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

Neonatal SARS-CoV-2 mRNA Vaccination Efficacy Is Influenced by Maternal Antibodies

PROBLEM

Vaccination in pregnancy guards against infection. Maternal antibodies, however, can inhibit antibody production in neonates. We sought to determine the effects of maternal vaccination on neonatal immune response to a SARS-CoV-2 mRNA vaccine.

METHOD OF STUDY

We hypothesized that mRNA-lipid nanoparticles (LNP) vaccination allows for a de novo neonatal antibody response even in the presence of vertically transmitted maternal antibodies. Female mice were vaccinated with SARS-CoV-2 spike receptor binding domain (RBD) mRNA-LNPs. Mice were then bred, and 21-day-old pups were inoculated with the same mRNA-LNPs. Spike-specific IgG ELISAs were performed using mouse serum. A SARS-CoV-2 spike protein peptide library to perform peptide ELISAs characterized high affinity binding domains within the spike protein. Results were analyzed with one-way ANOVAs with Tukey's multiple comparisons tests.

RESULTS

Compared to pups of unvaccinated dams, there were high levels of spike-specific IgG detected in the pups of vaccinated dams at 3 weeks of life (p < 0.0001). After neonatal vaccination, pups of unvaccinated dams had higher spike-specific serum IgG than pups of vaccinated dams at 12 weeks of life (p < 0.001). Antibody specificity to peptide moieties within spike RBD were similar when comparing a vaccinated dam to her pup at Week 3 of life, with different binding affinities observed in the pups by Week 15 of life.

CONCLUSIONS

Pre-existing maternal antibodies may partially blunt the initial neonatal antibody response to mRNA-LNPs vaccination. This vaccine strategy, however, does not prohibit the subsequent development of a broad range of RBD antibody specificities that may be protective.

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.

Effectiveness of the Original Monovalent and Bivalent COVID-19 Vaccines Against COVID-19-Associated Emergency Department and Urgent Care Encounters in Pregnant Persons Who Were Not Immunocompromised: VISION Network, June 2022-August 2023

Pregnant people face increased risk of severe COVID-19. Current guidelines recommend updated COVID-19 vaccination (2023-2024) for those aged ≥6 months, irrespective of pregnancy status. To refine recommendations for pregnant people, further data are needed. Using a test-negative design, we evaluated COVID-19 vaccine effectiveness against medically attended COVID-19 with COVID-19-like illness among pregnant people aged 18 to 45 years during June 2022 to August 2023. When doses were received during pregnancy, vaccine effectiveness was 52% (95% CI, 29%-67%); when received <6 months prior to pregnancy, 28% (95% CI, 11%-42%); and when received ≥6 months prior to pregnancy, 6% (95% CI, -11% to 21%). Pregnant people should stay up-to-date with recommended COVID-19 vaccination.

Pregnant individuals perspectives towards receiving COVID-19 vaccination during their pregnancy: an in-depth qualitative study

Introduction

Pregnant individuals have an increased risk of severe illness from coronavirus disease 2019 (COVID-19) infection. Vaccination is an effective strategy to prevent severe illness and complications for pregnant individuals. Pregnant individuals are often excluded from research and remain hesitant to receive vaccination against COVID-19. It is pivotal to study factors related to vaccine uptake and hesitancy among pregnant individuals. We studied barriers and facilitators for pregnant individuals choice and motivation regarding vaccination against COVID-19 during pregnancy to aid future pregnant individuals in their decision to vaccinate against various infectious agents.

Methods

In this qualitative study, pregnant individuals were interviewed between October 2021 and January 2022 using a semi-structured approach. A topic list was used to explore their feelings, perceptions and ideas regarding vaccination against COVID-19 during pregnancy. Interviews were transcribed verbatim and thematic analyses was performed using MAX QDA.

Results

After nine interviews, saturation was reached. Three main themes were identified that influenced pregnant individuals choice and motivation regarding vaccination: health consequences, ambiguity of information and societal motivation. Health consequences mainly concerned the effect for their offspring, and the unknown long-term effects of COVID-19 vaccination. The advice from the Dutch institute for Public Health and Environment changed from not vaccinating pregnant individuals after release of the developed vaccine, to routinely vaccinating all pregnant individuals after research data were available from the United States of America (USA). This change of policy fuelled doubt and confusion for vaccination. Arguments in favor of vaccination from the social perspective were specific behaviour rules and restrictions due to the pandemic. E.g. without vaccination people were unable to travel abroad and having to take a COVID-19 test every time entering a public place.

Conclusion

Pregnant individuals need clear, unambiguous information concerning health consequences, short- and long-term, particularly for their offspring, in the decision-making process regarding COVID-19 vaccination. Additionally, the societal perspective needs to be addressed. Besides the aforementioned themes, general counselling should focus on misperceptions of vaccine safety and the role of misinformation which are also important in the non-pregnant population. This study underlines the importance of including pregnant individuals in research programs to obtain specific information targeted to their needs.

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.

Newborns at risk of COVID-19, the story continues

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

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

Introduction

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

Methods

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

Results and discussion

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

Causes and Effects of COVID-19 Vaccine Hesitancy Among Pregnant Women and its Association with Adverse Maternal, Placental, and Perinatal Outcomes

Populations identified to be severely affected by COVID-19, such as pregnant patients, require special consideration in vaccine counseling, access, and provider education. Maternal infection with COVID-19 poses a significant risk to the maternal-fetal dyad with known adverse placenta destruction [1-5]. Despite the widespread access and availability of vaccinations, vaccine hesitancy continues to persist and is highly prevalent in pregnant populations [6-9]. Addressing the multitude of social ecological factors surrounding vaccine hesitancy can aid in providing holistic counseling [10]. However, such factors are foremost shaped by maternal concern over possible fetal effects from vaccination. While changes in policy can help foster vaccine access and acceptance, increasing global provider education and incorporation of motivational interviewing skills are the first steps towards increasing maternal acceptance.

Planning for the future of maternal immunization: Building on lessons learned from the COVID-19 pandemic

As the worldwide COVID-19 pandemic unfolded, the clinical and public health community raced to understand SARS-CoV-2 infection and develop life-saving vaccines. Pregnant persons were disproportionately impacted, experiencing more severe illness and adverse pregnancy outcomes. And yet, when COVID-19 vaccines became available in late 2020, safety and efficacy data were not available to inform their use during pregnancy because pregnant persons were excluded from pre-authorization clinical trials. Concerns about vaccine safety during pregnancy and misinformation linking vaccination and infertility circulated widely, creating a lack of vaccine confidence. Many pregnant people initially chose not to get vaccinated, and while vaccination rates rose after safety and effectiveness data became available, COVID-19 vaccine acceptance was suboptimal and varied across racial and ethnic distribution of the pregnant population. The COVID-19 pandemic experience provided valuable insights that can inform current and future approaches to maternal vaccination against.

Responses to Common Misconceptions Relating to COVID-19 Variant-Adapted mRNA Vaccines

The evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the waning of immunity over time has necessitated the use of booster doses of original coronavirus disease 2019 (COVID-19) vaccines. This has also led to the development and implementation of variant-adapted messenger RNA (mRNA) vaccines that include an Omicron sub-lineage component in addition to the antigen based on the wild-type virus spike protein. Subsequent emergence of the recombinant XBB sub-lineages triggered the development of monovalent XBB-based variant-adapted mRNA vaccines, which are available for vaccination campaigns in late 2023. Misconceptions about new variant-adapted vaccines may exacerbate vaccine fatigue and drive the lack of vaccine acceptance. This article aims to address common concerns about the development and use of COVID-19 variant-adapted mRNA vaccines that have emerged as SARS-CoV-2 has continued to evolve.