Immunogenicity and safety of Sinovac-CoronaVac booster vaccinations in 12-17- year-olds with clinically significant reactions from Pfizer-BNT162b2 vaccination.

Heterologous Sinovac-CoronaVac booster(s) in 12-17-year-olds who had a moderate/severe reaction to Pfizer-BNT162b2 mRNA vaccine was found to safe with no serious adverse events reported. In those primed with 1 dose of Pfizer-BNT162b2 vaccine, subsequent boosters with 2 doses of Sinovac-CoronaVac vaccines achieved neutralizing antibody levels which were comparable to those who had received 2 doses of Pfizer-BNT162b2 vaccines followed by 1 dose of Sinovac-CoronaVac vaccination. Adolescents with 1 Pfizer-BNT162b2 followed by 2 Sinovac-CoronaVac vaccines developed T-cell responses against broad peptides including membrane, nucleoprotein 1 and 2 but levels were highest for Spike protein and lasted until day 150 post-vaccination.

Human cytokeratin 1 plays a role in the interaction of Pteropine orthoreovirus with Hek293 cells but not HeLa cells.

Pteropine orthoreovirus (PRV) causes respiratory tract infections in humans. Despite its emergence as a zoonotic and respiratory virus, little is known about its cell tropism, which hampers progress in fully understanding its pathogenesis in humans. Hek293 cells are most susceptible to PRV infection, while HeLa cells are the least. Human cytokeratin 1 (CK1) was identified as the protein that interacts with PRV. The immunofluorescence assay and qPCR results revealed prior treatment with anti-CK1 may provide Hek293 cells protection against PRV. The KRT1-knockout Hek293 cells were less susceptible to PRV infection. Further study into the pathogenesis of PRV in humans is needed.

Longitudinal single cell atlas identifies complex temporal relationship between type I interferon response and COVID-19 severity.

Due to the paucity of longitudinal molecular studies of COVID-19, particularly those covering the early stages of infection (Days 1-8 symptom onset), our understanding of host response over the disease course is limited. We perform longitudinal single cell RNA-seq on 286 blood samples from 108 age- and sex-matched COVID-19 patients, including 73 with early samples. We examine discrete cell subtypes and continuous cell states longitudinally, and we identify upregulation of type I IFN-stimulated genes (ISGs) as the predominant early signature of subsequent worsening of symptoms, which we validate in an independent cohort and corroborate by plasma markers. However, ISG expression is dynamic in progressors, spiking early and then rapidly receding to the level of severity-matched non-progressors. In contrast, cross-sectional analysis shows that ISG expression is deficient and IFN suppressors such as SOCS3 are upregulated in severe and critical COVID-19. We validate the latter in four independent cohorts, and SOCS3 inhibition reduces SARS-CoV-2 replication in vitro. In summary, we identify complexity in type I IFN response to COVID-19, as well as a potential avenue for host-directed therapy.

Mucosal SARS-CoV-2 vaccination of rodents elicits superior systemic T central memory function and cross-neutralising antibodies against variants of concern.

BACKGROUND: COVID-19 vaccines used in humans are highly effective in limiting disease and death caused by the SARS-CoV-2 virus, yet improved vaccines that provide greater protection at mucosal surfaces, which could reduce break-through infections and subsequent transmission, are still needed. METHODS: Here we tested an intranasal (I.N.) vaccination with the receptor binding domain of Spike antigen of SARS-CoV-2 (S-RBD) in combination with the mucosal adjuvant mastoparan-7 compared with the sub-cutaneous (S.C.) route, adjuvanted by either M7 or the gold-standard adjuvant, alum, in mice, for immunological read-outs. The same formulation delivered I.N. or S.C. was tested in hamsters to assess efficacy. FINDINGS: I.N. vaccination improved systemic T cell responses compared to an equivalent dose of antigen delivered S.C. and T cell phenotypes induced by I.N. vaccine administration included enhanced polyfunctionality (combined IFN-γ and TNF expression) and greater numbers of T central memory (TCM) cells. These phenotypes were T cell-intrinsic and could be recalled in the lungs and/or brachial LNs upon antigen challenge after adoptive T cell transfer to naïve recipients. Furthermore, mucosal vaccination induced antibody responses that were similarly effective in neutralising the binding of the parental strain of S-RBD to its ACE2 receptor, but showed greater cross-neutralising capacity against multiple variants of concern (VOC), compared to S.C. vaccination. I.N. vaccination provided significant protection from lung pathology compared to unvaccinated animals upon challenge with homologous and heterologous SARS-CoV-2 strains in a hamster model. INTERPRETATION: These results highlight the role of nasal vaccine administration in imprinting an immune profile associated with long-term T cell retention and diversified neutralising antibody responses, which could be applied to improve vaccines for COVID-19 and other infectious diseases. FUNDING: This study was funded by Duke-NUS Medical School, the Singapore Ministry of Education, the National Medical Research Council of Singapore and a DBT-BIRAC Grant.

Advancing pathogen genomics in resource-limited settings.

Genomic sequencing has emerged as a powerful tool to enhance early pathogen detection and characterization with implications for public health and clinical decision making. Although widely available in developed countries, the application of pathogen genomics among low-resource, high-disease burden settings remains at an early stage. In these contexts, tailored approaches for integrating pathogen genomics within infectious disease control programs will be essential to optimize cost efficiency and public health impact. We propose a framework for embedding pathogen genomics within national surveillance plans across a spectrum of surveillance and laboratory capacities. We adopt a public health approach to genomics and examine its application to high-priority diseases relevant in resource-limited settings. For each grouping, we assess the value proposition for genomics to inform public health and clinical decision-making, alongside its contribution toward research and development of novel diagnostics, therapeutics, and vaccines.

Use of a point-of-care test to rapidly assess levels of SARS-CoV-2 nasal neutralising antibodies in vaccines and breakthrough infected individuals.

Despite SARS-CoV-2 vaccines eliciting systemic neutralising antibodies (nAbs), breakthrough infections still regularly occur. Infection helps to generate mucosal immunity, possibly reducing disease transmission. Monitoring mucosal nAbs is predominantly restricted to lab-based assays, which have limited application to the public. In this multi-site study, we used lateral-flow surrogate neutralisation tests to measure mucosal and systemic nAbs in vaccinated and breakthrough infected individuals in Australia and Singapore. Using three lateral flow assays to detect SARS-CoV-2 nAbs, we demonstrated that nasal mucosal nAbs were present in 71.4 (95% CI 56.3-82.9%) to 85.7% (95% CI 71.8-93.7%) of individuals with breakthrough infection (positivity rate was dependent upon the type of test), whereas only 20.7 (95% CI 17.1-49.4%) to 34.5% (95% CI 19.8-52.7%) of vaccinated individuals without breakthrough infection had detectible nasal mucosal nAbs. Of the individuals with breakthrough infection, collective mucosal anti-S antibody detection in confirmatory assays was 92.9% (95% CI 80.3-98.2%) of samples, while 72.4% (95% CI 54.1-85.5%) of the vaccinated individuals who had not experienced a breakthrough infection were positive to anti-S antibody. All breakthrough infected individuals produced systemic anti-N antibodies; however, these antibodies were not detected in the nasal cavity. Mucosal immunity is likely to play a role in limiting the transmission of SARS-CoV-2 and lateral flow neutralisation tests provide a rapid readout of mucosal nAbs at the point-of-care.

Interim results from a phase I randomized, placebo-controlled trial of novel SARS-CoV-2 beta variant receptor-binding domain recombinant protein and mRNA vaccines as a 4th dose booster.

BACKGROUND: SARS-CoV-2 booster vaccination should ideally enhance protection against variants and minimise immune imprinting. This Phase I trial evaluated two vaccines targeting SARS-CoV-2 beta-variant receptor-binding domain (RBD): a recombinant dimeric RBD-human IgG1 Fc-fusion protein, and an mRNA encoding a membrane-anchored RBD. METHODS: 76 healthy adults aged 18-64 y, previously triple vaccinated with licensed SARS-CoV-2 vaccines, were randomised to receive a 4th dose of either an adjuvanted (MF59®, CSL Seqirus) protein vaccine (5, 15 or 45 µg, N = 32), mRNA vaccine (10, 20, or 50 µg, N = 32), or placebo (saline, N = 12) at least 90 days after a 3rd boost vaccination or SARS-CoV-2 infection. Bleeds occurred on days 1 (prior to vaccination), 8, and 29. CLINICALTRIALS: govNCT05272605. FINDINGS: No vaccine-related serious or medically-attended adverse events occurred. The protein vaccine reactogenicity was mild, whereas the mRNA vaccine was moderately reactogenic at higher dose levels. Best anti-RBD antibody responses resulted from the higher doses of each vaccine. A similar pattern was seen with live virus neutralisation and surrogate, and pseudovirus neutralisation assays. Breadth of immune response was demonstrated against BA.5 and more recent omicron subvariants (XBB, XBB.1.5 and BQ.1.1). Binding antibody titres for both vaccines were comparable to those of a licensed bivalent mRNA vaccine. Both vaccines enhanced CD4+ and CD8+ T cell activation. INTERPRETATION: There were no safety concerns and the reactogenicity profile was mild and similar to licensed SARS-CoV-2 vaccines. Both vaccines showed strong immune boosting against beta, ancestral and omicron strains. FUNDING: Australian Government Medical Research Future Fund, and philanthropies Jack Ma Foundation and IFM investors.

Heterologous prime-boost with mRNA-1273 stimulates persistent neutralising antibodies in BBIBP-CorV-vaccinated individuals.

BBIBP-CorV inactivated vaccine is one of the most prevalent vaccines globally, but immune responses are far less studied than novel COVID-19 vaccine platforms. Longitudinal studies on BBIBP-CorV with homologous and heterologous booster doses are limited. This study follows a subset of participants from a national study comparing the immunogenicity of COVID-19 vaccines and levels of SARS-CoV-2 neutralising antibody (NAb). Homologous and heterologous booster dose significantly increased NAb levels in BBIBP-CorV-vaccinated individuals. Similar NAb levels were observed 1 month following BNT162b2 or mRNA-1273 booster. Interestingly, NAb persisted following mRNA-1273 booster (n = 95), but waned significantly at 6 and 9 months following BNT162b2 booster (n = 50; P > 0.001). The persistence of NAb was also observed following breakthrough infection. This study provides evidence that not all mRNA vaccines are equal in the longer term and should provide valuable information for policy makers planning booster programmes for BBIBP-CorV vaccinated populations.

BNT162b2 vaccine induced variant-specific immunity, safety and risk of Omicron breakthrough infection in children aged 5 to 11 years: a cohort study.

There is little information on BNT162b2 vaccine-induced variant-specific immunogenicity, safety data and dynamics of breakthrough infections in pediatric populations. We addressed these questions using a prospective two dose BNT162b2 (10 mcg) vaccination cohort study of healthy children 5-11 years in Singapore. Follow up included blood samples at scheduled visits, daily vaccination symptom diary and confirmation of SARS-CoV-2 infection. Surrogate virus neutralization test (sVNT) and spike-specific T cell responses against SARS-CoV-2 variants were performed. The mean age of 127 participants was 8.27 years (SD 1.95) and 51.2% were males. The median sVNT level against original variant after 1 dose and 2 dose vaccination was 61.4% and 95.1% respectively (p < 0.0001). Neutralizing antibodies against the Omicron variant was the lowest, median 22.4% (IQR 16.5-30.8). However, T cell IFN-γ cytokine response against Omicron variant was high and remained so about 4 months after vaccination. Fever rate increased significantly from 4% (dose 1) to 11.5% (dose 2). The risk of Omicron breakthrough infection decreased by 7.8% for every 1% increase in sVNT inhibition level measured after dose 2 vaccination. BNT162b2 vaccines were safe, induced good T cell responses but poor neutralizing antibodies against Omicron in children. Low neutralizing antibody levels post-vaccination was predictive of subsequent breakthrough infection.

Applications of VirScan to broad serological profiling of bat reservoirs for emerging zoonoses.

Introduction: Bats are important providers of ecosystem services such as pollination, seed dispersal, and insect control but also act as natural reservoirs for virulent zoonotic viruses. Bats host multiple viruses that cause life-threatening pathology in other animals and humans but, themselves, experience limited pathological disease from infection. Despite bats' importance as reservoirs for several zoonotic viruses, we know little about the broader viral diversity that they host. Bat virus surveillance efforts are challenged by difficulties of field capture and the limited scope of targeted PCR- or ELISA-based molecular and serological detection. Additionally, virus shedding is often transient, thus also limiting insights gained from nucleic acid testing of field specimens. Phage ImmunoPrecipitation Sequencing (PhIP-Seq), a broad serological tool used previously to comprehensively profile viral exposure history in humans, offers an exciting prospect for viral surveillance efforts in wildlife, including bats. Methods: Here, for the first time, we apply PhIP-Seq technology to bat serum, using a viral peptide library originally designed to simultaneously assay exposures to the entire human virome. Results: Using VirScan, we identified past exposures to 57 viral genera-including betacoronaviruses, henipaviruses, lyssaviruses, and filoviruses-in semi-captive Pteropus alecto and to nine viral genera in captive Eonycteris spelaea. Consistent with results from humans, we find that both total peptide hits (the number of enriched viral peptides in our library) and the corresponding number of inferred past virus exposures in bat hosts were correlated with poor bat body condition scores and increased with age. High and low body condition scores were associated with either seropositive or seronegative status for different viruses, though in general, virus-specific age-seroprevalence curves defied assumptions of lifelong immunizing infection, suggesting that many bat viruses may circulate via complex transmission dynamics. Discussion: Overall, our work emphasizes the utility of applying biomedical tools, like PhIP-Seq, first developed for humans to viral surveillance efforts in wildlife, while highlighting opportunities for taxon-specific improvements.

Mucosal antibody responses following Vaxzevria vaccination.

Mucosal antibodies play a key role in protection against breakthrough COVID-19 infections and emerging viral variants. Intramuscular adenovirus-based vaccination (Vaxzevria) only weakly induces nasal IgG and IgA responses, unless vaccinees have been previously infected. However, little is known about how Vaxzevria vaccination impacts the ability of mucosal antibodies to induce Fc responses, particularly against SARS-CoV-2 variants of concern (VoCs). Here, we profiled paired mucosal (saliva, tears) and plasma antibodies from COVID-19 vaccinated only vaccinees (uninfected, vaccinated) and COVID-19 recovered vaccinees (COVID-19 recovered, vaccinated) who both received Vaxzevria vaccines. SARS-CoV-2 ancestral-specific IgG antibodies capable of engaging FcγR3a were significantly higher in the mucosal samples of COVID-19 recovered Vaxzevria vaccinees in comparison with vaccinated only vaccinees. However, when IgG and FcγR3a engaging antibodies were tested against a panel of SARS-CoV-2 VoCs, the responses were ancestral-centric with weaker recognition of Omicron strains observed. In contrast, salivary IgA, but not plasma IgA, from Vaxzevria vaccinees displayed broad cross-reactivity across all SARS-CoV-2 VoCs tested. Our data highlight that while intramuscular Vaxzevria vaccination can enhance mucosal antibodies responses in COVID-19 recovered vaccinees, restrictions by ancestral-centric bias may have implications for COVID-19 protection. However, highly cross-reactive mucosal IgA could be key in addressing these gaps in mucosal immunity and may be an important focus of future SARS-CoV-2 vaccine development.

Betacoronaviruses SARS-CoV-2 and HCoV-OC43 infections in IGROV-1 cell line require aryl hydrocarbon receptor.

The emergence of novel betacoronaviruses has posed significant financial and human health burdens, necessitating the development of appropriate tools to combat future outbreaks. In this study, we have characterized a human cell line, IGROV-1, as a robust tool to detect, propagate, and titrate betacoronaviruses SARS-CoV-2 and HCoV-OC43. IGROV-1 cells can be used for serological assays, antiviral drug testing, and isolating SARS-CoV-2 variants from patient samples. Using time-course transcriptomics, we confirmed that IGROV-1 cells exhibit a robust innate immune response upon SARS-CoV-2 infection, recapitulating the response previously observed in primary human nasal epithelial cells. We performed genome-wide CRISPR knockout genetic screens in IGROV-1 cells and identified Aryl hydrocarbon receptor (AHR) as a critical host dependency factor for both SARS-CoV-2 and HCoV-OC43. Using DiMNF, a small molecule inhibitor of AHR, we observed that the drug selectively inhibits HCoV-OC43 infection but not SARS-CoV-2. Transcriptomic analysis in primary normal human bronchial epithelial cells revealed that DiMNF blocks HCoV-OC43 infection via basal activation of innate immune responses. Our findings highlight the potential of IGROV-1 cells as a valuable diagnostic and research tool to combat betacoronavirus diseases.

Clinical Course, Immunogenicity, and Efficacy of BNT162b2 mRNA Vaccination Against SARS-CoV-2 Infection in Liver Transplant Recipients.

Background: Immunocompromised individuals have been excluded from landmark studies of messenger RNA vaccinations for severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). In such patients, the response to vaccination may be blunted and may wane more quickly compared with immunocompetent patients. We studied the factors associated with decreased antibody response to SARS-CoV-2 vaccination and risk factors for subsequent breakthrough infections in liver transplant (LT) patients undergoing coronavirus disease 2019 vaccination with at least 2 doses of messenger RNA vaccine from April 28, 2021, to April 28, 2022. Methods: All LT recipients received at least 2 doses of the BNT162b2 (Pfizer BioNTech) vaccine 21 d apart. We measured the antibody response against the SARS-CoV-2 spike protein using the Roche Elecsys immunoassay to the receptor-binding domain of the SARS-CoV-2 spike protein, and the presence of neutralizing antibodies was measured by the surrogate virus neutralization test (cPass) before first and second doses of vaccination and also between 2 and 3 mo after the second dose of vaccination. Results: Ninety-three LT recipients who received 2 doses of BNT162b2 were included in the analysis. The mean time from LT was 110 ± 154 mo. After 2-dose vaccination, 38.7% of LT recipients (36/93) were vaccine nonresponders on the cPass assay compared with 20.4% (19/93) on the Roche S assay. On multivariable analysis, increased age and increased tacrolimus trough were found to be associated with poor neutralizing antibody response (P = 0.038 and 0.022, respectively). The use of antimetabolite therapy in conjunction with tacrolimus approached statistical significance (odds ratio 0.21; 95% confidence interval, 0.180-3.72; P = 0.062). Breakthrough infection occurred in 18 of 88 LT recipients (20.4%). Female gender was independently associated with breakthrough infections (P < 0.001). Conclusions: Among LT recipients, older age and higher tacrolimus trough levels were associated with poorer immune response to 2-dose SARS-CoV-2 vaccination. Further studies are needed to assess variables associated with breakthrough infections and, hence, who should be prioritized for booster vaccination.

Preexisting immunity restricts mucosal antibody recognition of SARS-CoV-2 and Fc profiles during breakthrough infections.

Understanding mucosal antibody responses from SARS-CoV-2 infection and/or vaccination is crucial to develop strategies for longer term immunity, especially against emerging viral variants. We profiled serial paired mucosal and plasma antibodies from COVID-19 vaccinated only vaccinees (vaccinated, uninfected), COVID-19-recovered vaccinees (recovered, vaccinated), and individuals with breakthrough Delta or Omicron BA.2 infections (vaccinated, infected). Saliva from COVID-19-recovered vaccinees displayed improved antibody-neutralizing activity, Fcγ receptor (FcγR) engagement, and IgA levels compared with COVID-19-uninfected vaccinees. Furthermore, repeated mRNA vaccination boosted SARS-CoV-2-specific IgG2 and IgG4 responses in both mucosa biofluids (saliva and tears) and plasma; however, these rises only negatively correlated with FcγR engagement in plasma. IgG and FcγR engagement, but not IgA, responses to breakthrough COVID-19 variants were dampened and narrowed by increased preexisting vaccine-induced immunity against the ancestral strain. Salivary antibodies delayed initiation following breakthrough COVID-19 infection, especially Omicron BA.2, but rose rapidly thereafter. Importantly, salivary antibody FcγR engagements were enhanced following breakthrough infections. Our data highlight how preexisting immunity shapes mucosal SARS-CoV-2-specific antibody responses and has implications for long-term protection from COVID-19.

Assays for Detecting Henipavirus Antibodies.

While molecular detection has increasingly become the detection method of choice for infectious diseases, antibody detection remains an important approach for diagnosis and surveillance. For henipaviruses, antibody detection methods such as ELISA and Western blot played a key role in the initial discovery of bats as the natural reservoir host. Here, we will describe three additional antibody detection methods (LIPS, Luminex, and pseudovirus systems), which can be used in most BSL2 laboratories without the need for live virus and a high containment BSL4 facility.

Comparison of infection and human immune responses of two SARS-CoV-2 strains in a humanized hACE2 NIKO mouse model.

The COVID-19 pandemic has sickened millions, cost lives and has devastated the global economy. Various animal models for experimental infection with SARS-CoV-2 have played a key role in many aspects of COVID-19 research. Here, we describe a humanized hACE2 (adenovirus expressing hACE2) NOD-SCID IL2Rγ-/- (NIKO) mouse model and compare infection with ancestral and mutant (SARS-CoV-2-∆382) strains of SARS-CoV-2. Immune cell infiltration, inflammation, lung damage and pro-inflammatory cytokines and chemokines was observed in humanized hACE2 NIKO mice. Humanized hACE2 NIKO mice infected with the ancestral and mutant SARS-CoV-2 strain had lung inflammation and production of pro-inflammatory cytokines and chemokines. This model can aid in examining the pathological basis of SARS-CoV-2 infection in a human immune environment and evaluation of therapeutic interventions.

Effectiveness of bivalent mRNA vaccines against medically attended symptomatic SARS-CoV-2 infection and COVID-19-related hospital admission among SARS-CoV-2-naive and previously infected individuals: a retrospective cohort study.

BACKGROUND: Emergence of the SARS-CoV-2 omicron (B.1.1.529) variant with high immune evasion has led to the development and roll-out of bivalent mRNA vaccines targeting original and omicron strains. However, real-world observational data on effectiveness of bivalent vaccines are scarce. We aimed to assess the relative effectiveness of a fourth vaccine dose with the BA.1-adapted or BA.4/BA.5-adapted bivalent vaccines against medically attended symptomatic SARS-CoV-2 infection and COVID-19-related hospital admission among SARS-CoV-2-naive and previously infected individuals in Singapore. METHODS: We conducted a retrospective cohort study among Singapore residents aged 18 years and older who had received three monovalent mRNA vaccine doses and were eligible for a fourth dose. Data were collected from official databases on COVID-19 cases and vaccinations maintained by the Singapore Ministry of Health. We analysed the incidence of medically attended symptomatic SARS-CoV-2 infection and COVID-19-related hospital admission between Oct 14, 2022, and Jan 31, 2023, by previous infection status and type of fourth vaccine dose received. Inverse probability-weighted Cox regressions were used to estimate hazard ratios (HRs). FINDINGS: 2 749 819 individuals were included in the analysis. For the SARS-CoV-2-naive group, a fourth monovalent vaccine dose did not confer additional protection over three monovalent doses against symptomatic infection (HR 1·09 [95% CI 1·07-1·11]), whereas the bivalent vaccine did provide additional protection (0·18 [0·17-0·19]). Among individuals with previous infection, the HR was 0·87 (95% CI 0·84-0·91) and 0·14 (0·13-0·15) with receipt of the fourth monovalent and bivalent doses, respectively. Against COVID-19-related hospital admission, the bivalent vaccine (HR 0·12 [95% CI 0·08-0·18] in SARS-CoV-2-naive participants and 0·04 [0·01-0·15] in previously infected participants) conferred greater benefit compared with the fourth monovalent dose (0·84 [0·77-0·91] in SARS-CoV-2-naive participants and 0·85 [0·69-1·04] in previously infected participants). INTERPRETATION: A fourth dose with the bivalent vaccine was substantially more effective against medically attended symptomatic SARS-CoV-2 infection and COVID-19-related hospital admission than four monovalent doses among both SARS-CoV-2-naive and previously infected individuals. Boosters with the bivalent vaccine might be preferred in this omicron-predominant pandemic, regardless of previous infection history. FUNDING: None.

Potent pan huACE2-dependent sarbecovirus neutralizing monoclonal antibodies isolated from a BNT162b2-vaccinated SARS survivor.

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern such as Omicron hampered efforts in controlling the ongoing coronavirus disease 2019 pandemic due to their ability to escape neutralizing antibodies induced by vaccination or prior infection, highlighting the need to develop broad-spectrum vaccines and therapeutics. Most human monoclonal antibodies (mAbs) reported to date have not demonstrated true pan-sarbecovirus neutralizing breadth especially against animal sarbecoviruses. Here, we report the isolation and characterization of highly potent mAbs targeting the receptor binding domain (RBD) of huACE2-dependent sarbecovirus from a SARS-CoV survivor vaccinated with BNT162b2. Among the six mAbs identified, one (E7) showed better huACE2-dependent sarbecovirus neutralizing potency and breadth than any other mAbs reported to date. Mutagenesis and cryo-electron microscopy studies indicate that these mAbs have a unique RBD contact footprint and that E7 binds to a quaternary structure-dependent epitope.