Effectiveness of Maternal Vaccination with mRNA COVID-19 Vaccine During Pregnancy Against COVID-19-Associated Hospitalization in Infants Aged <6 Months - 17 States, July 2021-January 2022

Vaccination in pregnancy to protect the newborn

Infectious diseases pose a particular risk to newborns and there is a global need to protect this vulnerable group. Because of the challenges of developing vaccines that are effective in newborns, only the hepatitis B and tuberculosis vaccines are given in the first 28 days of life, and even those vaccines are mainly only offered to high-risk groups. Maternal antibodies cross the placenta and can afford some protection to the newborn, so an alternative strategy is vaccination in pregnancy. This approach has been successfully used to protect newborns against tetanus and pertussis, and vaccines that are primarily offered to protect the mother during pregnancy, such as influenza and COVID-19 vaccines, also provide some protection to newborns. A respiratory syncytial virus vaccine has recently been approved for use in pregnancy to protect newborns, and a new vaccine that will be offered during pregnancy to prevent Group B Streptococcus infection in infants is on the horizon. Here, we discuss the current vaccines that are offered during pregnancy and to newborns, the vaccines in development for future use in these groups and the challenges that remain concerning the delivery and uptake of such vaccines.

Is trust a zero-sum game? What happens when institutional sources get it wrong

Trust in mainstream institutions is declining while people are increasingly turning to alternative media and conspiracy theories. Previous research has suggested that these trends may be linked, but the dynamics of trust across multiple sources has received little investigation. Is trust a neutral process, where each source is judged independently, is it a zero-sum competition, where a loss for one side is a gain for the other, or does losing trust in one source in foster a more generalized sense of distrust? Across three experimental studies (N = 2,951) we examined how people react when a source makes a serious error, testing four potential models of trust dynamics. We found that regardless of whether the outlet is mainstream, counter-mainstream, or neutral, trust drops for the erring source but does not rise for its competitors. This was the case in the context of both food regulations and COVID-19 precautions. Such a pattern suggest that each source may be judged independently of others. However, in several cases, an error made by one source led to a loss of trust in all sources, suggesting that rather than choosing sides between competing sources, people are also judging the media landscape as a whole to discern if it is feasible to find trustworthy information. However, correlational data did also find that the more people saw a source as politicized, the less they trusted that source and the more they trusted its competitors.

COVID-19 vaccination rates among pregnant women in France: A nationwide cohort study

BACKGROUND

Pregnant women are at an elevated risk for severe COVID-19, but nationwide rates of vaccination and its timing during pregnancy are not well documented in France.

OBJECTIVES

To assess COVID-19 vaccination rates among pregnant women in France, compare them to those of the general population, and analyse factors associated with vaccination status and timing.

METHODS

A nationwide study using the EPI-MERES register, which includes all 1,203,454 pregnant women who delivered between April 2021 and December 2022 in France. Standardization by age and social index was used to compare vaccination rates with those of the general female population. Associations with sociodemographic factors, pregnancy monitoring indicators, and pre-existing comorbidities were measured using multivariable logistic regression.

RESULTS

Overall, 52 % of pregnant women received at least one vaccine dose, with 62.1 % vaccinated before conception and 8.2 %, 20.9 %, and 8.8 % vaccinated in the 1st, 2nd, and 3rd trimester, respectively. Vaccination rates initially lagged behind those of the general population but converged by June 2022, with a six-month lag. Younger and more socially deprived women were less highly vaccinated. Unvaccinated women were more likely to be in their third pregnancy (aOR, 1.21 [1.19-1.22]), had fewer ultrasound scans (aOR, 0.71 [0; 70-0.73]), and less often took folic acid (aOR, 0.73 [0.72-0.74]). Women with comorbidities, such as obesity, diabetes, hypertension, antidepressant use, or chronic respiratory disease, were less likely to be unvaccinated (aORs ranged from 0.69 to 0.89).

CONCLUSIONS

Pregnant women in France were less highly vaccinated than the general population during crucial pandemic periods but eventually reached similar vaccination rates. Socioeconomic status and the level of prenatal care were strongly associated with low vaccine uptake. This should be a focus for future interventions and policy adjustments across all segments of this population.

The effect of coronavirus disease 2019 vaccination on pregnant women: A scoping review

Background

Globally, reports have shown that pregnant women refuse to receive the coronavirus disease 2019 (COVID-19) vaccine. This has posed a significant concern given the global impact of the COVID-19 pandemic.

Aim

This study aims to explore the current evidence on the effect of COVID-19 vaccination on pregnant women.

Method

A scoping review was conducted using Levac et al.'s five-stage framework. Relevant articles were searched in the Web of Science, PubMed, Scopus and EBSCOhost (CINAHL) databases. The identified articles were screened based on predetermined inclusion and exclusion criteria. Data from the selected articles were charted and summarised into meaningful units.

Results

Twelve articles from developed countries were included in the review. Studies have reported that COVID-19 vaccination during pregnancy is generally safe and does not increase the risk of pregnancy complications. There was no significant difference in delivery outcomes between vaccinated and unvaccinated women. Neonatal outcomes were not affected by the vaccination. However, one study identified a potential risk of spontaneous abortion between 6 and 9 weeks of gestation among vaccinated women.

Conclusion

Coronavirus disease 2019 vaccination is considered safe during pregnancy. While some studies have identified potential associations with certain conditions, the overall benefits of vaccination outweigh the risks. Continued monitoring of the safety and effectiveness of COVID-19 vaccines during pregnancy is recommended. Pregnant women should consult healthcare providers to make informed decisions regarding vaccination.

Contribution

The findings of this review may assist in alleviating anxiety and reducing vaccine hesitancy among pregnant women.

Maternal Preconception COVID-19 Vaccination and Its Protective Effect on Infants after a Breakthrough Infection during Pregnancy

BACKGROUND AND AIMS

The transplacental vertical transfer of maternal antibodies was determined to be a crucial factor in conferring protective immunity to infants following delivery, and this study aimed to evaluate the protective effect of maternal preconception COVID-19 vaccination on infants.

METHODS

A prospective cohort study was conducted at the National Clinical Medical Research Center for Child Health and Diseases in Chongqing, China, spanning from July 2022 to April 2023. The study included infants from mothers with a preconception COVID-19 vaccination and (or) a SARS-CoV-2 infection during pregnancy. Titers of SARS-CoV-2 immunoglobulin G (IgG) and cross-neutralizing activity against SARS-CoV-2 variants were detected.

RESULTS

In this cohort study comprising 158 infants, it was observed that infants born to mothers who experienced a pregnancy-related breakthrough infection following a preconception vaccination had the highest titers of SARS-CoV-2 IgG and cross-neutralizing antibody activity against different variants compared to those with either of these factors alone. The transplacental vertical transmission of anti-SARS-CoV-2 antibodies decreased significantly with increasing age, from 3.16 ODs at birth to 2.29 ODs at two months, and persisted for approximately four months after birth. The predominant subclass of passively transmitted antibodies via the placenta was found to be IgG1, and a positive correlation was observed between the titers of SARS-CoV-2 IgG and IgG1 (R = 0.59, p < 0.001; Slope: 0.49 ± 0.070, p < 0.001).

CONCLUSIONS

Maternal preconception COVID-19 vaccination represents a promising immunological strategy for conferring postnatal protection to infants, especially during the period of heightened risk of exposure to SARS-CoV-2 infection. It is imperative to underscore the significance of vaccination for women who are preparing to become pregnant or are pregnant, and concerted efforts must be made to promote vaccination among eligible women.

Non-Viral RNA Delivery During Pregnancy: Opportunities and Challenges

During pregnancy, the risk of maternal and fetal adversities increases due to physiological changes, genetic predispositions, environmental factors, and infections. Unfortunately, treatment options are severely limited because many essential interventions are unsafe, inaccessible, or lacking in sufficient scientific data to support their use. One potential solution to this challenge may lie in emerging RNA therapeutics for gene therapy, protein replacement, maternal vaccination, fetal gene editing, and other prenatal treatment applications. In this review, the current landscape of RNA platforms and non-viral RNA delivery technologies that are under active development for administration during pregnancy is explored. Advancements of pregnancy-specific RNA drugs against SARS-CoV-2, Zika, influenza, preeclampsia, and for in-utero gene editing are discussed. Finally, this study highlights bottlenecks that are impeding translation efforts of RNA therapies, including the lack of accurate cell-based and animal models of human pregnancy and concerns related to toxicity and immunogenicity during pregnancy. Overcoming these challenges will facilitate the rapid development of this new class of pregnancy-safe drugs.

COVID-19 vaccinations pre- and antepartum: a consideration of the evidence and discussion of issues

PURPOSE

The COVID-19 vaccine should be universally offered to pregnant women and women planning pregnancies. This is on the basis that COVID-19 infection can complicate the pregnancy and have adverse health implications in pregnancy, as compared to non-pregnant women, which the vaccine helps to mitigate. This is the recommendation of many governing bodies in medical care. However, certain issues require consideration, which are not discussed in the current guidelines. These include the induction of fever by the vaccines and the role fever can play in teratogenicity, the induction of hyper-coagulable and thrombocytopenic states by the vaccines and other known contraindications to the vaccines. In this article, we develop strategies to minimize risks in these situations. We also discuss the theoretical advantage of calling for a booster COVID-19 vaccinate in all pregnant women in the late second or early third trimester, even if previously immunized, and encourage further research, to investigate the possible benefits of this proposed intervention. This article acts as an educational supplement to help clinicians manage pregnant women and addresses many issues, not discussed in most COVID-19 vaccine recommendations by international societies related to pregnant women.

METHODS

This article is a literature review of the current, limited data. The information extrapolated allowed for suggestions regarding COVID-19 vaccination during pregnancy. RESULTS AND CONCLUSIONS: The study discusses hypothetical issues, to minimize any risks associated with COVID-19, and serves as a compilation of data to further the current literature, in proving that COVID-19 vaccines have minimal risks in pregnancy.

COVID-19-Associated Hospitalizations and Maternal Vaccination Among Infants Aged <6 Months - COVID-NET, 12 States, October 2022-April 2024

Infants aged <6 months are at increased risk for severe COVID-19 disease but are not yet eligible for COVID-19 vaccination; these children depend upon transplacental transfer of maternal antibody, either from vaccination or infection, for protection. COVID-19-Associated Hospitalization Surveillance Network (COVID-NET) data were analyzed to estimate COVID-19-associated hospitalization rates and identify demographic and clinical characteristics and maternal vaccination status of infants aged <6 months hospitalized with laboratory-confirmed COVID-19. During October 2022-April 2024, COVID-NET identified 1,470 COVID-19-associated hospitalizations among infants aged <6 months. COVID-19-associated hospitalization rates among young infants were higher than rates among any other age group, except adults aged ≥75 years, and are comparable to rates among adults aged 65-74 years. The percentage of hospitalized infants whose mothers had been vaccinated during pregnancy was 18% during October 2022-September 2023 and decreased to <5% during October 2023-April 2024. Severe outcomes among infants hospitalized with COVID-19 occurred frequently: excluding newborns hospitalized at birth, approximately one in five young infants hospitalized with COVID-19 required admission to an intensive care unit, nearly one in 20 required mechanical ventilation, and nine infants died during their COVID-19-associated hospitalization. To help protect pregnant persons and infants too young to be vaccinated, prevention for these groups should focus on ensuring that pregnant persons receive recommended COVID-19 vaccines.

Building the U.S. COVID-19 vaccine effectiveness program: Past successes and future directions

COVID-19 vaccines were originally authorized in the United States in December 2020 on the basis of safety, immunogenicity, and clinical efficacy data from randomized controlled trials (RCTs). However, real-world vaccine effectiveness (VE) data are necessary to provide information on how the vaccines work in populations not included in the RCTs (e.g., nursing home residents), against new SARS-CoV-2 variants, with increasing time since vaccination, and in populations with increasing levels of prior infection. The goal of CDC's COVID-19 VE program is to provide timely and robust data to support ongoing policy decisions and implementation of vaccination and includes VE platforms to study the spectrum of illness, from infection to critical illness. Challenges to estimating VE include accurate ascertainment of vaccination history, outcome status, changing rates of prior infection, emergence of new variants, and appropriate interpretation of absolute and relative VE measures. CDC COVID-19 VE platforms have played a pivotal role in numerous vaccine policy decisions since 2021 and will continue to play a key role in future decisions as the vaccine program moves from an emergency response to a routine schedule.

The nurse's role in a patient-centered approach for reducing COVID-19 vaccine hesitancy during pregnancy: An American Academy of Nursing consensus paper

The evidence shows that COVID-19 vaccines can reduce the risks of poor pregnancy outcomes. Yet, reluctance to vaccinate remains high in pregnant populations. In this paper, we take a precision health and patient-centered approach to vaccine hesitancy. We adopted the society-to-cells vaccine hesitancy framework to identify society, community, family, individual, and physiologic factors contributing to COVID-19 vaccine hesitancy in pregnancy. Nurses are particularly well-suited to impact the factors associated with vaccine hesitancy. Because of their proximity to the patient, nurses are positioned to provide individualized, timely health information, and clinical guidelines to assist patients with decision-making related to vaccinations. Recommendations are provided to bolster nurses' engagement in precision health and patient-centered models of care to mitigate COVID-19 vaccine hesitancy in pregnancy.

COVID-19 in Pediatric Populations

The COVID-19 pandemic reshaped the landscape of respiratory viral illnesses, causing common viruses to fade as SARS-CoV-2 took precedence. By 2023, more than 96% of the children in the United States were estimated to have been infected with SARS-CoV-2, with certain genetic predispositions and underlying health conditions posing risk factors for severe disease in children. Children, in general though, exhibit immunity advantages, protecting against aspects of the SARS-CoV-2 infection known to drive increased severity in older adults. Post-COVID-19 complications such as multisystem inflammatory syndrome in children and long COVID have emerged, underscoring the importance of vaccination. Here, we highlight the risks of severe pediatric COVID-19, age-specific immunoprotection, comparisons of SARS-CoV-2 with other respiratory viruses, and factors contributing to post-COVID-19 complications in children.

Neutralizing and binding antibody responses to SARS-CoV-2 with hybrid immunity in pregnancy

Hybrid immunity against SARS-CoV-2 has not been well studied in pregnancy. We conducted a comprehensive analysis of neutralizing antibodies (nAb) and binding antibodies in pregnant individuals who received mRNA vaccination, natural infection, or both. A third vaccine dose augmented nAb levels compared to the two-dose regimen or natural infection alone; this effect was more pronounced in hybrid immunity. There was reduced anti-Omicron nAb, but the maternal-fetal transfer efficiency remained comparable to that of other variants. Vaccine-induced nAbs were transferred more efficiently than infection-induced nAbs. Anti-spike receptor binding domain (RBD) IgG was associated with nAb against wild-type (Wuhan-Hu-1) following breakthrough infection. Both vaccination and infection-induced anti-RBD IgA, which was more durable than anti-nucleocapsid IgA. IgA response was attenuated in pregnancy compared to non-pregnant controls. These data provide additional evidence of augmentation of humoral immune responses in hybrid immunity in pregnancy.

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.

Longer interval between maternal RSV vaccination and birth increases placental transfer efficiency

Background

Respiratory Syncytial Virus (RSV) is associated with significant neonatal and infant morbidity and mortality. Maternal bivalent RSVpreF RSV vaccination to protect neonates and infants was approved in September 2023 for administration between 32+0 and 36+6 weeks to protect neonates and infants. This approved timeframe is narrower than the 24-36 week window evaluated in the clinical trial, due to the possible association between preterm birth and vaccine administration. Currently, data are lacking on how maternal vaccine timing within the approved window affects the transfer of antibodies from mother to fetus, critical information that could influence clinical practice.

Objectives

We sought to examine how gestational age at vaccination and time elapsed from maternal RSV vaccination to delivery impacted transfer of maternal antibodies measured in the umbilical cord at delivery and in peripheral blood of 2-month infants. We also examined differences in maternal and cord RSV antibody levels achieved by vaccination versus natural RSV infection.

Study Design

A prospective cohort study was conducted at two academic medical centers between September 20, 2023 and March 21, 2024, enrolling 124 individuals who received the RSV vaccine during pregnancy. Infant capillary blood was collected at 2 months of age from 29 of the infants. Maternal and cord IgG levels achieved by RSV vaccination were compared to those associated with maternal natural RSV infection, using banked blood from 20 maternal:cord dyads collected prior to the availability of the maternal RSV vaccine. Levels of IgG against RSV strain A2 and B fusion (F) and attachment (G) proteins and against pertussis toxin (as a comparator antigen from a vaccine routinely administered earlier in pregnancy) were measured using a Binding Antibody Multiplex Assay. Differences in titers between vaccination and natural infection were examined using Wilcoxon rank sum test. Differences in cord:maternal transfer ratios and 2-month infant antibody levels by timing of maternal vaccination were evaluated by Kruskal-Wallis testing.

Results

Maternal RSV vaccination resulted in significantly higher maternal and cord anti-F RSV antibody levels than natural infection (5.72 vs 4.82 log 10 MFI, p < 0.0001 maternal; 5.81 vs 5.03 log 10 MFI, p < 0.0001 cord). Maternal vaccination 2-3 weeks and 3-4 weeks prior to delivery was associated with significantly lower cord:maternal transfer ratios than were observed when vaccination occurred > 5 weeks prior to delivery (p = 0.03 for 2-3 weeks, p = 0.007 for 3-4 weeks), and significantly lower transfer ratios than observed for pertussis vaccination administered prior to 30 weeks' gestation (p = 0.008 for 2-3 weeks, p = 0.03 for 3-4 weeks, similar at > 4 weeks).

Conclusions

Vaccine administration earlier in the approved 32-36 week window (at least 5 weeks prior to delivery) results in the highest transplacental transfer of maternal antibodies to the neonate. These results should inform the counseling of pregnant individuals on optimal vaccination timing.

Transfer of Respiratory Syncytial Virus Prefusion F Protein Antibody in Low Birthweight Infants

Background

Respiratory syncytial virus (RSV)-associated lower respiratory tract infection contributes significantly to morbidity/mortality worldwide in low birthweight (LBW) infants (<2500 g). Studies have demonstrated decreased maternal immunoglobulin G (IgG) transfer of various antibodies to LBW infants. We aimed to evaluate naturally acquired RSV anti-prefusion F protein (anti-preF) antibody transfer in pregnancies with LBW versus normal birthweight (NBW) infants.

Methods

In this cohort study conducted among pregnant individuals and their infants, we tested paired maternal and singleton infant cord samples for RSV anti-preF IgG via an electrochemiluminescence immunoassay, using linear regression to evaluate associations between LBW and anti-preF IgG. Covariates included seasonality, insurance, small-for-gestational-age birthweight, and gestational age at delivery.

Results

We tested maternal/cord RSV anti-preF IgG from 54 and 110 pregnancies with LBW and NBW infants, respectively. Of LBW infants, 22 (40.7%) were born both preterm and with small-for-gestational-age birthweight. The median (interquartile range) gestational age at delivery and birthweight were 34.0 (31.7-37.1) weeks and 1902 (1393-2276) g for LBW infants versus 39.1 (38.3-39.9) weeks and 3323 (3109-3565) g for NBW infants (both P < .001). In unadjusted comparisons, preterm infants had significantly lower cord anti-preF IgG levels and cord-maternal IgG ratios compared with full-term infants, while LBW infants had significantly lower cord-maternal IgG ratios than NBW infants (all P < .01). After adjustment for covariates, there was no difference in cord-maternal IgG ratios (β =-0.29 [95% confidence interval, -.63 to .05]) between LBW and NBW infants.

Conclusions

We documented robust transfer of maternal RSV anti-preF IgG in pregnancies with both LBW and NBW infants. Further studies are needed to assess immune protection in at-risk infants.

Protective role of macrophages from maternal-fetal interface in unvaccinated coronavirus disease 2019 pregnant women

Pregnant women represent a high-risk population for Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection. The presence of SARS-CoV-2 has been reported in placenta from infected pregnant women, but whether the virus influences placenta immune response remains unclear. We investigated the properties of maternal-fetal interface macrophages (MFMs) in a cohort of unvaccinated women who contracted coronavirus disease 2019 (COVID-19) during their pregnancy. We reported an infiltration of CD163+ macrophages in placenta from COVID-19 women 19 whereas lymphoid compartment was not affected. Isolated MFMs exhibited nonpolarized activated signature (NOS2, IDO1, IFNG, TNF, TGFB) mainly in women infected during the second trimester of pregnancy. COVID-19 during pregnancy primed MFM to produce type I and III interferon response to SARS-CoV-2 (Wuhan and δ strains), that were unable to elicit this in MFMs from healthy pregnant women. COVID-19 also primed SARS-CoV-2 internalization by MFM in an angiotensin-converting enzyme 2-dependent manner. Activation and recall responses of MFMs were influenced by fetal sex. Collectively, these findings support a role for MFMs in the local immune response to SARS-CoV-2 infection, provide a basis for protective placental immunity in COVID-19, and highlight the interest of vaccination in pregnant women.

IgG antibody levels against the SARS-CoV-2 spike protein in mother-child dyads after COVID-19 vaccination

PURPOSE

We aimed to assess IgG antibodies against the SARS-CoV-2 spike protein (anti-SARS-CoV-2 S IgG) in vaccinated mothers and their infants at delivery and 2-3 months of age.

METHODS

We conducted a prospective study on mothers who received at least one dose of the COVID-19 vaccine (Pfizer-BNT162b2, Moderna mRNA-1273, or Oxford-AstraZeneca ChAdOx1-S) during pregnancy and on their infants. The baseline was at the time of delivery (n = 93), and the end of follow-up was 2 to 3 months post-partum (n = 53). Serum anti-SARS-CoV-2 S IgG titers and ACE2 binding inhibition levels were quantified by immunoassays.

RESULTS

Mothers and infants had high anti-SARS-CoV-2 S IgG titers against the B.1 lineage at birth. However, while antibody titers were maintained at 2-3 months post-partum in mothers, they decreased significantly in infants (p < 0.001). Positive and significant correlations were found between anti-SARS-CoV-2 S IgG titers and ACE2-binding inhibition levels in mothers and infants at birth and 2-3 months post-partum (r > 0.8, p < 0.001). Anti-S antibodies were also quantified for the Omicron variant at 2-3 months post-partum. The antibody titers against Omicron were significantly lower in mothers and infants than those against B.1 (p < 0.001). Again, a positive correlation was observed for Omicron between IgG titers and ACE2-binding inhibition both in mothers (r = 0.818, p < 0.001) and infants (r = 0.386, p < 0.005). Previous SARS-CoV-2 infection and COVID-19 vaccination near delivery positively impacted anti-SARS-CoV-2 S IgG levels.

CONCLUSIONS

COVID-19 mRNA vaccines induce high anti-SARS-CoV-2 S titers in pregnant women, which can inhibit the binding of ACE2 to protein S and are efficiently transferred to the fetus. However, there was a rapid decrease in antibody levels at 2 to 3 months post-partum, particularly in infants.

COVID-19 Vaccination and Reproductive Health: a Comprehensive Review for Healthcare Providers

With all the current misinformation on social media platforms about the COVID-19 vaccine and its potential effects on fertility, it is essential for healthcare providers to have evidenced-based research to educate their patients, especially those who are trying to conceive, of the risks to mothers and fetuses of being unvaccinated. It is well known that COVID-19 infection puts pregnant women at higher risk of complications, including ICU admission, placentitis, stillbirth, and death. In February of 2021, the American College of Obstetricians and Gynecologists (ACOG), the American Society for Reproductive Medicine (ASRM), and the Society for Maternal-Fetal Medicine (SMFM) released a statement denying any link between COVID vaccination and infertility. ASRM later confirmed and stated that "everyone, including pregnant women and those seeking to become pregnant, should get a COVID-19 vaccine". In this review, we aim to provide a compilation of data that denies any link between vaccination and infertility for healthcare providers to be able to educate their patients based on evidence-based medicine. We also reviewed the effect of COVID-19 virus and vaccination on various parameters and processes that are essential to obtaining a successful pregnancy.

Maternal COVID-19 vaccination status and association with neonatal congenital anomalies

Introduction

Despite recommendations for COVID-19 vaccination in pregnant people, the effect of vaccination on neonatal outcomes remains unknown. We sought to determine the association between COVID-19 vaccination status in pregnancy and presence of neonatally diagnosed congenital anomalies.

Methods

A comprehensive vaccine registry was combined with a delivery database to create a cohort including all patients aged 16-55 years with a delivery event between December 10, 2020 and December 31, 2021 at a hospital within the Mayo Clinic Health System. Pregnancy and neonatal outcomes were analyzed in relation to vaccination status and timing, including a composite measure of congenital anomalies diagnosed in neonatal life. Comparisons between cohorts were conducted using chi-square test for categorical and Kruskal-Wallis test for continuous variables. A multivariable logistic regression was modeled to assess the association with congenital anomalies.

Results

5,096 mother-infant pairs were analyzed. A total of 1,158 were vaccinated, with 314 vaccinated in the first trimester. COVID-19 vaccination status, including vaccination during the first trimester of pregnancy, was not associated with an increased risk of composite congenital anomalies. When further examining congenital anomalies by organ system, we did demonstrate a significant difference in eye, ear, face, neck anomalies between vaccinated and not vaccinated groups (Table 3, Not vaccinated = 2.3%, Vaccinated = 3.3%, p-value 0.04) however we did not demonstrate this difference between the 1st trimester and not vaccinated groups (Not vaccinated = 2.3%, 1st Trimester = 2.5%, p-value 0.77). No differences were found between not vaccinated, vaccinated, or 1st trimester vaccinated groups for any other organ systems. There were no differences in birthweight by gestational age, APGAR scores, incidence of NICU admission, or living status of the neonate by vaccination status.

Conclusion

We add additional information regarding the safety of COVID-19 vaccination status and timing as it pertains to neonatal composite congenital anomalies, with no association demonstrated. Our findings agree with prior literature that COVID-19 vaccination is not associated with adverse pregnancy outcomes or small for gestational age neonates. Further research is needed to elucidate the association between COVID-19 vaccination and eye, ear, face, neck, anomalies.

COVID-Vaccines in Pregnancy: Maternal and Neonatal Response over the First 9 Months after Delivery

Vaccination against SARS-CoV-2 has been demonstrated to be safe during gestation. Nevertheless, there are no robust data investigating the entity of maternal antibodies' transmission through the placenta to the newborn and the persistence of the antibodies in babies' serum. The objective of this study is to assess the maternal antibody transmission and kinetics among newborns in the first months of life. Women having received one or two doses of anti-SARS-CoV-2 mRNA-vaccines during pregnancy at any gestational age, and their newborns, were recruited and followed-up over 9 months. Ninety-eight women and 103 babies were included. At birth, we observed a significant positive correlation between maternal and neonatal serum anti-SARS-CoV-2 antibody levels and a significant negative correlation between the time since last dose and antibody levels in mothers with two doses. Over the follow-up, the birth antibody level significantly decreased in time according to the received doses number at 3, 6, and 9 months. During the follow-up, we registered 34 dyad SARS-CoV-2 infection cases. The decreasing trend was slower in the SARS-CoV-2 infection group and among breastfed non-infected babies. Antibodies from maternal anti-SARS-CoV-2 vaccination are efficiently transferred via the placenta and potentially even through breast milk. Among newborns, antibodies show relevant durability in the first months of life.

Placental transfer dynamics and durability of maternal COVID-19 vaccine-induced antibodies in infants

Completion of a COVID-19 vaccination series during pregnancy effectively reduces COVID-19 hospitalization among infants less than 6 months of age. The dynamics of transplacental transfer of maternal vaccine-induced antibodies, and their persistence in infants at 2, 6, 9, and 12 months, have implications for new vaccine development and optimal timing of vaccine administration in pregnancy. We evaluated anti-COVID antibody IgG subclass, Fc-receptor binding profile, and activity against wild-type Spike and RBD plus five variants of concern (VOCs) in 153 serum samples from 100 infants. Maternal IgG1 and IgG3 responses persisted in 2- and 6-month infants to a greater extent than the other IgG subclasses, with high persistence of antibodies binding placental neonatal Fc-receptor and FcγR3A. Lowest persistence was observed against the Omicron RBD-specific region. Maternal vaccine timing, placental Fc-receptor binding capabilities, antibody subclass, fetal sex, and VOC all impact the persistence of antibodies in infants through 12 months of age.

Burden of Respiratory Syncytial Virus-Associated Acute Respiratory Infections During Pregnancy

BACKGROUND

With the licensure of maternal respiratory syncytial virus (RSV) vaccines in Europe and the United States, data are needed to better characterize the burden of RSV-associated acute respiratory infections (ARI) in pregnancy. The current study aimed to determine among pregnant individuals the proportion of ARI testing positive for RSV and the RSV incidence rate, RSV-associated hospitalizations, deaths, and perinatal outcomes.

METHODS

We conducted a systematic review, following PRISMA 2020 guidelines, using 5 databases (Medline, Embase, Global Health, Web of Science, and Global Index Medicus), and including additional unpublished data. Pregnant individuals with ARI who had respiratory samples tested for RSV were included. We used a random-effects meta-analysis to generate overall proportions and rate estimates across studies.

RESULTS

Eleven studies with pregnant individuals recruited between 2010 and 2022 were identified, most of which recruited pregnant individuals in community, inpatient and outpatient settings. Among 8126 pregnant individuals, the proportion with ARI that tested positive for RSV ranged from 0.9% to 10.7%, with a meta-estimate of 3.4% (95% confidence interval [CI], 1.9%-54%). The pooled incidence rate of RSV among pregnant individuals was 26.0 (95% CI, 15.8-36.2) per 1000 person-years. RSV hospitalization rates reported in 2 studies were 2.4 and 3.0 per 1000 person-years. In 5 studies that ascertained RSV-associated deaths among 4708 pregnant individuals, no deaths were reported. Three studies comparing RSV-positive and RSV-negative pregnant individuals found no difference in the odds of miscarriage, stillbirth, low birth weight, and small size for gestational age. RSV-positive pregnant individuals had higher odds of preterm delivery (odds ratio, 3.6 [95% CI, 1.3-10.3]).

CONCLUSIONS

Data on RSV-associated hospitalization rates are limited, but available estimates are lower than those reported in older adults and young children. As countries debate whether to include RSV vaccines in maternal vaccination programs, which are primarily intended to protect infants, this information could be useful in shaping vaccine policy decisions.

COVID-19 booster enhances IgG mediated viral neutralization by human milk in vitro

Background

Facilitated by the inability to vaccinate, and an immature immune system, COVID-19 remains a leading cause of death among children. Vaccinated lactating mothers produce specific SARS-CoV-2 antibodies in their milk, capable of neutralizing the virus in vitro. Our objective for this study is to assess the effect of COVID-19 booster dose on SARS-CoV-2 antibody concentration and viral neutralization in milk, plasma, and infant stool.

Methods

Thirty-nine mothers and 25 infants were enrolled from December 2020 to May 2022. Milk, maternal plasma, and infants' stool were collected at various time-points up to 12 months following mRNA COVID-19 vaccination. A subgroup of 14 mothers received a booster dose. SARS-CoV-2 antibody levels and their neutralization capacities were assessed.

Results

Booster vaccination led to significantly higher IgG levels within human milk and breastfed infants' stool. In vitro neutralization of VSV-gfp-SARS-CoV-2-S-gp, a laboratory safe SARS-CoV-2 like pseudovirus, improved following the booster, with a 90% increase in plasma neutralization and a 60% increase in milk neutralization. We found that post-booster neutralization by human milk was highly correlated to SARS-CoV-2 IgG level. In support of our correlation result, Protein G column depletion of IgG in milk yielded a significant reduction in viral neutralization (p = 0.04).

Discussion

The substantial increase in neutralizing IgG levels in milk and breastfed infants' stool post-booster, coupled with the decrease in milk neutralization capabilities upon IgG depletion, underscores the efficacy of booster doses in augmenting the immune response against SARS-CoV-2 in human milk.

Passive antibody transfer from pregnant women to their fetus are maximized after SARS-CoV-2 vaccination irrespective of prior infection

Background

Pregnancy is associated with a higher risk of adverse symptoms and outcomes for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection for both mother and neonate. Antibodies can provide protection against SARS-CoV-2 infection and are induced in pregnant women after vaccination or infection. Passive transfer of these antibodies from mother to fetus in utero may provide protection to the neonate against infection. However, it is unclear whether the magnitude or quality and kinetics of maternally derived fetal antibodies differs in the context of maternal infection or vaccination.

Objective

We aimed to determine whether antibodies transferred from maternal to fetus differed in quality or quantity between infection- or vaccination-induced humoral immune responses.

Methods

We evaluated 93 paired maternal and neonatal umbilical cord blood plasma samples collected between October 2020 and February 2022 from a birth cohort of pregnant women from New Orleans, Louisiana, with histories of SARS-CoV-2 infection and/or vaccination. Plasma was profiled for the levels of spike-specific antibodies and induction of antiviral humoral immune functions, including neutralization and Fc-mediated innate immune effector functions. Responses were compared between 4 groups according to maternal infection and vaccination.

Results

We found that SARS-CoV-2 vaccination or infection during pregnancy increased the levels of antiviral antibodies compared to naive subjects. Vaccinated mothers and cord samples had the highest anti-spike antibody levels and antiviral function independent of the time of vaccination during pregnancy.

Conclusions

These results show that the most effective passive transfer of functional antibodies against SARS-CoV-2 in utero is achieved through vaccination, highlighting the importance of vaccination in pregnant women.

Maternal pertussis immunization and the blunting of routine vaccine effectiveness: a meta-analysis and modeling study

A key goal of pertussis control is to protect infants too young to be vaccinated, the age group most vulnerable to this highly contagious respiratory infection. In the last decade, maternal immunization has been deployed in many countries, successfully reducing pertussis in this age group. Because of immunological blunting, however, this strategy may erode the effectiveness of primary vaccination at later ages. Here, we systematically reviewed the literature on the relative risk (RR) of pertussis after primary immunization of infants born to vaccinated vs. unvaccinated mothers. The four studies identified had ≤6 years of follow-up and large statistical uncertainty (meta-analysis weighted mean RR: 0.71, 95% CI: 0.38-1.32). To interpret this evidence, we designed a new mathematical model with explicit blunting mechanisms and evaluated maternal immunization's short- and long-term impact on pertussis transmission dynamics. We show that transient dynamics can mask blunting for at least a decade after rolling out maternal immunization. Hence, the current epidemiological evidence may be insufficient to rule out modest reductions in the effectiveness of primary vaccination. Irrespective of this potential collateral cost, we predict that maternal immunization will remain effective at protecting unvaccinated newborns, supporting current public health recommendations.

Timing of Maternal COVID-19 Vaccine and Antibody Concentrations in Infants Born Preterm

Importance

COVID-19 vaccine-derived antibodies in pregnant people may protect infants from severe infection in the first 6 months of life via transplacental antibody transfer. Few data exist on maternally derived SARS-CoV-2 antibodies in preterm compared with full-term infants in association with vaccination timing.

Objective

To compare SARS-CoV-2 anti-Spike (anti-S) antibody levels in preterm and full-term infants in the context of vaccine dose timing before delivery.

Design, Setting, and Participants

This prospective cohort study enrolled pregnant individuals and collected paired maternal and cord blood samples at delivery at the University of Washington between February 1, 2021, and January 31, 2023. Participants who had received at least 2 doses of a messenger RNA COVID-19 vaccine before delivery and did not have a history of prior COVID-19 infection or detectable anti-SARS-CoV-2 nucleocapsid antibodies were included.

Exposures

Timing of the last vaccine dose and preterm or full-term gestational age at delivery.

Main Outcomes and Measures

Paired maternal and cord samples were tested for anti-S antibody, and linear regression was used to evaluate associations between preterm delivery and anti-S antibody levels. Covariates included timing of last dose, number of doses, insurance status, and immunosuppressing medications.

Results

A total of 220 participants (median [IQR] age, 34 [32-37] years; 212 [96.4%] female) with 36 preterm and 184 full-term deliveries were studied. Before delivery, 121 persons received 2 vaccine doses and 99 persons received 3 or more vaccine doses. The geometric mean concentration of maternal anti-S antibodies was 674 (95% CI, 577-787) after 2 doses and 8159 (95% CI, 6636-10 032) after 3 or more doses (P < .001). The cord anti-S antibody geometric mean concentration was 1000 (95% CI, 874-1144) after 2 doses and 9992 (95% CI, 8381-11 914) after 3 or more doses (P < .001). After adjustment for vaccine timing and number of doses before delivery, no association was found between preterm delivery and cord anti-S antibody levels (β = 0.44; 95% CI, -0.06 to 0.94).

Conclusions and Relevance

In this prospective cohort study of pregnant individuals with preterm and full-term deliveries, receipt of 3 or more compared with 2 doses of COVID-19 vaccine before delivery resulted in 10-fold higher cord anti-S antibody levels. Maternal antibody concentration appeared more important than delivery gestational age in determining cord anti-S antibody levels. The number of doses and timing considerations for COVID-19 vaccine in pregnancy should include individuals at risk for preterm delivery.

Biodistribution of RNA Vaccines and of Their Products: Evidence from Human and Animal Studies

Explosive developments in mRNA vaccine technology in the last decade have made it possible to achieve great success in clinical trials of mRNA vaccines to prevent infectious diseases and develop cancer treatments and mRNA-based gene therapy products. The approval of the mRNA-1273 and BNT162b2 mRNA vaccines against SARS-CoV-2 by the U.S. Food and Drug Administration has led to mass vaccination (with mRNA vaccines) of several hundred million people around the world, including children. Despite its effectiveness in the fight against COVID-19, rare adverse effects of the vaccination have been shown in some studies, including vascular microcirculation disorders and autoimmune and allergic reactions. The biodistribution of mRNA vaccines remains one of the most poorly investigated topics. This mini-review discussed the results of recent experimental studies on humans and rodents regarding the biodistribution of mRNA vaccines, their constituents (mRNA and lipid nanoparticles), and their encoded antigens. We focused on the dynamics of the biodistribution of mRNA vaccine products and on the possibility of crossing the blood-brain and blood-placental barriers as well as transmission to infants through breast milk. In addition, we critically assessed the strengths and weaknesses of the detection methods that have been applied in these articles, whose results' reliability is becoming a subject of debate.

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.

COVID-19 vaccine eligibility of pregnant and lactating women in Bangladesh: Gap between policy and policy interpretation among policymakers and healthcare workers

SARS-CoV-2 infection in pregnancy is associated with a greater risk of maternal and newborn morbidity and maternal death. Bangladesh confirmed its first COVID-19 case in March of 2020, and vaccination rollout started in January of 2021. In Bangladesh, pregnant women are allowed to receive COVID-19 vaccines during pregnancy with qualifications while lactating women are permitted to receive COVID-19 vaccines with no qualifications as of October 2021. There is limited evidence on how vaccine policies are disseminated, interpreted, and implemented from the national level to the community level in Bangladesh. We conducted in-depth interviews from April-August 2022 with policymakers and healthcare workers in Bangladesh to understand how different stakeholders understood and implemented COVID-19 vaccination policies related to pregnant and lactating women. We interviewed policymakers at three levels: national, divisional, and district, and interviewed healthcare workers from one one urban and three rural communities within one division. We found a gap between policies related to COVID-19 vaccination for pregnant and lactating women and policy interpretation among policymakers and healthcare workers. Policymakers and healthcare workers' perceptions differed related to policy dissemination, attitudes toward policies related to pregnant and lactating women, and eligibility of pregnant and lactating women. Our findings indicate the need for effective dissemination of and understanding of policies. Within the context of vaccine uptake and vaccine acceptance, policymakers play a critical role as they are charged with developing and disseminating policy related to vaccine eligibility. Healthcare workers rely on timely and accurate communication related to vaccine eligibility, including populations, timing, and locations. Efforts are needed to narrow the policy and policy implementation gap as doing so is crucial to controlling vaccine preventable disease.

Vaccination effects on reducing COVID-19 complications in pregnancy: A large-scale report from Iran

OBJECTIVE

The objective of this study was to evaluate the effects of maternal coronavirus disease 2019 (COVID-19) vaccination on preventing severe complications of COVID-19 in pregnant women.

METHODS

A retrospective study was conducted in pregnant women infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during pregnancy and/or for up to 6 weeks postpartum between September 1, 2021, to January 30, 2022. The data was retrieved from a national database. The pregnant women were divided into two groups of vaccinated and unvaccinated. The proposed outcomes (the need for hospitalization, intensive care unit admission, and mechanical ventilation and products of conception complications) were compared between the two groups.

RESULTS

Approximately 90 000 pregnant women infected with COVID-19 were included in the study. The data of the vaccinated (19 922) and unvaccinated (70 147) groups were analyzed and compared. Pregnant patients in the vaccinated group had a significantly lower rate of hospitalization (21.2% vs 29.4%) (odds ratio [OR], 0.648 [95% confidence interval (CI), 0.625-0.673], P = 0.0001) and intensive care unit admission (3.7% vs 7.8%) (OR, 0.453 [95% CI, 0.382-0.535], P = 0.0001). The need for mechanical ventilation was also lower, although not statistically significant, in the vaccinated group than in the unvaccinated group (30 of 155 [19.4%] vs 418 of 1597 [26.2%]) (OR, 0.677 [95% CI, 0.448-1.024], P = 0.063). Cesarean section (54.3% vs 58.1%) (OR, 0.856 [95% CI, 0.751-0.977], P = 0.021) and stillbirth (0.4% vs 3.6%) (OR, 0.097 [95% CI, 0.026-0.252], P = 0.0001) were also significantly lower in the vaccinated patients. Most pregnant women in the vaccinated group (18 484-96.14%) received Sinopharm BIBP COVID-19 inactivated vaccine. No significant differences were seen in the effect of different types of COVID-19 vaccines on reducing COVID-19 complications in infected pregnant patients.

CONCLUSION

Maternal COVID-19 immunization is effective in reducing COVID-19 complications in infected pregnant women.

Navigation of Knowledge: the Impact of COVID-19 on Pregnancy-a Bibliometric Analysis

Since the outbreak of COVID-19, countries around the world have faced huge economic and social burdens. SARS-COV-2 may exist in nature for a long time due to the diversity of its different variants. Pregnant women and newborns as vulnerable groups will suffer serious health threats. Bibliometrics as a method of summarizing publications can be used to extract important achievements and hot topics in this field. We search the target publications from the Web of Science Core collection database, and then use Microsoft Office Excel, CiteSpace, R, Scimago, and VOSviewer for visual analysis. Finally, we included 1709 publications from 2998 institutions in 104 countries. The number of publications has exploded since the COVID-19 pandemic in 2019. Among them, the USA, China, Britain, and Italy have higher quantity and quality. We identified important journals, authors, keywords, and references in this field. Anxiety, stress, risk of pregnancy complications, and vaccine safety and acceptance have received extensive attention from scholars during the COVID-19 pandemic and will continue to be urgent issues to be addressed in the future. Most of the current studies fall into the category of case reports and clinical data analysis. COVID-19 has been linked to serious pregnancy complications and mental illness, and vaccination during pregnancy is recommended to protect both mother and fetus. Further large-scale cohort studies and discovery of molecular mechanisms are needed in this field.

Factors associated with COVID-19 vaccination among pregnant women in Rio De Janeiro City, Brazil

COVID-19 vaccination during pregnancy is safe and effective in reducing the risk of complications. However, the uptake is still below targets worldwide. This study aimed to explore the factors associated with COVID-19 vaccination uptake among pregnant women since data on this topic is scarce in low-to-middle-income countries. A retrospective cohort study included linked data on COVID-19 vaccination and pregnant women who delivered a singleton live birth from August 1, 2021, to July 31, 2022, in Rio de Janeiro City, Brazil. Multiple logistic regression was performed to identify factors associated with vaccination during pregnancy, applying a hierarchical model and describing odds ratio with 95% confidence intervals. Of 65,304 pregnant women included in the study, 53.0% (95% CI, 52-53%) received at least one dose of COVID-19 vaccine during pregnancy. Higher uptake was observed among women aged older than 34 (aOR 1.21, 95%CI 1.15-1.28), black (aOR 1.10, 1.04-1.16), or parda/brown skin colour (aOR 1.05, 1.01-1.09), with less than eight years of education (aOR 1.09, 1.02-1.17), living without a partner (aOR 2.24, 2.16-2.34), more than six antenatal care appointments (aOR 1.92, 1.75-2.09), and having a previous child loss (OR 1.06, 1.02-1.11). These results highlight the need for targeted educational campaigns, trustful communication, and accessibility strategies for specific populations to improve vaccination uptake during pregnancy.

Effectiveness of a Messenger RNA Vaccine Booster Dose Against Coronavirus Disease 2019 Among US Healthcare Personnel, October 2021-July 2022

Background

Protection against symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (coronavirus disease 2019 [COVID-19]) can limit transmission and the risk of post-COVID conditions, and is particularly important among healthcare personnel. However, lower vaccine effectiveness (VE) has been reported since predominance of the Omicron SARS-CoV-2 variant.

Methods

We evaluated the VE of a monovalent messenger RNA (mRNA) booster dose against COVID-19 from October 2021 to June 2022 among US healthcare personnel. After matching case-participants with COVID-19 to control-participants by 2-week period and site, we used conditional logistic regression to estimate the VE of a booster dose compared with completing only 2 mRNA doses >150 days previously, adjusted for multiple covariates.

Results

Among 3279 case-participants and 3998 control-participants who had completed 2 mRNA doses, we estimated that the VE of a booster dose against COVID-19 declined from 86% (95% confidence interval, 81%-90%) during Delta predominance to 65% (58%-70%) during Omicron predominance. During Omicron predominance, VE declined from 73% (95% confidence interval, 67%-79%) 14-60 days after the booster dose, to 32% (4%-52%) ≥120 days after a booster dose. We found that VE was similar by age group, presence of underlying health conditions, and pregnancy status on the test date, as well as among immunocompromised participants.

Conclusions

A booster dose conferred substantial protection against COVID-19 among healthcare personnel. However, VE was lower during Omicron predominance, and waning effectiveness was observed 4 months after booster dose receipt during this period. Our findings support recommendations to stay up to date on recommended doses of COVID-19 vaccines for all those eligible.

International Pediatric COVID-19 Severity Over the Course of the Pandemic

Importance

Multiple SARS-CoV-2 variants have emerged over the COVID-19 pandemic. The implications for COVID-19 severity in children worldwide are unclear.

Objective

To determine whether the dominant circulating SARS-CoV-2 variants of concern (VOCs) were associated with differences in COVID-19 severity among hospitalized children.

Design, Setting, and Participants

Clinical data from hospitalized children and adolescents (younger than 18 years) who were SARS-CoV-2 positive were obtained from 9 countries (Australia, Brazil, Italy, Portugal, South Africa, Switzerland, Thailand, UK, and the US) during 3 different time frames. Time frames 1 (T1), 2 (T2), and 3 (T3) were defined to represent periods of dominance by the ancestral virus, pre-Omicron VOCs, and Omicron, respectively. Age groups for analysis were younger than 6 months, 6 months to younger than 5 years, and 5 to younger than 18 years. Children with an incidental positive test result for SARS-CoV-2 were excluded.

Exposures

SARS-CoV-2 hospitalization during the stipulated time frame.

Main Outcomes and Measures

The severity of disease was assessed by admission to intensive care unit (ICU), the need for ventilatory support, or oxygen therapy.

Results

Among 31 785 hospitalized children and adolescents, the median age was 4 (IQR 1-12) years and 16 639 were male (52.3%). In children younger than 5 years, across successive SARS-CoV-2 waves, there was a reduction in ICU admission (T3 vs T1: risk ratio [RR], 0.56; 95% CI, 0.42-0.75 [younger than 6 months]; RR, 0.61, 95% CI; 0.47-0.79 [6 months to younger than 5 years]), but not ventilatory support or oxygen therapy. In contrast, ICU admission (T3 vs T1: RR, 0.39, 95% CI, 0.32-0.48), ventilatory support (T3 vs T1: RR, 0.37; 95% CI, 0.27-0.51), and oxygen therapy (T3 vs T1: RR, 0.47; 95% CI, 0.32-0.70) decreased across SARS-CoV-2 waves in children 5 years to younger than 18 years old. The results were consistent when data were restricted to unvaccinated children.

Conclusions and Relevance

This study provides valuable insights into the impact of SARS-CoV-2 VOCs on the severity of COVID-19 in hospitalized children across different age groups and countries, suggesting that while ICU admissions decreased across the pandemic in all age groups, ventilatory and oxygen support generally did not decrease over time in children aged younger than 5 years. These findings highlight the importance of considering different pediatric age groups when assessing disease severity in COVID-19.

Maternal antibody transfer rate of vaccination against SARS-CoV-2 before or during early pregnancy and its protective effectiveness on offspring

This study focuses on maternal antibody transfer following vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) before or during early pregnancy and its potential protective effects on infants, providing scientific evidence for vaccination strategies. This prospective study tested the samples for SARS-CoV-2 IgG antibody titers and neutralizing capacity and tracked the infections after birth. Perform multivariate analysis of factors influencing antibody transfer rate, newborn antibody titers, and infant infection. Total 87.1% (122/140) women received coronavirus disease 2019 (COVID-19) vaccine before or during early pregnancy, and 28 of them had breakthrough infection. The maternal and neonatal IgG positive rates at delivery were 60.7% (85/140) and 60.8% (87/143), respectively. A positive correlation was found between neonatal and maternal IgG antibody titers. Compared with the median IgG antibody transfer rate of infected pregnant women, that of vaccinated but not infected pregnant women was higher (1.21 versus: 1.53 [two doses], 1.71 [three doses]). However, neonatal IgG antibodies were relatively low (174.91 versus: 0.99 [two doses], 8.18 [three doses]), and their neutralizing capacity was weak. The overall effectiveness of maternal vaccination in preventing infant infection was 27.0%, and three doses had higher effectiveness than two doses (64.3% vs. 19.6%). Multivariate analysises showed that in vaccination group women receiving three doses or in infection group women with longer interval between infection and delivery had a higher antibody transfer rate and neonatal IgG antibody titer. More than half of women vaccinated before or during early pregnancy can achieve effective antibody transfer to newborns. However, the neonatal IgG antibody titer is low and has a weak neutralizing capacity, providing limited protection to infants.

Are maternal vaccines effective and safe for mothers and infants? A systematic review and meta-analysis of randomised controlled trials

INTRODUCTION

Maternal vaccination is a promising strategy to reduce the burden of vaccine-preventable diseases for mothers and infants. We aimed to provide an up-to-date overview of the efficacy and safety of all available maternal vaccines.

METHODS

We searched PubMed, Embase, CENTRAL and ClinicalTrials.gov on 1 February 2022, for phase III and IV randomised controlled trials (RCTs) that compared maternal vaccination against any pathogen with placebo or no vaccination. Primary outcomes were laboratory-confirmed or clinically confirmed disease in mothers and infants. Secondary safety outcomes included intrauterine growth restriction, stillbirth, maternal death, preterm birth, congenital malformations and infant death. Random effects meta-analysis were used to calculate pooled risk ratio's (RR). Quality appraisal was performed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE).

RESULTS

Six RCTs on four maternal vaccines, influenza, tetanus, diphtheria and pertussis (Tdap), pneumococcal and respiratory syncytial virus (RSV) were eligible. The overall risk of bias and certainty of evidence varied from low to high. Maternal influenza vaccination significantly reduced the number of laboratory-confirmed influenza cases (RR 0.58, 95% CI 0.42 to 0.79, event rate 57 vs 98, 2 RCTs, n=6003, I2=0%), and clinically confirmed influenza cases in mothers (RR 0.88, 95% CI 0.78 to 0.99, event rate 418 vs 472, 2 RCTs, n=6003, I2=0%), and laboratory-confirmed influenza in infants (RR 0.66, 95% CI 0.52 to 0.85, event rate 98 vs 148, 2 RCTs, n=5883, I2=0%), although this was not significant for clinically confirmed influenza in infants (RR 0.99, 95% CI 0.94 to 1.05, event rate 1371 vs 1378, 2 RCTs, n=5883, I2=0%). No efficacy data were available on maternal Tdap vaccination. Maternal pneumococcal vaccination did not reduce laboratory-confirmed and clinically confirmed middle ear disease (RR 0.49, 95% CI 0.24 to 1.02, event rate 9 vs 18, 1 RCT, n=133 and RR 0.88 95% CI 0.69 to 1.12, event rate 42 vs 47, 1 RCT, n=133, respectively), and clinically confirmed lower-respiratory tract infection (LRTI) (RR 1.08, 95% CI 0.82 to 1.43, event rate 18 vs 34, 1 RCT, n=70) in infants. Maternal RSV vaccination did not reduce laboratory-confirmed RSV LRTI in infants (RR 0.75, 95% CI 0.56 to 1.01, event rate 103 vs 71, 1 RCT, n=4527). There was no evidence of a significant effect of any of the maternal vaccines on the reported safety outcomes.

CONCLUSIONS

The few RCTs with low event rates suggest that, depending on the type of maternal vaccine, the vaccine might effectively prevent disease and within its size does not show safety concerns in mothers and infants.

PROSPERO REGISTRATION NUMBER

CRD42021235115.

mRNA vaccines against respiratory viruses

PURPOSE OF REVIEW

The successes of the coronavirus disease 2019 (COVID-19) mRNA vaccines have accelerated the development of mRNA vaccines against other respiratory pathogens. The aim of this review is to highlight COVID-19 mRNA vaccine advances and provide an update on the progress of mRNA vaccine development against other respiratory pathogens.

RECENT FINDINGS

The COVID-19 mRNA vaccines demonstrated effectiveness in preventing severe COVID-19 and death. H7N9 and H10N8 avian influenza mRNA vaccines have demonstrated safety and immunogenicity in phase 1 clinical trials. Numerous seasonal influenza mRNA vaccines are in phase 1-3 clinical trials. Respiratory syncytial virus (RSV) mRNA vaccines have progressed to phase 2-3 clinical trials in adults and a phase 1 clinical trial in children. A combined human metapneumovirus and parainfluenza-3 mRNA vaccines was found to be well tolerated and immunogenic in a phase 1 trial among adults and trials are being conducted among children. Clinical trials of mRNA vaccines combining antigens from multiple respiratory viruses are underway.

SUMMARY

The development of mRNA vaccines against respiratory viruses has progressed rapidly in recent years. Promising vaccine candidates are moving through the clinical development pathway to test their efficacy in preventing disease against respiratory viral pathogens.

Effectiveness of Maternal mRNA COVID-19 Vaccination During Pregnancy Against COVID-19-Associated Hospitalizations in Infants Aged <6 Months During SARS-CoV-2 Omicron Predominance - 20 States, March 9, 2022-May 31, 2023

Infants aged <6 months are not eligible for COVID-19 vaccination. Vaccination during pregnancy has been associated with protection against infant COVID-19-related hospitalization. The Overcoming COVID-19 Network conducted a case-control study during March 9, 2022-May 31, 2023, to evaluate the effectiveness of maternal receipt of a COVID-19 vaccine dose (vaccine effectiveness [VE]) during pregnancy against COVID-19-related hospitalization in infants aged <6 months and a subset of infants aged <3 months. VE was calculated as (1 - adjusted odds ratio) x 100% among all infants aged <6 months and <3 months. Case-patients (infants hospitalized for COVID-19 outside of birth hospitalization and who had a positive SARS-CoV-2 test result) and control patients (infants hospitalized for COVID-19-like illness with a negative SARS-CoV-2 test result) were compared. Odds ratios were determined using multivariable logistic regression, comparing the odds of receipt of a maternal COVID-19 vaccine dose (completion of a 2-dose vaccination series or a third or higher dose) during pregnancy with maternal nonvaccination between case- and control patients. VE of maternal vaccination during pregnancy against COVID-19-related hospitalization was 35% (95% CI = 15%-51%) among infants aged <6 months and 54% (95% CI = 32%-68%) among infants aged <3 months. Intensive care unit admissions occurred in 23% of all case-patients, and invasive mechanical ventilation was more common among infants of unvaccinated (9%) compared with vaccinated mothers (1%) (p = 0.02). Maternal vaccination during pregnancy provides some protection against COVID-19-related hospitalizations among infants, particularly those aged <3 months. Expectant mothers should remain current with COVID-19 vaccination to protect themselves and their infants from hospitalization and severe outcomes associated with COVID-19.

Antibody attributes, Fc receptor expression, gestation and maternal SARS-CoV-2 infection modulate HSV IgG placental transfer

Antibody-dependent cellular cytotoxicity (ADCC) is associated with protection against neonatal herpes. We hypothesized that placental transfer of ADCC-mediating herpes simplex virus (HSV) immunoglobulin G (IgG) is influenced by antigenic target, function, glycans, gestational age, and maternal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Maternal and cord blood were collected from HSV-seropositive (HSV+) mothers pre-COVID and HSV+/SARS-CoV-2+ mothers during the pandemic. Transfer of HSV neutralizing IgG was significantly lower in preterm versus term dyads (transfer ratio [TR] 0.84 vs. 2.44) whereas the TR of ADCC-mediating IgG was <1.0 in both term and preterm pre-COVID dyads. Anti-glycoprotein D IgG, which had only neutralizing activity, and anti-glycoprotein B (gB) IgG, which displayed neutralizing and ADCC activity, exhibited different relative affinities for the neonatal Fc receptor (FcRn) and expressed different glycans. The transfer of ADCC-mediating IgG increased significantly in term SARS-CoV-2+ dyads. This was associated with greater placental colocalization of FcRn with FcγRIIIa. These findings have implications for strategies to prevent neonatal herpes.

Minimal mRNA uptake and inflammatory response to COVID-19 mRNA vaccine exposure in human placental explants

Despite universal recommendations for COVID-19 mRNA vaccination in pregnancy, uptake has been lower than desired. There have been limited studies of the direct impact of COVID-19 mRNA vaccine exposure in human placental tissue. Using a primary human placental explants model, we investigated the uptake of two common mRNA vaccines (BNT162b2 Pfizer-BioNTech or mRNA-1273 Moderna), and whether exposure altered villous cytokine responses. Explants derived from second or third trimester chorionic villi were incubated with vaccines at supraphysiologic concentrations and analyzed at two time points. We observed minimal uptake of mRNA vaccines in placental explants by in situ hybridization and quantitative RT-PCR. No specific or global cytokine response was elicited by either of the mRNA vaccines in multiplexed immunoassays. Our results suggest that the human placenta does not readily absorb the COVID-19 mRNA vaccines nor generate a significant inflammatory response after exposure.

Clinical outcomes of COVID-19 and influenza in hospitalized children <5 years in the US

Introduction

We compared hospitalization outcomes of young children hospitalized with COVID-19 to those hospitalized with influenza in the United States.

Methods

Patients aged 0-<5 years hospitalized with an admission diagnosis of acute COVID-19 (April 2021-March 2022) or influenza (April 2019-March 2020) were selected from the PINC AI Healthcare Database Special Release. Hospitalization outcomes included length of stay (LOS), intensive care unit (ICU) admission, oxygen supplementation, and mechanical ventilation (MV). Inverse probability of treatment weighting was used to adjust for confounders in logistic regression analyses.

Results

Among children hospitalized with COVID-19 (n = 4,839; median age: 0 years), 21.3% had an ICU admission, 19.6% received oxygen supplementation, 7.9% received MV support, and 0.5% died. Among children hospitalized with influenza (n = 4,349; median age: 1 year), 17.4% were admitted to the ICU, 26.7% received oxygen supplementation, 7.6% received MV support, and 0.3% died. Compared to children hospitalized with influenza, those with COVID-19 were more likely to have an ICU admission (adjusted odds ratio [aOR]: 1.34; 95% confidence interval [CI]: 1.21-1.48). However, children with COVID-19 were less likely to receive oxygen supplementation (aOR: 0.71; 95% CI: 0.64-0.78), have a prolonged LOS (aOR: 0.81; 95% CI: 0.75-0.88), or a prolonged ICU stay (aOR: 0.56; 95% CI: 0.46-0.68). The likelihood of receiving MV was similar (aOR: 0.94; 95% CI: 0.81, 1.1).

Conclusions

Hospitalized children with either SARS-CoV-2 or influenza had severe complications including ICU admission and oxygen supplementation. Nearly 10% received MV support. Both SARS-CoV-2 and influenza have the potential to cause severe illness in young children.

Using the COM-B framework to elucidate facilitators and barriers to COVID-19 vaccine uptake in pregnant women: a qualitative study

Since April 2021, COVID-19 vaccines have been recommended for pregnant women. Despite this, COVID-19 vaccine uptake in this group is low compared to the non-pregnant population of childbearing age. Our aim was to understand barriers and facilitators to COVID-19 vaccine uptake among pregnant women in Northern Ireland using the COM-B framework, and so to make recommendations for public health interventions. The COM-B proposes that human behaviour is influenced by the extent to which a person has the capability, opportunity, and motivation to enact that behaviour. Understanding the factors underpinning behaviour through this lens helps discern what needs to change to change behaviour, therefore supporting the development of targeted interventions.This study consisted of eight semi-structured interviews with new/expectant mothers who did not receive a COVID-19 vaccine dose while pregnant since April 2021, and a focus group with five participants who received at least one COVID-19 vaccine dose while pregnant. Interview and focus group data were analysed using semi-deductive reflexive thematic analysis framed by a subtle realist approach. The COM-B was used to categorise codes and subthemes were developed within each COM-B construct.Within Psychological Capability, subthemes captured the need for consistent and reliable COVID-19 vaccine information and access to balanced and jargon-free, risk-benefit information that is tailored to the pregnant individual. The behaviour/opinions of family, friends, and local healthcare providers had a powerful influence on COVID-19 vaccine decisions (Social Opportunity). Integrating the COVID-19 vaccine as part of routine antenatal pathways was believed to support access and sense of familiarity (Physical Opportunity). Participants valued health autonomy, however experienced internal conflict driven by concerns about long-term side effects for their baby (Reflective Motivation). Feelings of fear, lack of empathy from healthcare providers, and anticipated guilt commonly underpinned indecision as to whether to get the vaccine (Automatic Motivation).Our study highlighted that the choice to accept a vaccine during pregnancy generates internal conflict and worry. Several participants cited their concern was primarily around the safety for their baby. Healthcare professionals (HCPs) play a significant part when it comes to decision making about COVID-19 vaccines among pregnant women. HCPs and pregnant women should be involved in the development of interventions to improve the delivery and communication of information.

Effect of COVID-19 vaccination and booster on maternal-fetal outcomes: a retrospective cohort study

BACKGROUND

COVID-19 in pregnant people increases the risk for poor maternal-fetal outcomes. However, COVID-19 vaccination hesitancy remains due to concerns over the vaccine's potential effects on maternal-fetal outcomes. Here we examine the impact of COVID-19 vaccination and boosters on maternal SARS-CoV-2 infections and birth outcomes.

METHODS

This was a retrospective multicentre cohort study on the impact of COVID-19 vaccination on maternal-fetal outcomes for people who delivered (n=106 428) at Providence St Joseph Health across seven western US states from Jan 26, 2021 to Oct 26, 2022. Cohorts were defined by vaccination status at delivery: vaccinated (n=35 926; two or more doses of mRNA-1273 Moderna or BNT162b2 Pfizer-BioNTech), unvaccinated (n=55 878), unvaccinated propensity score matched (n=16 771), boosted (n=10 927; three or more doses), vaccinated unboosted (n=13 243; two doses only), and vaccinated unboosted with propensity score matching (n=4414). We built supervised machine learning classification models, which we used to determine which people were more likely to be vaccinated or boosted at delivery. The primary outcome was maternal SARS-CoV-2 infection. COVID-19 vaccination status at delivery, COVID-19-related health care, preterm birth, stillbirth, and very low birthweight were evaluated as secondary outcomes.

FINDINGS

Vaccinated people were more likely to conceive later in the pandemic, have commercial insurance, be older, live in areas with lower household composition vulnerability, and have a higher BMI than unvaccinated people. Boosted people were more likely to have more days since receiving the second COVID-19 vaccine dose, conceive earlier in the pandemic, have commercial insurance, be older, and live in areas with lower household composition vulnerability than vaccinated unboosted people. Vaccinated pregnant people had lower rates of COVID-19 during pregnancy (4·0%) compared with unvaccinated matched people (5·3%; p<0·0001). COVID-19 rates were even lower in boosted people (3·2%) compared with vaccinated unboosted matched people (5·6%; p<0·0001). Vaccinated people were also less likely to have a preterm birth (7·9%; p<0·0001), stillbirth (0·3%; p<0·0002), or very low birthweight neonate (1·0%; p<0·0001) compared with unvaccinated matched people (preterm birth 9·4%; stillbirth 0·6%; very low birthweight 1·5%). Boosted people were less likely to have a stillbirth (0·3%; p<0·025) and have no differences in rates of preterm birth (7·6%; p=0·090) or very low birthweight neonates (0·8%; p=0·092) compared with vaccinated unboosted matched people (stillbirth 0·5%; preterm birth 8·4%; very low birthweight 1·1%).

INTERPRETATION

COVID-19 vaccination protects against adverse maternal-fetal outcomes, with booster doses conferring additional protection. Pregnant people should be high priority for vaccination and stay up to date with their COVID-19 vaccination schedule.

FUNDING

National Institute for Child Health & Human Development and the William O and K Carole Ellison Foundation.

Dilemmas and options for COVID-19 vaccination in children

Over 16 million children have been detected positive for the coronavirus disease 2019 (COVID-19) in the United States since the outbreak of the pandemic. In general, children infected with severe acute respiratory syndrome coronavirus type 2 tend to have lighter symptoms than adults. However, in some cases, the infection can develop into severe forms, such as multisystem inflammatory syndrome in children. Moreover, long-term public health preventive interventions have had some negative effects on the physical and mental health of children. Given the important role that vaccination plays in reducing severe illness and mortality, it is essential for the efficient implementation of vaccination in the pediatric population. Nevertheless, parental distrust of vaccination, especially with regard to its safety and efficacy, hinders this process. Herein, we comprehensively summarize the available data on the safety and effectiveness of COVID-19 vaccine in children. The results show that the currently approved COVID-19 vaccine is safe and effective for children. Although two doses of vaccine in children seem insufficient to prevent Omicron infection, the booster dose provides enhanced protection against infection and severe illness. Most importantly, the bivalent vaccine has been approved for use in the pediatric population to extend the immune response to currently circulating Omicron variant. And the immune protection afforded to newborns after maternal vaccination appears to last only 6 months. Therefore, in the current situation where the rate of virus mutation is accelerating and the COVID-19 pandemic is still severe, it is crucial to extend vaccine protection to children over 6 months of age to weave a tighter safety net.

Effectiveness of Maternal Inactivated COVID-19 Vaccination against Omicron Infection in Infants during the First 12 Months of Life: A Test-Negative Case-Control Study

This study aims to evaluate the effectiveness of maternal inactivated COVID-19 vaccination before delivery for infants against Omicron infection in Guangzhou, China. A test-negative case-control design was conducted. This study selected infants born from 1 November 2021 to 23 November 2022 and tested for SARS-CoV-2 between 13 April 2022 and 30 November 2022 during outbreaks in Guangzhou. Multivariable logistic regression was performed to compare the maternal vaccination status of inactivated COVID-19 vaccines before delivery in cases and controls to estimate vaccine effectiveness (VE) for infants within 12 months. According to eligibility criteria, we finally selected 205 test-positive and 114 test-negative infants, as well as their mothers. The effectiveness of inactivated COVID-19 vaccines among fully vaccinated mothers was 48.4% (7.3% to 71.7%) for infants within 12 months, with the effectiveness of partial and booster vaccination showing no significant difference. Effectiveness for full vaccination presented a slight increase according to infants' age at testing, with 49.6% (-12.3% to 78.4%) for 0-6 months and 59.9% (-0.6% to 84.4%) for over 6 months. A greater protective effect of two-dose vaccination was manifested in infants whose mother had received the second dose during the first trimester (65.9%, 95% CI: 7.7% to 87.9%) of pregnancy rather than preconception (43.5%, 95% CI: -8.7% to 71.1%). Moreover, VE could be improved to 77.1% (11.1% to 95.3%) when mothers received two doses both during pregnancy and 91.8% (41.1% to 99.6%) with receipt of a booster dose during pregnancy. Maternal vaccination with two doses of inactivated COVID-19 vaccines before delivery was moderately effective against Omicron infection in infants during the first 12 months of life. Full vaccination or a booster dose during pregnancy could confer better protection against Omicron for infants, although it might be overestimated due to the insufficient sample size in subgroups.

SARS-CoV-2 vaccination, booster, and infection in pregnant population enhances passive immunity in neonates

The effects of heterogeneous infection, vaccination and boosting histories prior to and during pregnancy have not been extensively studied and are likely important for protection of neonates. We measure levels of spike binding antibodies in 4600 patients and their neonates with different vaccination statuses, with and without history of SARS-CoV-2 infection. We investigate neutralizing antibody activity against different SARS-CoV-2 variant pseudotypes in a subset of 259 patients and determined correlation between IgG levels and variant neutralizing activity. We further study the ability of maternal antibody and neutralizing measurements to predict neutralizing antibody activity in the umbilical cord blood of neonates. In this work, we show SARS-CoV-2 vaccination and boosting, especially in the setting of previous infection, leads to significant increases in antibody levels and neutralizing activity even against the recent omicron BA.1 and BA.5 variants in both pregnant patients and their neonates.

Pregnant women with mild COVID-19 followed in community setting by telemedicine, and factors associated with unfavorable outcome

OBJECTIVES

Few is known on pregnant women with mild COVID-19 managed in a community setting with a telemedicine solution, including their outcomes. The objective of this study is to evaluate the adverse fetal outcomes and hospitalization rates of pregnant COVID-19 outpatients who were monitored with the Covidom© telemedicine solution.

METHODS

A nested study was conducted on pregnant outpatients with confirmed COVID-19, who were managed with Covidom© between March and November 2020. The patients were required to complete a standard medical questionnaire on co-morbidities and symptoms at inclusion, and were then monitored daily for 30 days after symptom onset. Adverse fetal outcome was defined as a composite of preterm birth, low birthweight, or stillbirth, and was collected retrospectively through phone contact with a standardized questionnaire.

RESULTS

The study included 714 pregnant women, with a median age of 32.0 [29.0-35.0] and a median BMI of 23.8 [21.3-27.0]. The main comorbidities observed were smoking (53%), hypertension (19%). The most common symptoms were asthenia (45.6%), cough (40.3%) and headache (25.7%), as well as anosmia (28.4%) and agueusia (32.3%). Adverse fetal outcomes occurred in 64 (9%) cases, including 38 (5%) preterm births, 33 (5%) low birthweights, and 6 (1%) stillbirths. Hospitalization occurred in 102 (14%) cases and was associated with adverse fetal outcomes (OR 2.4, 95% CI 1.3-4.4).

CONCLUSIONS

Our study suggests that adverse fetal outcomes are rare in pregnant women with mild COVID-19 who are monitored at home with telemedicine. However, hospitalization for COVID-19 and pregnancy-induced hypertension are associated with a higher risk of adverse fetal outcome.

Immunogenicity and reactogenicity of heterologous COVID-19 vaccination in pregnant women

This open-labeled non-inferiority trial evaluated immunogenicity and reactogenicity of heterologous and homologous COVID-19 vaccination schedules in pregnant Thai women. 18-45-year-old pregnant women with no history of COVID-19 infection or vaccination and a gestational age of ≥12 weeks were randomized 1:1:1 into three two-dose primary series scheduled 4 weeks apart: BNT162b2-BNT162b2 (Group 1), ChAdOx1-BNT162b2 (Group 2), and CoronaVac-BNT162b2 (Group 3). Serum antibody responses, maternal and cord blood antibody levels at delivery, and adverse events (AEs) following vaccination until delivery were assessed. The 124 enrolled participants had a median age of 31 (interquartile range [IQR] 26.0-35.5) years and gestational age of 23.5 (IQR 18.0-30.0) weeks. No significant difference in anti-receptor binding domain (RBD) IgG were observed across arms at 2 weeks after the second dose. Neutralizing antibody geometric mean titers against the ancestral Wuhan strain were highest in Group 3 (258.22, 95% CI [187.53, 355.56]), followed by Groups 1 (187.47, 95% CI [135.15, 260.03]) and 2 (166.63, 95% CI [124.60, 222.84]). Cord blood anti-RBD IgG was correlated with, and equal to or higher than, maternal levels at delivery (r = 0.719, P < .001) and inversely correlated with elapsed time after the second vaccination (r = -0.366, P < .001). No significant difference in cord blood antibody levels between groups were observed. Local and systemic AEs were mild-to-moderate and more frequent in Group 2. Heterologous schedules of CoronaVac-BNT162b2 or ChAdOx1-BNT162b2 induced immunogenicity on-par with BNT162b2-BNT162b2 and may be considered as alternative schedules for primary series in pregnant women in mRNA-limited vaccine settings.