A scoping review of global COVID-19 vaccine hesitancy among pregnant persons.

Uptake of the COVID-19 vaccine among pregnant persons is lower than the general population. This scoping review explored pregnant people's attitudes towards the COVID-19 vaccine, reasons for vaccine hesitancy, and whether attitudes about COVID-19 vaccines differ by country of origin. A scoping review was conducted across PubMed, Embase, CINHAL, and Scopus. Inclusion criteria were articles published in English from 2019-2022 focused on attitudes towards COVID-19 vaccination among pregnant persons. Data analysis was done via the 5Cs framework for vaccine hesitancy: Constraints, Complacency, Calculation, Confidence, and Collective Responsibility. 44 articles were extracted. A lack of confidence in vaccine safety was the most prevalent theme of hesitancy among pregnant persons. This was largely driven by a lack of access to information about the vaccine as well as mistrust of the vaccine and medical professionals. Meanwhile, vaccine acceptance was mostly driven by a desire to protect themselves and their loved ones. Overall, COVID-19 vaccine hesitancy among pregnant persons continues to be high. Vaccine hesitancy is primarily driven by fear of the unknown side effects of the vaccine on pregnant persons and their fetuses along with a lack of information and medical mistrust. Some differences can be seen between high income and low- and middle-income countries regarding vaccine hesitancy, showing that a single solution cannot be applied to all who are vaccine hesitant. General strategies, however, can be utilized to reduce vaccine hesitancy, including advocating for inclusion of pregnant persons in clinical trials and incorporating consistent COVID-19 vaccine counseling during prenatal appointments.

Licensed H5N1 vaccines generate cross-neutralizing antibodies against highly pathogenic H5N1 clade 2.3.4.4b influenza virus.

The emergence of highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4b viruses and their transmission to dairy cattle and animals, including humans, poses a major global public health threat. Therefore, the development of effective vaccines and therapeutics against H5N1 clade 2.3.4.4b virus is considered a public health priority. In the United States, three H5N1 vaccines derived from earlier strains of HPAI H5N1 (A/Vietnam, clade 1, and A/Indonesia, clade 2.1) virus, with (MF59 or AS03) or without adjuvants, are licensed and stockpiled for pre-pandemic preparedness, but whether they can elicit neutralizing antibodies against circulating H5N1 clade 2.3.4.4b viruses is unknown. In this study, we evaluated the binding, hemagglutination inhibition and neutralizing antibody response generated after vaccination of adults with the three licensed vaccines. Individuals vaccinated with the two adjuvanted licensed H5N1 vaccines generated cross-reactive binding and cross-neutralizing antibodies against the HPAI clade 2.3.4.4b A/Astrakhan/3212/2020 virus. Seroconversion rates of 60-95% against H5 clade 2.3.4.4b were observed after two doses of AS03-adjuvanted-A/Indonesia or three doses of MF59-adjuvanted-A/Vietnam vaccine. These findings suggest that the stockpiled US-licensed adjuvanted H5N1 vaccines generate cross-neutralizing antibodies against circulating HPAI H5N1 clade 2.3.4.4b in humans and may be useful as bridging vaccines until updated H5N1 vaccines become available.

Monoclonal antibodies targeting sites in respiratory syncytial virus attachment G protein provide protection against RSV-A and RSV-B in mice.

Currently, only Palivizumab and Nirsevimab that target the respiratory syncytical virus (RSV) fusion protein are licensed for pre-treatment of infants. Glycoprotein-targeting antibodies may also provide protection against RSV. In this study, we generate monoclonal antibodies from mice immunized with G proteins from RSV-A2 and RSV-B1 strains. These monoclonal antibodies recognize six unique antigenic classes (G0-G5). None of the anti-G monoclonal antibodies neutralize RSV-A2 or RSV-B1 in vitro. In mice challenged with either RSV-A2 line 19 F or RSV-B1, one day after treatment with anti-G monoclonal antibodies, all monoclonal antibodies reduce lung pathology and significantly reduce lung infectious viral titers by more than 2 logs on day 5 post-RSV challenge. RSV dissemination in the lungs was variable and correlated with lung pathology. We demonstrate new cross-protective anti-G monoclonal antibodies targeting multiple sites including conformation-dependent class G0 MAb 77D2, CCD-specific class G1 MAb 40D8, and carboxy terminus of CCD class G5 MAb 7H11, to support development of G-targeting monoclonal antibodies against RSV.

Reduced control of SARS-CoV-2 infection associates with lower mucosal antibody responses in pregnancy.

Pregnant patients are at greater risk of hospitalization with severe COVID-19 than non-pregnant people. This was a retrospective observational cohort study of remnant clinical specimens from patients who visited acute care hospitals within the Johns Hopkins Health System in the Baltimore, MD-Washington DC, area between October 2020 and May 2022. Participants included confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected pregnant people and matched non-pregnant people (the matching criteria included age, race/ethnicity, area deprivation index, insurance status, and vaccination status to ensure matched demographics). The primary dependent measures were clinical COVID-19 outcomes, infectious virus recovery, viral RNA levels, and mucosal anti-spike (S) IgG titers from upper respiratory tract samples. A total of 452 individuals (117 pregnant and 335 non-pregnant) were included in the study, with both vaccinated and unvaccinated individuals represented. Pregnant patients were at increased risk of hospitalization (odds ratio [OR] = 4.2; confidence interval [CI] = 2.0-8.6), intensive care unit admittance (OR = 4.5; CI = 1.2-14.2), and being placed on supplemental oxygen therapy (OR = 3.1; CI = 1.3-6.9). Individuals infected during their third trimester had higher mucosal anti-S IgG titers and lower viral RNA levels (P < 0.05) than those infected during their first or second trimesters. Pregnant individuals experiencing breakthrough infections due to the Omicron variant had reduced anti-S IgG compared to non-pregnant patients (P < 0.05). The observed increased severity of COVID-19 and reduced mucosal antibody responses particularly among pregnant participants infected with the Omicron variant suggest that maintaining high levels of SARS-CoV-2 immunity through booster vaccines may be important for the protection of this at-risk population.IMPORTANCEIn this retrospective observational cohort study, we analyzed remnant clinical samples from non-pregnant and pregnant individuals with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections who visited the Johns Hopkins Hospital System between October 2020 and May 2022. Disease severity, including intensive care unit admission, was greater among pregnant than non-pregnant patients. Vaccination reduced recovery of infectious virus and viral RNA levels in non-pregnant patients, but not in pregnant patients. In pregnant patients, increased nasopharyngeal viral RNA levels and recovery of infectious virus were associated with reduced mucosal IgG antibody responses, especially among women in their first trimester of pregnancy or experiencing breakthrough infections from Omicron variants. Taken together, this study provides insights into how pregnant patients are at greater risk of severe COVID-19. The novelty of this study is that it focuses on the relationship between the mucosal antibody response and its association with virus load and disease outcomes in pregnant people, whereas previous studies have focused on serological immunity. Vaccination status, gestational age, and SARS-CoV-2 omicron variant impact mucosal antibody responses and recovery of infectious virus from pregnant patients.

Pyrogenic and inflammatory mediators are produced by polarized M1 and M2 macrophages activated with D-dimer and SARS-CoV-2 spike immune complexes.

Lung macrophages are the first line of defense against invading respiratory pathogens including SARS-CoV-2, yet activation of macrophage in the lungs can lead to hyperinflammatory immune response seen in severe COVID-19. Here we used human M1 and M2 polarized macrophages as a surrogate model of inflammatory and regulatory macrophages and explored whether immune complexes (IC) containing spike-specific IgG can trigger aberrant cytokine responses in macrophages in the lungs and associated lymph nodes. We show that IC of SARS-CoV-2 recombinant S protein coated with spike-specific monoclonal antibody induced production of Prostaglandin E2 (PGE2) in non-polarized (M0) and in M1 and M2-type polarized human macrophages only in the presence of D-dimer (DD), a fibrinogen degradation product, associated with coagulopathy in COVID-19. Importantly, an increase in PGE2 was also observed in macrophages activated with DD and IC of SARS-CoV-2 pseudovirions coated with plasma from hospitalized COVID-19 patients but not from healthy subjects. Overall, the levels of PGE2 in macrophages activated with DD and IC were as follows: M1≫M2>M0 and correlated with the levels of spike binding antibodies and not with neutralizing antibody titers. All three macrophage subsets produced similar levels of IL-6 following activation with DD+IC, however TNFα, IL-1ß, and IL-10 cytokines were produced by M2 macrophages only. Our study suggests that high titers of spike or virion containing IC in the presence of coagulation byproducts (DD) can promote inflammatory response in macrophages in the lungs and associated lymph nodes and contribute to severe COVID-19.

Comparison of SARS-CoV-2 Hyperimmune Immunoglobulins Following Infection Plus Vaccination vs Infection.

This cross-sectional study compares the neutralizing titers of convalescent plasma and hyperimmune anti­SARS-CoV-2 intravenous immunoglobulins against circulating Omicron subvariants.

Reduced control of SARS-CoV-2 infection is associated with lower mucosal antibody responses in pregnant women.

Importance: Pregnant women are at increased risk of severe COVID-19, but the contribution of viral RNA load, the presence of infectious virus, and mucosal antibody responses remain understudied. Objective: To evaluate the association of COVID-19 outcomes following confirmed infection with vaccination status, mucosal antibody responses, infectious virus recovery and viral RNA levels in pregnant compared with non-pregnant women. Design: A retrospective observational cohort study of remnant clinical specimens from SARS-CoV-2 infected patients between October 2020-May 2022. Setting: Five acute care hospitals within the Johns Hopkins Health System (JHHS) in the Baltimore, MD-Washington, DC area. Participants: Participants included confirmed SARS-CoV-2 infected pregnant women and matched non-pregnant women (matching criteria included age, race/ethnicity, and vaccination status). Exposure: SARS-CoV-2 infection, with documentation of SARS-CoV-2 mRNA vaccination. Main Outcomes: The primary dependent measures were clinical COVID-19 outcomes, infectious virus recovery, viral RNA levels, and mucosal anti-spike (S) IgG titers from upper respiratory tract samples. Clinical outcomes were compared using odds ratios (OR), and measures of virus and antibody were compared using either Fisher's exact test, two-way ANOVA, or regression analyses. Results were stratified according to pregnancy, vaccination status, maternal age, trimester of pregnancy, and infecting SARS-CoV-2 variant. Resultss: A total of 452 individuals (117 pregnant and 335 non-pregnant) were included in the study, with both vaccinated and unvaccinated individuals represented. Pregnant women were at increased risk of hospitalization (OR = 4.2; CI = 2.0-8.6), ICU admittance, (OR = 4.5; CI = 1.2-14.2), and of being placed on supplemental oxygen therapy (OR = 3.1; CI =13-6.9). An age-associated decrease in anti-S IgG titer and corresponding increase in viral RNA levels (P< 0.001) was observed in vaccinated pregnant, but not non-pregnant, women. Individuals in their 3rd trimester had higher anti-S IgG titers and lower viral RNA levels (P< 0.05) than those in their 1st or 2nd trimesters. Pregnant individuals experiencing breakthrough infections due to the omicron variant had reduced anti-S IgG compared to non-pregnant women (P< 0.05). Conclusions and Relevance: In this cohort study, vaccination status, maternal age, trimester of pregnancy, and infecting SARS-CoV-2 variant were each identified as drivers of differences in mucosal anti-S IgG responses in pregnant compared with non-pregnant women. Observed increased severity of COVID-19 and reduced mucosal antibody responses particularly among pregnant participants infected with the Omicron variant suggest that maintaining high levels of SARS-CoV-2 immunity may be important for protection of this at-risk population.

Influenza vaccination reveals sex dimorphic imprints of prior mild COVID-19.

Acute viral infections can have durable functional impacts on the immune system long after recovery, but how they affect homeostatic immune states and responses to future perturbations remain poorly understood1-4. Here we use systems immunology approaches, including longitudinal multimodal single-cell analysis (surface proteins, transcriptome and V(D)J sequences) to comparatively assess baseline immune statuses and responses to influenza vaccination in 33 healthy individuals after recovery from mild, non-hospitalized COVID-19 (mean, 151 days after diagnosis) and 40 age- and sex-matched control individuals who had never had COVID-19. At the baseline and independent of time after COVID-19, recoverees had elevated T cell activation signatures and lower expression of innate immune genes including Toll-like receptors in monocytes. Male individuals who had recovered from COVID-19 had coordinately higher innate, influenza-specific plasmablast, and antibody responses after vaccination compared with healthy male individuals and female individuals who had recovered from COVID-19, in part because male recoverees had monocytes with higher IL-15 responses early after vaccination coupled with elevated prevaccination frequencies of 'virtual memory'-like CD8+ T cells poised to produce more IFNγ after IL-15 stimulation. Moreover, the expression of the repressed innate immune genes in monocytes increased by day 1 to day 28 after vaccination in recoverees, therefore moving towards the prevaccination baseline of the healthy control individuals. By contrast, these genes decreased on day 1 and returned to the baseline by day 28 in the control individuals. Our study reveals sex-dimorphic effects of previous mild COVID-19 and suggests that viral infections in humans can establish new immunological set-points that affect future immune responses in an antigen-agnostic manner.

Severe Acute Respiratory Syndrome Coronavirus 2 Hyperimmune Intravenous Human Immunoglobulins Neutralizes Omicron Subvariants BA.1, BA.2, BA.2.12.1, BA.3, and BA.4/BA.5 for Treatment of Coronavirus Disease 2019.

Our study demonstrates that neither 2020 convalescent plasma (CP) nor 2019/2020 intravenous immunoglobulin (IVIG) neutralizes Omicron subvariants BA.1 to BA.5. In contrast, 2020 hyperimmune anti-severe acute respiratory syndrome coronavirus 2 IVIG (hCoV-2IG) lots neutralized Omicron variants of concern, similar to results with 2022 CP from BA.1 breakthrough infections. Therefore, high-titer hCoV-2IG and CP could be evaluated for treatment of high-risk individuals infected with circulating Omicron subvariants.

Broadly neutralizing antibody induction by non-stabilized SARS-CoV-2 Spike mRNA vaccination in nonhuman primates.

Immunization with mRNA or viral vectors encoding spike with diproline substitutions (S-2P) has provided protective immunity against severe COVID-19 disease. How immunization with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) spike elicits neutralizing antibodies (nAbs) against difficult-to-neutralize variants of concern (VOCs) remains an area of great interest. Here, we compare immunization of macaques with mRNA vaccines expressing ancestral spike either including or lacking diproline substitutions, and show the diproline substitutions were not required for protection against SARS-CoV-2 challenge or induction of broadly neutralizing B cell lineages. One group of nAbs elicited by the ancestral spike lacking diproline substitutions targeted the outer face of the receptor binding domain (RBD), neutralized all tested SARS-CoV-2 VOCs including Omicron XBB.1.5, but lacked cross-Sarbecovirus neutralization. Structural analysis showed that the macaque broad SARS-CoV-2 VOC nAbs bound to the same epitope as a human broad SARS-CoV-2 VOC nAb, DH1193. Vaccine-induced antibodies that targeted the RBD inner face neutralized multiple Sarbecoviruses, protected mice from bat CoV RsSHC014 challenge, but lacked Omicron variant neutralization. Thus, ancestral SARS-CoV-2 spike lacking proline substitutions encoded by nucleoside-modified mRNA can induce B cell lineages binding to distinct RBD sites that either broadly neutralize animal and human Sarbecoviruses or recent Omicron VOCs.

Breadth of SARS-CoV-2 neutralization and protection induced by a nanoparticle vaccine.

Coronavirus vaccines that are highly effective against current and anticipated SARS-CoV-2 variants are needed to control COVID-19. We previously reported a receptor-binding domain (RBD)-sortase A-conjugated ferritin nanoparticle (scNP) vaccine that induced neutralizing antibodies against SARS-CoV-2 and pre-emergent sarbecoviruses and protected non-human primates (NHPs) from SARS-CoV-2 WA-1 infection. Here, we find the RBD-scNP induced neutralizing antibodies in NHPs against pseudoviruses of SARS-CoV and SARS-CoV-2 variants including 614G, Beta, Delta, Omicron BA.1, BA.2, BA.2.12.1, and BA.4/BA.5, and a designed variant with escape mutations, PMS20. Adjuvant studies demonstrate variant neutralization titers are highest with 3M-052-aqueous formulation (AF). Immunization twice with RBD-scNPs protect NHPs from SARS-CoV-2 WA-1, Beta, and Delta variant challenge, and protect mice from challenges of SARS-CoV-2 Beta variant and two other heterologous sarbecoviruses. These results demonstrate the ability of RBD-scNPs to induce broad neutralization of SARS-CoV-2 variants and to protect animals from multiple different SARS-related viruses. Such a vaccine could provide broad immunity to SARS-CoV-2 variants.

Antibody affinity and cross-variant neutralization of SARS-CoV-2 Omicron BA.1, BA.2 and BA.3 following third mRNA vaccination.

There is limited knowledge on durability of neutralization capacity and antibody affinity maturation generated following two versus three doses of SARS-CoV-2 mRNA vaccines in naïve versus convalescent individuals (hybrid immunity) against the highly transmissible Omicron BA.1, BA.2 and BA.3 subvariants. Virus neutralization titers against the vaccine-homologous strain (WA1) and Omicron sublineages are measured in a pseudovirus neutralization assay (PsVNA). In addition, antibody binding and antibody affinity against spike proteins from WA1, BA.1, and BA.2 is determined using surface plasmon resonance (SPR). The convalescent individuals who after SARS-CoV-2 infection got vaccinated develop hybrid immunity that shows broader neutralization activity and cross-reactive antibody affinity maturation against the Omicron BA.1 and BA.2 after either second or third vaccination compared with naïve individuals. Neutralization activity correlates with antibody affinity against Omicron subvariants BA.1 and BA.2 spikes. Importantly, at four months post-third vaccination the neutralization activity and antibody affinity against the Omicron subvariants is maintained and trended higher for the individuals with hybrid immunity compared with naïve adults. These findings about hybrid immunity resulting in superior immune kinetics, breadth, and durable high affinity antibodies support the need for booster vaccinations to provide effective protection from emerging SARS-CoV-2 variants like the rapidly spreading Omicron subvariants.

D-dimer and CoV-2 spike-immune complexes contribute to the production of PGE2 and proinflammatory cytokines in monocytes.

An overreactive inflammatory response and coagulopathy are observed in patients with severe form of COVID-19. Since increased levels of D-dimer (DD) are associated with coagulopathy in COVID-19, we explored whether DD contributes to the aberrant cytokine responses. Here we show that treatment of healthy human monocytes with DD induced a dose dependent increase in production of pyrogenic mediator, Prostaglandin E2 (PGE2) and inflammatory cytokines, IL-6 and IL-8. The DD-induced PGE2 and inflammatory cytokines were enhanced significantly by co-treatment with immune complexes (IC) of SARS CoV-2 recombinant S protein or of pseudovirus containing SARS CoV-2 S protein (PVCoV-2) coated with spike-specific chimeric monoclonal antibody (MAb) containing mouse variable and human Fc regions. The production of PGE2 and cytokines in monocytes activated with DD and ICs was sensitive to the inhibitors of ß2 integrin and FcγRIIa, and to the inhibitors of calcium signaling, Mitogen-Activated Protein Kinase (MAPK) pathway, and tyrosine-protein kinase. Importantly, strong increase in PGE2 and in IL-6/IL-8/IL-1ß cytokines was observed in monocytes activated with DD in the presence of IC of PVCoV-2 coated with plasma from hospitalized COVID-19 patients but not from healthy donors. The IC of PVCoV-2 with convalescent plasma induced much lower levels of PGE2 and cytokines compared with plasma from hospitalized COVID-19 patients. PGE2 and IL-6/IL-8 cytokines produced in monocytes activated with plasma-containing IC, correlated well with the levels of spike binding antibodies and not with neutralizing antibody titers. Our study suggests that a combination of high levels of DD and high titers of spike-binding antibodies that can form IC with SARS CoV-2 viral particles might accelerate the inflammatory status of lung infiltrating monocytes leading to increased lung pathology in patients with severe form of COVID-19.

Influenza vaccination and single cell multiomics reveal sex dimorphic immune imprints of prior mild COVID-19.

Viral infections can have profound and durable functional impacts on the immune system. There is an urgent need to characterize the long-term immune effects of SARS-CoV-2 infection given the persistence of symptoms in some individuals and the continued threat of novel variants. Here we use systems immunology, including longitudinal multimodal single cell analysis (surface proteins, transcriptome, and V(D)J sequences) from 33 previously healthy individuals after recovery from mild, non-hospitalized COVID-19 and 40 age- and sex-matched healthy controls with no history of COVID-19 to comparatively assess the post-infection immune status (mean: 151 days after diagnosis) and subsequent innate and adaptive responses to seasonal influenza vaccination. Identification of both sex-specific and -independent temporally stable changes, including signatures of T-cell activation and repression of innate defense/immune receptor genes (e.g., Toll-like receptors) in monocytes, suggest that mild COVID-19 can establish new post-recovery immunological set-points. COVID-19-recovered males had higher innate, influenza-specific plasmablast, and antibody responses after vaccination compared to healthy males and COVID-19-recovered females, partly attributable to elevated pre-vaccination frequencies of a GPR56 expressing CD8+ T-cell subset in male recoverees that are "poised" to produce higher levels of IFNγ upon inflammatory stimulation. Intriguingly, by day 1 post-vaccination in COVID-19-recovered subjects, the expression of the repressed genes in monocytes increased and moved towards the pre-vaccination baseline of healthy controls, suggesting that the acute inflammation induced by vaccination could partly reset the immune states established by mild COVID-19. Our study reveals sex-dimorphic immune imprints and in vivo functional impacts of mild COVID-19 in humans, suggesting that prior COVID-19, and possibly respiratory viral infections in general, could change future responses to vaccination and in turn, vaccines could help reset the immune system after COVID-19, both in an antigen-agnostic manner.

Immune Response to SARS-CoV-2 Vaccine and Following Breakthrough Omicron Infection in an Autoimmune Patient with Hashimoto's Thyroiditis, Pernicious Anemia, and Chronic Atrophic Autoimmune Gastritis: A Case Report.

In healthy adults, hybrid immunity induced by prior SARS-CoV-2 infection followed by two doses of mRNA vaccination provide protection against symptomatic SARS-CoV-2 infection. However, the role of hybrid immunity in autoimmune patients against Omicron is not well documented. Here, we report a young autoimmune patient with prior infection and two doses of mRNA-1273 vaccination who was exposed to Omicron and developed a symptomatic disease. Prior to Omicron infection, the patient had strong neutralizing antibody titers against the vaccine strain, but no neutralization of Omicron. Post Omicron infection, high neutralizing titers against Omicron were observed. Furthermore, enhanced neutralizing antibody titers against other variants of concern-Alpha, Beta, Gamma, and Delta-were observed, suggesting an expansion of cross-reactive memory B-cell response by the SARS-CoV-2 Omicron infection. Autoimmune patients may require careful monitoring of immune function over time to optimize booster vaccine administration.

Breadth of SARS-CoV-2 Neutralization and Protection Induced by a Nanoparticle Vaccine.

Coronavirus vaccines that are highly effective against SARS-CoV-2 variants are needed to control the current pandemic. We previously reported a receptor-binding domain (RBD) sortase A-conjugated ferritin nanoparticle (RBD-scNP) vaccine that induced neutralizing antibodies against SARS-CoV-2 and pre-emergent sarbecoviruses and protected monkeys from SARS-CoV-2 WA-1 infection. Here, we demonstrate SARS-CoV-2 RBD-scNP immunization induces potent neutralizing antibodies in non-human primates (NHPs) against all eight SARS-CoV-2 variants tested including the Beta, Delta, and Omicron variants. The Omicron variant was neutralized by RBD-scNP-induced serum antibodies with a mean of 10.6-fold reduction of ID50 titers compared to SARS-CoV-2 D614G. Immunization with RBD-scNPs protected NHPs from SARS-CoV-2 WA-1, Beta, and Delta variant challenge, and protected mice from challenges of SARS-CoV-2 Beta variant and two other heterologous sarbecoviruses. These results demonstrate the ability of RBD-scNPs to induce broad neutralization of SARS-CoV-2 variants and to protect NHPs and mice from multiple different SARS-related viruses. Such a vaccine could provide the needed immunity to slow the spread of and reduce disease caused by SARS-CoV-2 variants such as Delta and Omicron.