Enhanced mucosal B- and T-cell responses against SARS-CoV-2 after heterologous intramuscular mRNA prime/intranasal protein boost vaccination with a combination adjuvant. (preprint)

Current COVID-19 mRNA vaccines delivered intramuscularly (IM) induce effective systemic immunity, but with suboptimal immunity at mucosal sites, limiting their ability to impart sterilizing immunity. There is strong interest in rerouting immune responses induced in the periphery by parenteral vaccination to the portal entry site of respiratory viruses, such as SARS-CoV-2, by mucosal vaccination. We previously demonstrated the combination adjuvant, NE/IVT, consisting of a nanoemulsion (NE) and an RNA-based RIG-I agonist (IVT) induces potent systemic and mucosal immune responses in protein-based SARS-CoV-2 vaccines administered intranasally (IN). Herein, we demonstrate priming IM with mRNA followed by heterologous IN boosting with NE/IVT adjuvanted recombinant antigen induces strong mucosal and systemic antibody responses and enhances antigen-specific T cell responses in mucosa-draining lymph nodes compared to IM/IM and IN/IN prime/boost regimens. While all regimens induced cross-neutralizing antibodies against divergent variants and sterilizing immunity in the lungs of challenged mice, mucosal vaccination, either as homologous prime/boost or heterologous IN boost after IM mRNA prime was required to impart sterilizing immunity in the upper respiratory tract. Our data demonstrate the benefit of hybrid regimens whereby strong immune responses primed via IM vaccination are rerouted by IN vaccination to mucosal sites to provide optimal protection to SARS-CoV-2.

Preoperative COVID-19 Vaccination is Associated with Decreased Perioperative Mortality after Major Vascular Surgery (preprint)

Background: The objective of this study was to examine the effect of COVID-19 vaccination on perioperative outcomes after major vascular surgery. Methods: This is a multicenter retrospective study of patients who underwent major vascular surgery between December 2021 through August 2023. The primary outcome was all-cause mortality within 30 days of index operation or prior to hospital discharge. Multivariable models were used to examine the association between vaccination status and the primary outcome. Results: Of the total 85,424 patients included, 19161 (22.4%) were unvaccinated. Unvaccinated patients were younger compared to vaccinated patients (mean age 68.44 +/- 10.37 years vs 72.11 +/- 9.20 years, p <.001) and less likely to have comorbid conditions, including hypertension (87.2% vs 89.7%, p <.001), congestive heart failure (14.5% vs 15.9%, p <.001), chronic obstructive pulmonary disease (35.7% vs 36.3, p <.001) and renal failure requiring hemodialysis (1.4% vs 1.7%, p = .005). After risk factor adjustment, vaccination was associated with decreased mortality (OR 0.7, 95% CI 0.62 - 0.81, p <.0001). Stratification by procedure type demonstrated that vaccinated patients had decreased odds of mortality after open AAA (OR 0.6, 95% CI 0.42-0.97, p = 0.03), EVAR (OR 0.6, 95% CI 0.43-0.83, p 0.002), CAS (OR 0.7, 95% CI 0.51-0.88, p = 0.004) and infra-inguinal lower extremity interventions (OR 0.7, 95% CI 0.48-0.96, p = 0.03). Conclusions: COVID-19 vaccination is associated with reduced perioperative mortality in patients undergoing vascular surgery. This association is most pronounced for patients undergoing aortic aneurysm repair, carotid stenting and infrainguinal bypass.

Inhibition of SARS-CoV-2 Infection in Human Airway Epithelium with a Xeno-Nucleic Acid Aptamer (preprint)

Background: SARS-CoV-2, the agent responsible for the COVID-19 pandemic, enters cells through viral spike glycoprotein binding to the cellular receptor, angiotensin-converting enzyme 2 (ACE2). Given the lack of effective antivirals targeting SARS-CoV-2, we previously utilized systematic evolution of ligands by exponential enrichment (SELEX) and selected fluoro-arabino nucleic acid (FANA) aptamer R8-9 that was able to block the interaction between the viral receptor-binding domain and ACE2. Methods: Here, we further assessed FANA-R8-9 as an entry inhibitor in contexts that recapitulate infection in vivo. Results: We demonstrate that FANA-R8-9 inhibits spike-bearing pseudovirus particle uptake in cell lines. Then, using an in-vitro model of human airway epithelium (HAE) and SARS-CoV-2 virus, we show that FANA-R8-9 significantly reduces viral infection when added either at the time of inoculation, or several hours later. These results were specific to the R8-9 sequence, not the xeno-nucleic acid utilized to make the aptamer. Importantly, we also show that FANA-R8-9 is stable in HAE culture secretions and has no overt cytotoxic effects. Conclusions: Together, these results suggest that FANA-R8-9 effectively prevents infection by specific SARS-CoV-2 variants and indicate that aptamer technology could be utilized to target other clinically-relevant viruses in the respiratory mucosa.

Mitochondrial N-formyl methionine peptides contribute to exaggerated neutrophil activation in patients with COVID-19.

Neutrophil dysregulation is well established in COVID-19. However, factors contributing to neutrophil activation in COVID-19 are not clear. We assessed if N-formyl methionine (fMet) contributes to neutrophil activation in COVID-19. Elevated levels of calprotectin, neutrophil extracellular traps (NETs) and fMet were observed in COVID-19 patients (n = 68), particularly in critically ill patients, as compared to HC (n = 19, p < 0.0001). Of note, the levels of NETs were higher in ICU patients with COVID-19 than in ICU patients without COVID-19 (p < 0.05), suggesting a prominent contribution of NETs in COVID-19. Additionally, plasma from COVID-19 patients with mild and moderate/severe symptoms induced in vitro neutrophil activation through fMet/FPR1 (formyl peptide receptor-1) dependent mechanisms (p < 0.0001). fMet levels correlated with calprotectin levels validating fMet-mediated neutrophil activation in COVID-19 patients (r = 0.60, p = 0.0007). Our data indicate that fMet is an important factor contributing to neutrophil activation in COVID-19 disease and may represent a potential target for therapeutic intervention.

Comparison of thrombotic and clinical outcomes in SARS-CoV-2-pneumonia versus other viral pneumonia in an urban academic medical center.

BACKGROUND: Infection with viral pneumonia (PNA) is known to offset the coagulation cascade. Recent studies assessing novel SARS-CoV-2 infection observed a high frequency of systemic thrombotic events resulting in ambiguity if severity of infection or specific viral strain drive thrombosis and worsen clinical outcomes. Furthermore, limited data exists addressing SARS-CoV-2 in underrepresented patient populations. OBJECTIVES: Assess clinical outcomes events and death in patients diagnosed with SARS-CoV-2 pneumonia compared to patients with other types of viral pneumonia. METHODS: Retrospective cohort study evaluated electronic medical records in adult patients admitted to University of Illinois Hospital and Health Sciences System (UIHHSS) with primary diagnosis of SARS-CoV-2 PNA or other viral (H1N1 or H3N2) PNA between 10/01/2017 and 09/01/2020. Primary composite outcome was the following event incidence rates: death, ICU admission, infection, thrombotic complications, mechanical ventilation, renal replacement therapy, and major bleeding. RESULTS: Of 257 patient records, 199 and 58 patients had SARS-CoV-2 PNA and other viral PNA, respectively. There was no difference in primary composite outcome. Thrombotic events (n = 6, 3%) occurred solely in SARS-CoV-2 PNA patients in the ICU. A significantly higher incidence of renal replacement therapy (8.5% vs 0%, p=0.016) and mortality (15.6% vs 3.4%, p=0.048) occurred in the SARS-CoV-2 PNA group. Multivariable logistic regression analysis revealed age, presence of SARS-CoV-2, and ICU admission, aOR 1.07, 11.37, and 41.95 respectively, was significantly associated with mortality risk during hospitalization; race and ethnicity were not. CONCLUSION: Low overall incidence of thrombotic events occurred only in the SARS-CoV-2 PNA group. SARS-CoV-2 PNA may lead to higher incidence of clinical events than those observed in H3N2/H1N1 viral pneumonia, and that race/ethnicity does not drive mortality outcomes.

Understanding the Temporal, Regional, Demographic, and Policy Factors Influencing Counties' Daily Traffic Volume Reductions in Response to COVID-19

This research aims to understand temporal, regional, demographic, and policy factors that influenced travel reduction within the contiguous United States during the early period of the COVID-19 pandemic. Particularly, this research combines U.S. Census data, infection rates, and state-level mandates to determine their effects on daily, county-level vehicle miles traveled (VMT) estimations from March 1, 2020 to April 21, 2020. Specifically, this work generates metrics of VMT per capita, daily change in VMT, and VMT immediate reaction rates for every county in the U.S.A. and develops regression models to determine how these factors influence VMT rates over time. Results show that state-mandated orders were deployed in a pattern relative to their expected economic impact. Model results showed infection rates may have had a greater influence on forcing state policy adoption, ensuring reduced VMT, rather than the number of cases directly influencing individual travel to a significant degree. Additionally, counties with higher populations or labeled as urban counties saw a greater reduction in VMT across all three models compared with lower population and rural counties. Planners and policy makers in the future can utilize the results of this research to make better informed responses as well as to know the expected results of their actions.

Understanding the Temporal, Regional, Demographic, and Policy Factors Influencing Counties' Daily Traffic Volume Reductions in Response to COVID-19.

This research aims to understand temporal, regional, demographic, and policy factors that influenced travel reduction within the contiguous United States during the early period of the COVID-19 pandemic. Particularly, this research combines U.S. Census data, infection rates, and state-level mandates to determine their effects on daily, county-level vehicle miles traveled (VMT) estimations from March 1, 2020 to April 21, 2020. Specifically, this work generates metrics of VMT per capita, daily change in VMT, and VMT immediate reaction rates for every county in the U.S.A. and develops regression models to determine how these factors influence VMT rates over time. Results show that state-mandated orders were deployed in a pattern relative to their expected economic impact. Model results showed infection rates may have had a greater influence on forcing state policy adoption, ensuring reduced VMT, rather than the number of cases directly influencing individual travel to a significant degree. Additionally, counties with higher populations or labeled as urban counties saw a greater reduction in VMT across all three models compared with lower population and rural counties. Planners and policy makers in the future can utilize the results of this research to make better informed responses as well as to know the expected results of their actions.

Virtually the Same? Evaluating the Effectiveness of Remote Undergraduate Research Experiences.

In-person undergraduate research experiences (UREs) promote students' integration into careers in life science research. In 2020, the COVID-19 pandemic prompted institutions hosting summer URE programs to offer them remotely, raising questions about whether undergraduates who participate in remote research can experience scientific integration and whether they might perceive doing research less favorably (i.e., not beneficial or too costly). To address these questions, we examined indicators of scientific integration and perceptions of the benefits and costs of doing research among students who participated in remote life science URE programs in Summer 2020. We found that students experienced gains in scientific self-efficacy pre- to post-URE, similar to results reported for in-person UREs. We also found that students experienced gains in scientific identity, graduate and career intentions, and perceptions of the benefits of doing research only if they started their remote UREs at lower levels on these variables. Collectively, students did not change in their perceptions of the costs of doing research despite the challenges of working remotely. Yet students who started with low cost perceptions increased in these perceptions. These findings indicate that remote UREs can support students' self-efficacy development, but may otherwise be limited in their potential to promote scientific integration.

Computational design of nanomolar-binding antibodies specific to multiple SARS-CoV-2 variants by engineering a specificity switch of antibody 80R using RosettaAntibodyDesign (RAbD) results in potential generalizable therapeutic antibodies for novel SARS-CoV-2 virus.

The human infectious disease COVID-19 caused by the SARS-CoV-2 virus has become a major threat to global public health. Developing a vaccine is the preferred prophylactic response to epidemics and pandemics. However, for individuals who have contracted the disease, the rapid design of antibodies that can target the SARS-CoV-2 virus fulfils a critical need. Further, discovering antibodies that bind multiple variants of SARS-CoV-2 can aid in the development of rapid antigen tests (RATs) which are critical for the identification and isolation of individuals currently carrying COVID-19. Here we provide a proof-of-concept study for the computational design of high-affinity antibodies that bind to multiple variants of the SARS-CoV-2 spike protein using RosettaAntibodyDesign (RAbD). Well characterized antibodies that bind with high affinity to the SARS-CoV-1 (but not SARS-CoV-2) spike protein were used as templates and re-designed to bind the SARS-CoV-2 spike protein with high affinity, resulting in a specificity switch. A panel of designed antibodies were experimentally validated. One design bound to a broad range of variants of concern including the Omicron, Delta, Wuhan, and South African spike protein variants.

Pirfenidone in fibrotic hypersensitivity pneumonitis: a double-blind, randomised clinical trial of efficacy and safety.

BACKGROUND: Fibrotic hypersensitivity pneumonitis (FHP) is an irreversible lung disease with high morbidity and mortality. We sought to evaluate the safety and effect of pirfenidone on disease progression in such patients. METHODS: We conducted a single-centre, randomised, double-blinded, placebo-controlled trial in adults with FHP and disease progression. Patients were assigned in a 2:1 ratio to receive either oral pirfenidone (2403 mg/day) or placebo for 52 weeks. The primary end point was the mean absolute change in the per cent predicted forced vital capacity (FVC%). Secondary end points included progression-free survival (PFS, time to a relative decline ≥10% in FVC and/or diffusing capacity of the lung for carbon monoxide (DLCO), acute respiratory exacerbation, a decrease of ≥50 m in the 6 min walk distance, increase or introduction of immunosuppressive drugs or death), change in FVC slope and mean DLCO%, hospitalisations, radiological progression of lung fibrosis and safety. RESULTS: After randomising 40 patients, enrolment was interrupted by the COVID-19 pandemic. There was no significant between-group difference in FVC% at week 52 (mean difference -0.76%, 95% CI -6.34 to 4.82). Pirfenidone resulted in a lower rate of decline in the adjusted FVC% at week 26 and improved PFS (HR 0.26, 95% CI 0.12 to 0.60). Results for other secondary end points showed no significant difference between groups. No deaths occurred in the pirfenidone group and one death (respiratory) occurred in the placebo group. There were no treatment-emergent serious adverse events. CONCLUSIONS: The trial was underpowered to detect a difference in the primary end point. Pirfenidone was found to be safe and improved PFS in patients with FHP. TRIAL REGISTRATION MUMBER: NCT02958917.

Population Segmentation for COVID-19 Vaccine Outreach: A Clustering Analysis and Implementation in Missouri.

OBJECTIVES: The purpose of this work was to segment the Missouri population into unique groups related to COVID-19 vaccine acceptance using data science and behavioral science methods to develop tailored vaccine outreach strategies. METHODS: Cluster analysis techniques were applied to a large data set that aggregated vaccination data with behavioral and demographic data from the American Community Survey and Deloitte's HealthPrism™ data set. Outreach recommendations were developed for each cluster, specific to each group's practical and motivational barriers to vaccination. RESULTS: Following selection procedures, 10 clusters-or segments-of census tracts across Missouri were identified on the basis of k -means clustering analysis of 18 different variables. Each cluster exhibited unique geographic, demographic, socioeconomic, and behavioral patterns, and outreach strategies were developed on the basis of each cluster's practical and motivational barriers. DISCUSSION: The segmentation analysis served as the foundation for "working groups" comprising the 115 local public health agencies (LPHAs) across the state. LPHAs with similar community segments in their service area were grouped together to discuss their communities' specific challenges, share lessons learned, and brainstorm new approaches. The working groups provided a novel way for public health to organize and collaborate across the state. Widening the aperture beyond Missouri, population segmentation via cluster analysis is a promising approach for public health practitioners interested in developing a richer understanding of the types of populations they serve. By pairing segmentation with behavioral science, practitioners can develop outreach programs and communications campaigns that are personalized to the specific behavioral barriers and needs of the population in focus. While our work focused on COVID-19, this approach has broad applicability to enhance the way public health practitioners understand the populations they serve to deliver more tailored services.

Long-term persistence of RBD+ memory B cells encoding neutralizing antibodies in SARS-CoV-2 infection.

Considerable concerns relating to the duration of protective immunity against severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) exist, with evidence of antibody titers declining rapidly after infection and reports of reinfection. Here, we monitor the antibody responses against SARS-CoV-2 receptor-binding domain (RBD) for up to 6 months after infection. While antibody titers are maintained, ∼13% of the cohort's neutralizing responses return to background. However, encouragingly, in a selected subset of 13 participants, 12 have detectable RBD-specific memory B cells and these generally are increasing out to 6 months. Furthermore, we are able to generate monoclonal antibodies with SARS-CoV-2 neutralizing capacity from these memory B cells. Overall, our study suggests that the loss of neutralizing antibodies in plasma may be countered by the maintenance of neutralizing capacity in the memory B cell repertoire.

Accelerated Cardiac Allograft Vasculopathy in an Orthotopic Heart Transplant Recipient with Prior COVID-19.

BACKGROUND Cardiac allograft vasculopathy (CAV) is a post-orthotopic heart transplant (OHT) complication driven by intimal smooth muscle proliferation and immune hyperactivity to donor heart tissue. Accelerated CAV leads to allograft failure within 1 year after receiving a normal angiogram result. Viruses can contribute to CAV development, but CAV after SARS-CoV-2 infection has not been reported to date. CASE REPORT A 48-year-old man, 5 years after OHT for non-ischemic cardiomyopathy, was admitted to the Cardiac Care Unit with 3 days of abdominal pain, dyspnea, and palpitations. His medical history included hyperlipidemia and insulin-dependent diabetes. He was compliant with all medications. Two months prior, he had a mild COVID-19 case. An echocardiogram and coronary angiogram 6 and 9 months prior, respectively, were unremarkable. Right and left heart catheterization demonstrated increased filling pressures, a cardiac index of 1.7 L/ml/m², and diffuse vasculopathy most severe in the LAD artery. Flow could not be restored despite repeated ballooning and intra-catheter adenosine. Empiric ionotropic support, daily high-dose methylprednisolone, and plasmapheresis were started. A few days later, the patient had cardiac arrest requiring venoarterial extracorporeal membranous oxygenation. Given CAV's irreversibility, re-transplantation was considered, but the patient had an episode of large-volume hemoptysis and remained clinically unstable for transplant. The patient died while on palliative care. CONCLUSIONS Our patient developed accelerated CAV 2 months after having COVID-19. While CAV has known associations with certain viruses, its incidence after SARS-CoV-2 infection is unknown. Further research is needed to determine if prior SARS-CoV-2 infection is a risk factor for development of CAV in OHT recipients.

Neutrophilic inflammation promotes SARS-CoV-2 infectivity and augments the inflammatory responses in airway epithelial cells.

Introduction: In response to viral infection, neutrophils release inflammatory mediators as part of the innate immune response, contributing to pathogen clearance through virus internalization and killing. Pre- existing co-morbidities correlating to incidence to severe COVID-19 are associated with chronic airway neutrophilia. Furthermore, examination of COVID-19 explanted lung tissue revealed a series of epithelial pathologies associated with the infiltration and activation of neutrophils, indicating neutrophil activity in response to SARS-CoV-2 infection. Methods: To determine the impact of neutrophil-epithelial interactions on the infectivity and inflammatory responses to SARS-CoV-2 infection, we developed a co-culture model of airway neutrophilia. This model was infected with live SARS-CoV-2 virus the epithelial response to infection was evaluated. Results: SARS-CoV-2 infection of airway epithelium alone does not result in a notable pro-inflammatory response from the epithelium. The addition of neutrophils induces the release of proinflammatory cytokines and stimulates a significantly augmented proinflammatory response subsequent SARS-CoV-2 infection. The resulting inflammatory responses are polarized with differential release from the apical and basolateral side of the epithelium. Additionally, the integrity of the \epithelial barrier is impaired with notable epithelial damage and infection of basal stem cells. Conclusions: This study reveals a key role for neutrophil-epithelial interactions in determining inflammation and infectivity.

Prognostic value of severe acute respiratory syndrome coronavirus-2 viral load and antibodies in patients hospitalized with COVID-19.

Observational studies have identified the potential prognostic value for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) viral load and anti-SARS-CoV-2 antibodies in coronavirus disease 2019 (COVID-19). However, viral load in nasopharyngeal (NP) swabs produced inconsistent results in prognostic analyses, and the prognostic value of viral load or antibodies has not been confirmed in large clinical trials. COVACTA and REMDACTA were double-blind, randomized, controlled trials with a combined enrollment of 1078 patients hospitalized with COVID-19 treated with tocilizumab or placebo in COVACTA or tocilizumab plus remdesivir or placebo plus remdesivir in REMDACTA. We assessed the potential prognostic value of NP and serum SARS-CoV-2 viral load and serum anti-SARS-CoV-2 antibodies at baseline as biomarkers for clinical outcomes in patients enrolled in these trials. In adjusted Cox proportional hazard models, serum viral load was a more reliable predictor of clinical outcomes than NP viral load; high serum viral load was associated with higher risk for death and mechanical ventilation/death and lower likelihood of hospital discharge (high vs. negative viral load hazard ratios [95% confidence interval {CI}] were 2.87 [1.57-5.25], 3.86 [2.23-6.68], and 0.23 [0.14-0.36], respectively, in COVACTA and 8.11 [2.95-22.26], 10.29 [4.5-23.55], and 0.21 [0.15-0.29], respectively, in REMDACTA) and high serum viral load correlated with levels of inflammatory cytokines and lung damage biomarkers. High anti-SARS-CoV-2 spike protein antibody (ACOV2S) levels were associated with higher likelihood of hospital discharge (high vs. below the limit of quantification hazard ratios [95% CI] were 2.55 [1.59-4.08] for COVACTA and 1.54 [1.13-2.09] for REMDACTA). These results support the role of baseline SARS-CoV-2 serum viral load and ACOV2S antibody titers in predicting clinical outcomes for patients hospitalized with COVID-19.

Internal reference genes with the potential for normalizing quantitative PCR results for oral fluid specimens.

In basic research, testing of oral fluid specimens by real-time quantitative polymerase chain reaction (qPCR) has been used to evaluate changes in gene expression levels following experimental treatments. In diagnostic medicine, qPCR has been used to detect DNA/RNA transcripts indicative of bacterial or viral infections. Normalization of qPCR using endogenous and exogenous reference genes is a well-established strategy for ensuring result comparability by controlling sample-to-sample variation introduced during sampling, storage, and qPCR testing. In this review, the majority of recent publications in human (n = 136) and veterinary (n = 179) medicine did not describe the use of internal reference genes in qPCRs for oral fluid specimens (52.9% animal studies; 57.0% human studies). However, the use of endogenous reference genes has not been fully explored or validated for oral fluid specimens. The lack of valid internal reference genes inherent to the oral fluid matrix will continue to hamper the reliability, reproducibility, and generalizability of oral fluid qPCR assays until this issue is addressed.

Rapid Deployment of Whole Slide Imaging for Primary Diagnosis in Surgical Pathology at Stanford Medicine.

CONTEXT.­: Stanford Pathology began stepwise subspecialty implementation of whole slide imaging (WSI) in 2018 soon after the first US Food and Drug Administration approval. In 2020, during the COVID-19 pandemic, the Centers for Medicare & Medicaid Services waived the requirement for pathologists to perform diagnostic tests in Clinical Laboratory Improvement Amendments (CLIA)-licensed facilities. This encouraged rapid implementation of WSI across all surgical pathology subspecialties. OBJECTIVE.­: To present our experience with validation and implementation of WSI at a large academic medical center encompassing a caseload of more than 50 000 cases per year. DESIGN.­: Validation was performed independently for 3 subspecialty services with a diagnostic concordance threshold above 95%. Analysis of user experience, staffing, infrastructure, and information technology was performed after department-wide expansion. RESULTS.­: Diagnostic concordance was achieved in 96% of neuropathology cases, 100% of gynecologic pathology cases, and 98% of immunohistochemistry cases. After full implementation, 8 high-capacity scanners were operational, with whole slide images generated on greater than 2000 slides per weekday, accounting for approximately 80% of histologic slides at Stanford Medicine. Multiple modifications in workflow and information technology were needed to improve performance. Within months of full implementation, most attending pathologists and trainees had adopted WSI for primary diagnosis. CONCLUSIONS.­: WSI across all surgical subspecialities is achievable at scale at an academic medical center; however, adoption required flexibility to adjust workflows and develop tailored solutions. WSI at scale supported the health and safety of medical staff while facilitating high-quality patient care and education during COVID-19 restrictions.

Development of Fully Human, Bispecific Antibodies that Effectively Block Omicron Variant Pseudovirus Infections (preprint)

The emergence of highly immune invasive and transmissible variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has decreased the effectiveness of existing vaccines. It is, therefore, critical to develop effective and safe therapeutics for SARS-CoV-2 infections, especially for the most vulnerable and immunocompromised patients. Neutralizing antibodies have been shown to be successful at preventing severe disease from early SARS-CoV-2 strains, although their efficacy has diminished with the emergence of new variants. Here, we aim to develop fully human and broadly neutralizing monoclonal (mAb) and bispecific (BsAb) antibodies against SARS-CoV-2 and its variants. Specifically, we first identified two antibodies from human transgenic mice that bind to the receptor binding domain (RBD) of the SARS-CoV-2 spike protein and are capable of neutralizing SARS-CoV-2 and variants of concern with high to moderate affinity. Two non-competing clones with the highest affinity and functional blocking of ACE2 binding were then selected to be engineered into two BsAbs, which were then demonstrated to have relatively improved affinity, ACE2 blocking ability, and pseudovirus inhibition against several variants, including Omicron (B.1.1.529). Our findings provide one mAb candidate and two bsAb candidates for consideration of further clinical development and suggest that the bispecific format may be more effective than mAbs for SARS-CoV-2 treatment.