm (aOR = 0.89, 95% CI: 0.85-0.92) or who had an Apgar score < 7 at 5 min of age (aOR = 0.89, 95% CI: 0.80-0.98) for individuals who received at least one dose of COVID-19 vaccine during pregnancy. The odds of admission to intensive care unit during pregnancy were lower in those vaccinated (aOR = 0.85, 95% CI: 0.76-0.95). There was no association between vaccination in pregnancy and stillbirth, neonatal death, perinatal death and maternal venous thromboembolism in pregnancy.

CONCLUSIONS

COVID-19 vaccines are safe to use in pregnancy. Our findings generated important information to communicate to pregnant individuals and health professionals to support COVID-19 maternal vaccination programmes.

COVID-19 infection during pregnancy and risk of early and late spontaneous miscarriages: A matched case-control population-based study

OBJECTIVES

To evaluate the effect of COVID-19 during the first trimester on the rate of first- and second-trimester miscarriages. Secondary aims include the effect on stillbirths and the correlation between symptom severity and pregnancy outcomes.

METHODS

A retrospective matched case-control population-based study extracted data from electronic medical records of a nationwide database of the second largest healthcare organization that provides medical services to over 2 000 000 patients in Israel. Pregnancy outcomes in COVID-19-positive pregnant patients in 2020 were compared with an age- and gestational-week-matched 1:2 case-control cohort of pre-pandemic pregnant patients that received medical care in 2019.

RESULTS

Of 68 485 pregnant women treated in 2020, 2333 were COVID-19-positive during pregnancy: 215 during the first trimester, 791 during the second trimester, and 1327 during the third trimester. We compared these data with the control cohort of 4580 pre-pandemic pregnant patients. The rate of spontaneous miscarriage was significantly higher 146/2187 (6.3%) in COVID-19-positive patients versus 214/4580 (4.7%), (P < 0.01, odds ratio 1.34, 95% confidence interval 1.094-1.691). Most miscarriages occurred during the first trimester in both groups, yet the rates were significantly higher in the study group (5.4% vs 3.8%, P < 0.01). There was no association between COVID-19 severity and miscarriage risk.

CONCLUSION

COVID-19 diagnosis during early pregnancy increased the rate of spontaneous miscarriage in our cohort compared with an age- and gestational-week-matched pre-pandemic control group.

COVID-19 diagnosis, vaccination during pregnancy, and adverse pregnancy outcomes of 865,654 women in England and Wales: a population-based cohort study

Background

The extent to which COVID-19 diagnosis and vaccination during pregnancy are associated with risks of common and rare adverse pregnancy outcomes remains uncertain. We compared the incidence of adverse pregnancy outcomes in women with and without COVID-19 diagnosis and vaccination during pregnancy.

Methods

We studied population-scale linked electronic health records for women with singleton pregnancies in England and Wales from 1 August 2019 to 31 December 2021. This time period was divided at 8th December 2020 into pre-vaccination and vaccination roll-out eras. We calculated adjusted hazard ratios (HRs) for common and rare pregnancy outcomes according to the time since COVID-19 diagnosis and vaccination and by pregnancy trimester and COVID-19 variant.

Findings

Amongst 865,654 pregnant women, we recorded 60,134 (7%) COVID-19 diagnoses and 182,120 (21%) adverse pregnancy outcomes. COVID-19 diagnosis was associated with a higher risk of gestational diabetes (adjusted HR 1.22, 95% CI 1.18-1.26), gestational hypertension (1.16, 1.10-1.22), pre-eclampsia (1.20, 1.12-1.28), preterm birth (1.63, 1.57-1.69, and 1.68, 1.61-1.75 for spontaneous preterm), very preterm birth (2.04, 1.86-2.23), small for gestational age (1.12, 1.07-1.18), thrombotic venous events (1.85, 1.56-2.20) and stillbirth (only within 14-days since COVID-19 diagnosis, 3.39, 2.23-5.15). HRs were more pronounced in the pre-vaccination era, within 14-days since COVID-19 diagnosis, when COVID-19 diagnosis occurred in the 3rd trimester, and in the original variant era. There was no evidence to suggest COVID-19 vaccination during pregnancy was associated with a higher risk of adverse pregnancy outcomes. Instead, dose 1 of COVID-19 vaccine was associated with lower risks of preterm birth (0.90, 0.86-0.95), very preterm birth (0.84, 0.76-0.94), small for gestational age (0.93, 0.88-0.99), and stillbirth (0.67, 0.49-0.92).

Interpretation

Pregnant women with a COVID-19 diagnosis have higher risks of adverse pregnancy outcomes. These findings support recommendations towards high-priority vaccination against COVID-19 in pregnant women.

Funding

BHF, ESRC, Forte, HDR-UK, MRC, NIHR and VR.

Safety of COVID-19 Vaccination in Pregnancy: A Systematic Review

The COVID-19 pandemic has posed significant risks to pregnant women and those recently pregnant, leading to heightened mortality and morbidity rates. Vaccination has emerged as a pivotal strategy in reducing COVID-19-related deaths and illnesses worldwide. However, the initial exclusion of pregnant individuals from most clinical trials raised concerns about vaccine safety in this population, contributing to vaccine hesitancy. This review aims to consolidate the existing literature to assess the safety and efficacy of COVID-19 vaccination in pregnant populations and neonatal outcomes. Diverse studies were included evaluating various aspects of safety for women and their newborns, encompassing mild to severe symptoms across different vaccines. The findings indicate the overall safety and efficacy of COVID-19 vaccination, with minimal adverse outcomes observed, including mild side effects like pain and fever. Although most studies reported the absence of severe adverse outcomes, isolated case reports have raised concerns about potential associations between maternal COVID-19 vaccination and conditions such as fetal supraventricular tachycardia and immune-mediated diseases. Our review underscores the importance of ongoing surveillance and monitoring to ensure vaccine safety in pregnant women. Overall, COVID-19 vaccination during pregnancy remains a safe and effective strategy, emphasizing the need for continued research and vigilance to safeguard maternal and fetal health.

Coronavirus Disease 2019 (COVID-19) Vaccination and Stillbirth in the Vaccine Safety Datalink

OBJECTIVE

Coronavirus disease 2019 (COVID-19) vaccination is recommended in pregnancy to reduce the risk of severe morbidity from COVID-19. However, vaccine hesitancy persists among pregnant people, with risk of stillbirth being a primary concern. Our objective was to examine the association between COVID-19 vaccination and stillbirth.

METHODS

We performed a matched case-control study in the Vaccine Safety Datalink (VSD). Stillbirths and live births were selected from singleton pregnancies among persons aged 16-49 years with at least one prenatal, delivery, or postpartum visit at eight participating VSD sites. Stillbirths identified through diagnostic codes were adjudicated to confirm the outcome, date, and gestational age at fetal death. Confirmed antepartum stillbirths that occurred between February 14, 2021, and February 27, 2022, then were matched 1:3 to live births by pregnancy start date, VSD site, and maternal age at delivery. Associations among antepartum stillbirth and COVID-19 vaccination in pregnancy, vaccine manufacturer, number of vaccine doses received, and vaccination within 6 weeks before stillbirth (or index date in live births) were evaluated using conditional logistic regression.

RESULTS

In the matched analysis of 276 confirmed antepartum stillbirths and 822 live births, we found no association between COVID-19 vaccination during pregnancy and stillbirth (38.4% stillbirths vs 39.3% live births in vaccinated individuals, adjusted odds ratio [aOR] 1.02, 95% CI, 0.76-1.37). Furthermore, no association between COVID-19 vaccination and stillbirth was detected by vaccine manufacturer (Moderna: aOR 1.00, 95% CI, 0.62-1.62; Pfizer-BioNTech: aOR 1.00, 95% CI, 0.69-1.43), number of vaccine doses received during pregnancy (1 vs 0: aOR 1.17, 95% CI, 0.75-1.83; 2 vs 0: aOR 0.98, 95% CI, 0.81-1.17), or COVID-19 vaccination within the 6 weeks before stillbirth or index date compared with no vaccination (aOR 1.16, 95% CI, 0.74-1.83).

CONCLUSION

No association was found between COVID-19 vaccination and stillbirth. These findings further support recommendations for COVID-19 vaccination in pregnancy.

COVID-19 vaccination during pregnancy and adverse perinatal outcomes: a systematic review and meta-analysis

We aimed to estimate the associations between coronavirus disease 2019 (COVID-19) vaccination during pregnancy and the risks of adverse perinatal outcomes. We performed a literature search in PubMed, Web of Science and Embase to identify eligible studies published up to 24 September 2023, yielding 39 included studies. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated with a random effects model. The pooled results showed that COVID-19 vaccination during pregnancy (any type or dose of COVID-19 vaccination during any trimester) was not associated with an increased risk of adverse perinatal outcomes. In particular, COVID-19 vaccination in the third trimester was associated with a decreased risk of preterm birth (<37 weeks) (RR 0.85 [95% CI 0.74 to 0.98]), 5-min Apgar <7 (RR 0.87 [95% CI 0.78 to 0.97]) and neonatal intensive care unit (NICU) admission (RR 0.90 [95% CI 0.86 to 0.95]). The inverse associations were also found in analysis of one-dose vaccination during pregnancy and the risk of miscarriage (RR 0.83 [95% CI 0.72 to 0.96]) and preterm birth (<37 weeks) (RR 0.90 [95% CI 0.80 to 1.00]) and two-dose vaccination during pregnancy and the risk of NICU admission (RR 0.86 [95% CI 0.76 to 0.96]). COVID-19 vaccination during pregnancy does not increase the risk of negative outcomes for the mother or baby.

SARS-CoV-2 infection in IVF-conceived early pregnancy and the risk of miscarriage: a matched retrospective cohort study

STUDY QUESTION

Is SARS-CoV-2 infection in IVF-conceived early pregnancy associated with a higher risk of miscarriage?

SUMMARY ANSWER

Infection with SARS-CoV-2 during early pregnancy in women conceiving by IVF may not be associated with an increased rate of miscarriage.

WHAT IS KNOWN ALREADY

In naturally conceived pregnancies, most findings have shown that SARS-CoV-2 infection does not increase the risk of miscarriage, while some studies have shown that SARS-CoV-2 infection is associated with a higher risk of miscarriage.

STUDY DESIGN SIZE DURATION

A matched retrospective cohort study was conducted in a tertiary hospital-based reproductive medicine center. The infection group included women who contracted coronavirus disease 2019 (COVID-19) before 20 weeks gestation from 6 December 2022 to 10 January 2023. Each infected woman was matched with three historical control subjects from 1 January 2018 to 31 May 2022.

PARTICIPANTS/MATERIALS SETTING METHODS

The infection group was matched with historical control subjects based on female age (±1 year), number of gestational sacs, number of previous miscarriages, BMI (±2 kg/cm2), main causes of infertility, gestational week, and fresh versus frozen embryo transfer.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 150 pregnant women infected with COVID-19 before 20 weeks of gestation were included in the infection group, which was matched at a 3:1 ratio with 450 historically pregnant controls. There were no significant differences in age, BMI, and endometrial thickness between the two groups. The overall incidence of miscarriage was not significantly different between the infection group and the control group (4.7% versus 5.8%, P = 0.68). When the infection group was stratified into three subgroups based on the gestational age at the onset of infection (0-7 + 6, 8-11 + 6, and 12-19 + 6 weeks), no significant differences were observed in the incidence of miscarriage between the infection group and the matched control group in any of the subgroups (9.8% versus 13.8%, P = 0.60; 5.4% versus 4.5%, P = 1.00; and 1.4% versus 1.9%, P = 1.00, respectively).

LIMITATIONS REASONS FOR CAUTION

The major limitation of this study is the relatively small sample size; therefore, caution is suggested when drawing any definitive conclusions. Nonetheless, our study is the largest sample study of the influence of COVID-19 infection on the miscarriage rate in early pregnancy after IVF.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings may provide important insights for reproductive physicians and obstetricians during preconception and early pregnancy counseling.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by the Natural Science Foundation of Guangdong Province (No. 2023A1515010250). The authors report no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Miscarriage after SARS-CoV-2 vaccination: A population-based cohort study

OBJECTIVE

To evaluate the risk of miscarriage following SARS-CoV-2 vaccination, while accounting for the competing risk of induced abortion.

DESIGN

Population-based cohort study.

SETTING

Ontario, Canada.

PARTICIPANTS

Women aged 15-50 years with a confirmed pregnancy at ≤19 completed weeks' gestation.

METHODS

Exposure to first SARS-CoV-2 vaccination, handled in a time-varying manner, was defined as (i) unvaccinated, (ii) remotely vaccinated >28 days before the estimated conception date or (iii) recently vaccinated ≤28 days before conception and up to 120 days after conception.

MAIN OUTCOME MEASURES

The outcome was miscarriage, occurring between the estimated date of conception and up to 19 completed weeks of pregnancy. Fine-Grey hazard models, accounting for the competing risk of induced abortion, generated hazard ratios (aHR), adjusted for socio-demographic factors, comorbidities, and biweekly periods.

RESULTS

Included were 246 259 pregnant women, of whom 34% received a first SARS-CoV-2 vaccination. Miscarriage occurred at a rate of 3.6 per 10 000 person-days among remotely vaccinated women and 3.2 per 10 000 person-days among those recently vaccinated, in contrast to a rate of 1.9 per 10 000 person-days among unvaccinated women, with corresponding aHR of 0.98 (95% confidence interval [CI] 0.91-1.07) and 1.00 (95% CI 0.93-1.08).

CONCLUSIONS

SARS-CoV-2 vaccination was not associated with miscarriage while accounting for the competing risk of induced abortion. This study reiterates the importance of including pregnant women in new vaccine clinical trials and registries, and the rapid dissemination of vaccine safety data.

[SARS-CoV-2 Infection in Pregnancy and Incidence of Congenital Malformations - is there a Correlation? Analysis of 8032 Pregnancies from the CRONOS Registry]

BACKGROUND

Based on single case reports, the COVID-19 Related Obstetric and Neonatal Outcome Study (CRONOS) registry, sponsored by the German Society for Perinatal Medicine (DGPM), investigated the likelihood that SARS-CoV-2 infections of the mother in (early) pregnancy cause embryopathies and/or fetopathies.

MATERIAL/METHODS

The CRONOS registry enrolled a total of 8032 women with confirmed SARS-CoV-2 infection during pregnancy at more than 130 participating hospitals from April 2020 to February 2023. Both maternal and fetal data were documented and the anonymized multicenter data were analyzed.

RESULTS

Of 7142 fully documented pregnancies (including postnatal data), 140 showed congenital malformations. 8.57% of the mothers had had a SARS-CoV-2-infection in the 1st trimester and 36.43% in the 2nd trimester. In 66 cases with congenital malformations (47.14%), the malformation was only detected after the diagnosis of a maternal SARS-CoV-2 infection. The overall prevalence of congenital malformations in this cohort was 1.96%, compared to a prevalence of 2.39% reported in the EUROCAT (European network of population-based registries for the epidemiological surveillance of congenital anomalies) pre-pandemic registry between 2017-2019.

DISCUSSION

Our multicenter data argue against a link between maternal SARS-CoV-2 infection in early pregnancy and congenital malformation.

Assisted reproduction after SARS-CoV-2-infection: results of a single-center cohort-study

PURPOSE

The effects of SARS-CoV-2 infections on the outcome of assisted reproduction techniques (ART) were studied in a retrospective cohort study.

METHODS

The outcome of 1581 treatment cycles with embryo transfer at a university fertility center in Germany was compared in years before and during the COVID-19 pandemic. For 335 treatment cycles in 2022 a detailed analysis was carried out depending on infection and immunization status of both partners.

RESULTS

ART cycles did not differ in most of the parameters examined between 2018-2022. In spite of comparable clinical pregnancy rates, there was a significantly higher miscarriage rate at 34.6% (27/78) in 2022, compared to 19.7% (29/147) in the pre-pandemic years of 2018-2019 (p = 0.014). In 37.0% of the treatment cycles (124/335) 2022 at least one partner reported a SARS-CoV-2-Infection 6 months before ART, mostly with the virus variant Omicron. Clinical pregnancy rates were lower in cycles without infection. Comparing women with confirmed infection to no infection, a significantly higher risk of miscarriage was seen (62.5% vs. 26.2%, p = 0.009). In treatment cycles of partners with basic immunization against SARS-CoV-2 a statistically significant increase of pregnancy rates was seen comparing to cycles with both unvaccinated partners (p = 0.011).

CONCLUSION

The results indicate a negative impact of SARS-CoV-2-infections up to 6 months on ART treatment, in particular an increased risk of miscarriage. Vaccination was associated with a better outcome of ART treatment.

The risk of miscarriage after COVID-19 vaccination before and during pregnancy

PURPOSE

Pregnant women are at higher risk of severe illness and adverse pregnancy outcomes due to a SARS-CoV-2 infection, which can be prevented by vaccination. Observational studies are needed to ascertain the safety of COVID-19 vaccination during pregnancy. We aimed to determine whether COVID-19 vaccination before and during pregnancy is associated with the risk of miscarriage.

METHODS

In this cohort study, we included 4640 pregnant women (mean age: 32.8 ± 3.7 years) from the Dutch Pregnancy Drug Register between February 2021 and August 2022. Information on COVID-19 vaccinations, miscarriage, and confounders was self-reported, using web-based questionnaires. The hazard ratio (HR) of miscarriage (in gestational weeks 6-20) after a COVID-19 vaccination, was estimated using the survival analyses. A COVID-19 vaccination during pregnancy (≥1 COVID-19 vaccination between week 2 and 20 of pregnancy) was included as a time-dependent exposure and vaccination prior to pregnancy was included as a binary exposure.

RESULTS

A total of 3202 pregnant women (69%) received ≥1 COVID-19 vaccine in gestational week 2-20. We observed no association of vaccination during pregnancy with the risk of miscarriage (adjusted HR = 1.29, 95% CI = 0.93-1.74). Vaccination prior to pregnancy, however, was associated with a decreased risk of miscarriage (adjusted HR = 0.69, 95% CI = 0.48-0.99).

CONCLUSIONS

We demonstrated that COVID-19 vaccination during pregnancy is not associated with an increased risk of miscarriage in gestational weeks 6-20. This study adds to the growing body of evidence demonstrating the safety of COVID-19 vaccination during pregnancy.

Vaccination, immunity, and the changing impact of COVID-19 on infant health

In utero exposure to COVID-19 infection may lead to large intergenerational health effects. The impact of infection exposure has likely evolved since the onset of the pandemic as new variants emerge, immunity from prior infection increases, vaccines become available, and vaccine hesitancy persists, such that when infection is experienced is as important as whether it is experienced. We examine the changing impact of COVID-19 infection on preterm birth and the moderating role of vaccination. We offer the first plausibly causal estimate of the impact of maternal COVID-19 infection by using population data with no selectivity, universal information on maternal COVID-19 infection, and linked sibling data. We then assess change in this impact from 2020 to 2023 and evaluate the protective role of COVID-19 vaccination on infant health. We find a substantial adverse effect of prenatal COVID-19 infection on the probability of preterm birth. The impact was large during the first 2 y of the pandemic but had fully disappeared by 2022. The harmful impact of COVID-19 infection disappeared almost a year earlier in zip codes with high vaccination rates, suggesting that vaccines might have prevented thousands of preterm births. The findings highlight the need to monitor the changing consequences of emerging infectious diseases over time and the importance of mitigation strategies to reduce the burden of infection on vulnerable populations.

A prospective cohort study of preconception COVID-19 vaccination and miscarriage

STUDY QUESTION

To what extent is preconception maternal or paternal coronavirus disease 2019 (COVID-19) vaccination associated with miscarriage incidence?

SUMMARY ANSWER

COVID-19 vaccination in either partner at any time before conception is not associated with an increased rate of miscarriage.

WHAT IS KNOWN ALREADY

Several observational studies have evaluated the safety of COVID-19 vaccination during pregnancy and found no association with miscarriage, though no study prospectively evaluated the risk of early miscarriage (gestational weeks [GW] <8) in relation to COVID-19 vaccination. Moreover, no study has evaluated the role of preconception vaccination in both male and female partners.

STUDY DESIGN, SIZE, DURATION

An Internet-based, prospective preconception cohort study of couples residing in the USA and Canada. We analyzed data from 1815 female participants who conceived during December 2020-November 2022, including 1570 couples with data on male partner vaccination.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Eligible female participants were aged 21-45 years and were trying to conceive without use of fertility treatment at enrollment. Female participants completed questionnaires at baseline, every 8 weeks until pregnancy, and during early and late pregnancy; they could also invite their male partners to complete a baseline questionnaire. We collected data on COVID-19 vaccination (brand and date of doses), history of SARS-CoV-2 infection (yes/no and date of positive test), potential confounders (demographic, reproductive, and lifestyle characteristics), and pregnancy status on all questionnaires. Vaccination status was categorized as never (0 doses before conception), ever (≥1 dose before conception), having a full primary sequence before conception, and completing the full primary sequence ≤3 months before conception. These categories were not mutually exclusive. Participants were followed up from their first positive pregnancy test until miscarriage or a censoring event (induced abortion, ectopic pregnancy, loss to follow-up, 20 weeks' gestation), whichever occurred first. We estimated incidence rate ratios (IRRs) for miscarriage and corresponding 95% CIs using Cox proportional hazards models with GW as the time scale. We used propensity score fine stratification weights to adjust for confounding.

MAIN RESULTS AND THE ROLE OF CHANCE

Among 1815 eligible female participants, 75% had received at least one dose of a COVID-19 vaccine by the time of conception. Almost one-quarter of pregnancies resulted in miscarriage, and 75% of miscarriages occurred <8 weeks' gestation. The propensity score-weighted IRR comparing female participants who received at least one dose any time before conception versus those who had not been vaccinated was 0.85 (95% CI: 0.63, 1.14). COVID-19 vaccination was not associated with increased risk of either early miscarriage (GW: <8) or late miscarriage (GW: 8-19). There was no indication of an increased risk of miscarriage associated with male partner vaccination (IRR = 0.90; 95% CI: 0.56, 1.44).

LIMITATIONS, REASONS FOR CAUTION

The present study relied on self-reported vaccination status and infection history. Thus, there may be some non-differential misclassification of exposure status. While misclassification of miscarriage is also possible, the preconception cohort design and high prevalence of home pregnancy testing in this cohort reduced the potential for under-ascertainment of miscarriage. As in all observational studies, residual or unmeasured confounding is possible.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study to evaluate prospectively the relation between preconception COVID-19 vaccination in both partners and miscarriage, with more complete ascertainment of early miscarriages than earlier studies of vaccination. The findings are informative for individuals planning a pregnancy and their healthcare providers.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the National Institute of Health [R01-HD086742 (PI: L.A.W.); R01-HD105863S1 (PI: L.A.W. and M.L.E.)], the National Institute of Allergy and Infectious Diseases (R03-AI154544; PI: A.K.R.), and the National Science Foundation (NSF-1914792; PI: L.A.W.). The funders had no role in the study design, data collection, analysis and interpretation of data, writing of the report, or the decision to submit the paper for publication. L.A.W. is a fibroid consultant for AbbVie, Inc. She also receives in-kind donations from Swiss Precision Diagnostics (Clearblue home pregnancy tests) and Kindara.com (fertility apps). M.L.E. received consulting fees from Ro, Hannah, Dadi, VSeat, and Underdog, holds stock in Ro, Hannah, Dadi, and Underdog, is a past president of SSMR, and is a board member of SMRU. K.F.H. reports being an investigator on grants to her institution from UCB and Takeda, unrelated to this study. S.H.-D. reports being an investigator on grants to her institution from Takeda, unrelated to this study, and a methods consultant for UCB and Roche for unrelated drugs. The authors report no other relationships or activities that could appear to have influenced the submitted work.

TRIAL REGISTRATION NUMBER

N/A.

Safety of COVID-19 vaccination in pregnant women and their neonatal outcome: a narrative Review

BACKGROUND

Even through the fact that pregnant women are more and more severely infected with COVID-19 disease, there are still doubts about vaccinating these people due to the lack of sufficient evidence base information. So in this systematic review, we decided to study vaccinated and unvaccinated pregnant women regarding maternal, fetal and neonatal complications and outcomes.

THE STRATEGY OF SEARCHING

Between 30 December 2019 and 15 October 2021, electronic searches were performed on the databases of PubMed, Scopus, Google Scholar, and Cochrane library by searching in English and free full text. Keywords searched included these: maternal outcome, neonatal outcome, pregnancy, and COVID-19 vaccination. Among 451 articles, finally, seven studies were included to study pregnancy outcomes in vaccinated women compared to unvaccinated for systematic review purposes.

RESULTS

In this study 30257 vaccinated women in their third trimester compared to 132339 unvaccinated women in terms of age, the root of delivery, neonatal adverse outcomes. There were no significant differences between two groups in terms of: IUFD, and 1 min Apgar score, C/S rate, and NICU admission between the two groups, however, the rate of SGA, IUFD, and also neonatal jaundice, asphyxia, and hypoglycemia was more significant in the unvaccinated group comparing to the vaccinated group as a result. Among them, the chance of preterm labor pain was reported more among vaccinated patients. Emphasizing that, except 7.3% of the case population, everyone in the second and third trimesters had been vaccinated with mRNA COVID-19 vaccines.

CONCLUSION

COVID-19 vaccination during the second and third trimesters appears to be the right choice due to the immediate impact of COVID-19 antibodies on the developing fetus and formation of neonatal prophylaxis, as well as the absence of adverse outcomes for both the fetus and mothers.

Review of short-term and long-term adverse effects of covid-19 vaccination during pregnancy

BACKGROUND

The covid-19 pandemic sparked a debate about the safety of vaccines during pregnancy. However, pregnant women were excluded from the Pfizer-BioNTech vaccine phase 3 trials. As two years have passed since the first Covid-19 vaccine and more studies have been conducted, we want to evaluate the scientific literature to determine any actual risks in taking the vaccine during pregnancy.

METHODS

We conducted literature research using PubMed and Google Scholar databases from January to April 2023. As the review considers short- and long-term adverse effects it was divided into two parts. The first part was conducted as a systematic review. The second concerning long-term negative effects due to lack of research is a literature review. The inclusion criteria for the systematic review part were singleton pregnancies, women vaccinated during pregnancy, and studies from 2020 and later. The most common short-term pregnancy adverse effects were included in the search: preterm delivery, small gestation age, intrauterine death, congenital defects, stillborn, fetal growth retardation, spontaneous abortion. Maternal immune activation was the primary concern for the long-term adverse effects and whether vaccination could cause it. The search terms included maternal immune activation, fetal neurodevelopment, neuropsychiatric disorders and the studies used were from 2019.

RESULTS

Most studies showed no significant difference in short-term adverse effects between vaccinated and non-vaccinated women and their fetuses. However, the literature is insufficient to evaluate possible long-term adverse effects.

CONCLUSION

Available evidence supports the safety of administering SARS-CoV-2 vaccines to pregnant women, but further systematic reviews and meta-analyses are essential. Maternal immune activation caused by vaccination may impact a child's neurodevelopment and should be a concern for future studies.

Risk of congenital malformation after first trimester mRNA COVID-19 vaccine exposure in pregnancy: the COVI-PREG prospective cohort

OBJECTIVES

This study aimed to evaluate the risk of congenital malformation among pregnant women exposed to the mRNA COVID-19 vaccines during the first trimester of pregnancy, which is a developmental period where the foetus is at risk of teratogenicity.

METHODS

Pregnant women were prospectively enrolled from March 2021 to March 2022, at the time of COVID-19 vaccination. Pregnant women exposed to at least one dose of mRNA COVID-19 vaccine from conception to 11 weeks of gestations and 6 days were compared with pregnant women exposed to the vaccine from 12 weeks to the end of pregnancy. The primary outcome was a confirmed congenital malformation at birth.

RESULTS

A total of 1450 pregnant women were enrolled including 124 in the first trimester and 1326 in the second and third trimester. The overall proportion of congenital malformation was 0.81% (n = 1/124; 95% CI: 0.02-4.41) and 0.83% (n = 11/1326; 95% CI: 0.41-1.48) among pregnant exposed to the COVID-19 vaccine during the first and second/third trimester, respectively. First trimester exposure was not associated with a higher risk of congenital malformation with a relative risk of 0.89 (95% CI: 0.12-6.80) with no significant changes after adjustment through exploratory analysis.

CONCLUSIONS

Pregnant women exposed to mRNA COVID-19 vaccine before 12 weeks of gestation did not have an increased risk of congenital malformation compared with women exposed outside the teratogenic window. Because vaccination is safe and effective, emphasis must be placed on promoting vaccination during pregnancy.

Predictors of incomplete COVID-19 vaccine schedule among adults in Scotland: Two retrospective cohort analyses of the primary schedule and third dose

BACKGROUND

Vaccination continues to be the key public health measure for preventing severe COVID-19 outcomes. Certain groups may be at higher risk of incomplete vaccine schedule, which may leave them vulnerable to COVID-19 hospitalisation and death.

AIM

To identify the sociodemographic and clinical predictors for not receiving a scheduled COVID-19 vaccine after previously receiving one.

METHODS

We conducted two retrospective cohort studies with ≥3.7 million adults aged ≥18 years in Scotland. Multivariable logistic regression was used to estimate adjusted odds ratios (aOR) of not receiving a second, and separately a third dose between December 2020 and May 2022. Independent variables included sociodemographic and clinical factors.

RESULTS

Of 3,826,797 people in the study population who received one dose, 3,732,596 (97.5%) received two doses, and 3,263,153 (86.5%) received all doses available during the study period. The most strongly associated predictors for not receiving the second dose were: being aged 18-29 (reference: 50-59 years; aOR:4.26; 95% confidence interval (CI):4.14-4.37); hospitalisation due to a potential vaccine related adverse event of special interest (AESI) (reference: not having a potential AESI, aOR:3.78; 95%CI: 3.29-4.35); and living in the most deprived quintile (reference: least deprived quintile, aOR:3.24; 95%CI: 3.16-3.32). The most strongly associated predictors for not receiving the third dose were: being 18-29 (reference: 50-59 years aOR:4.44; 95%CI: 4.38-4.49), living in the most deprived quintile (reference: least deprived quintile aOR:2.56; 95%CI: 2.53-2.59), and Black, Caribbean, or African ethnicity (reference: White ethnicity aOR:2.38; 95%CI: 2.30-2.46). Pregnancy, previous vaccination with mRNA-1273, smoking history, individual and household severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positivity, and having an unvaccinated adult in the household were also associated with incomplete vaccine schedule.

CONCLUSION

We observed several risk factors that predict incomplete COVID-19 vaccination schedule. Vaccination programmes must take immediate action to ensure maximum uptake, particularly for populations vulnerable to severe COVID-19 outcomes.

Neonatal and maternal outcomes following SARS-CoV-2 infection and COVID-19 vaccination: a population-based matched cohort study

Understanding the impact of SARS-CoV-2 infection and COVID-19 vaccination in pregnancy on neonatal and maternal outcomes informs clinical decision-making. Here we report a national, population-based, matched cohort study to investigate associations between SARS-CoV-2 infection and, separately, COVID-19 vaccination just before or during pregnancy and the risk of adverse neonatal and maternal outcomes among women in Scotland with a singleton pregnancy ending at ≥20 weeks gestation. Neonatal outcomes are stillbirth, neonatal death, extended perinatal mortality, preterm birth (overall, spontaneous, and provider-initiated), small-for-gestational age, and low Apgar score. Maternal outcomes are admission to critical care or death, venous thromboembolism, hypertensive disorders of pregnancy, and pregnancy-related bleeding. We use conditional logistic regression to derive odds ratios adjusted for socio-demographic and clinical characteristics (aORs). We find that infection is associated with an increased risk of preterm (aOR=1.36, 95% Confidence Interval [CI] = 1.16-1.59) and very preterm birth (aOR = 1.90, 95% CI 1.20-3.02), maternal admission to critical care or death (aOR=1.72, 95% CI = 1.39-2.12), and venous thromboembolism (aOR = 2.53, 95% CI = 1.47-4.35). We find no evidence of increased risk for any of our outcomes following vaccination. These data suggest SARS-CoV-2 infection during pregnancy is associated with adverse neonatal and maternal outcomes, and COVID-19 vaccination remains a safe way for pregnant women to protect themselves and their babies against infection.

Effectiveness and safety of coronavirus disease 2019 vaccines

PURPOSE OF REVIEW

To review and summarise recent evidence on the effectiveness of coronavirus disease 2019 (COVID-19) vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and COVID-19 hospitalisation and death in adults as well as in specific population groups, namely pregnant women, and children and adolescents. We also sought to summarise evidence on vaccine safety in relation to cardiovascular and neurological complications. In order to do so, we drew primarily on evidence from two our own data platforms and supplement these with insights from related large population-based studies and systematic reviews.

RECENT FINDINGS

All studies showed high vaccine effectiveness against confirmed SARS-CoV-2 infection and in particular against COVID-19 hospitalisation and death. However, vaccine effectiveness against symptomatic COVID-19 infection waned over time. These studies also found that booster vaccines would be needed to maintain high vaccine effectiveness against severe COVID-19 outcomes. Rare cardiovascular and neurological complications have been reported in association with COVID-19 vaccines.

SUMMARY

The findings from this paper support current recommendations that vaccination remains the safest way for adults, pregnant women, children and adolescents to be protected against COVID-19. There is a need to continue to monitor the effectiveness and safety of COVID-19 vaccines as these continue to be deployed in the evolving pandemic.

Coronavirus Disease 2019 (COVID-19) Vaccination in Pregnancy

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in pregnancy is associated with significant maternal morbidity and mortality, and its risks can be mitigated with coronavirus disease 2019 (COVID-19) vaccination. Vaccination against COVID-19 in pregnancy results in protection against both maternal and neonatal SARS-CoV-2 infection, as well as maternal critical illness. Vaccination during pregnancy is safe, with no documented risks of pregnancy loss, preterm delivery, congenital anomalies, or other adverse perinatal outcomes. For these reasons, COVID-19 vaccination is recommended in pregnancy by the Centers for Disease Control and Prevention, the American College of Obstetricians and Gynecologists, and the Society for Maternal-Fetal Medicine, as well as other national and international professional organizations. In this review, we will summarize the published literature demonstrating the benefit and safety of these vaccines.

A population-based matched cohort study of major congenital anomalies following COVID-19 vaccination and SARS-CoV-2 infection

Evidence on associations between COVID-19 vaccination or SARS-CoV-2 infection and the risk of congenital anomalies is limited. Here we report a national, population-based, matched cohort study using linked electronic health records from Scotland (May 2020-April 2022) to estimate the association between COVID-19 vaccination and, separately, SARS-CoV-2 infection between six weeks pre-conception and 19 weeks and six days gestation and the risk of [1] any major congenital anomaly and [2] any non-genetic major congenital anomaly. Mothers vaccinated in this pregnancy exposure period mostly received an mRNA vaccine (73.7% Pfizer-BioNTech BNT162b2 and 7.9% Moderna mRNA-1273). Of the 6731 babies whose mothers were vaccinated in the pregnancy exposure period, 153 had any anomaly and 120 had a non-genetic anomaly. Primary analyses find no association between any vaccination and any anomaly (adjusted Odds Ratio [aOR] = 1.01, 95% Confidence Interval [CI] = 0.83-1.24) or non-genetic anomalies (aOR = 1.00, 95% CI = 0.81-1.22). Primary analyses also find no association between SARS-CoV-2 infection and any anomaly (aOR = 1.02, 95% CI = 0.66-1.60) or non-genetic anomalies (aOR = 0.94, 95% CI = 0.57-1.54). Findings are robust to sensitivity analyses. These data provide reassurance on the safety of vaccination, in particular mRNA vaccines, just before or in early pregnancy.