scholarly journals ChAdOx1 nCoV-19 (AZD1222) protects Syrian hamsters against SARS-CoV-2 B.1.351 and B.1.1.7

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Robert J. Fischer ◽  
Neeltje van Doremalen ◽  
Danielle R. Adney ◽  
Claude Kwe Yinda ◽  
Julia R. Port ◽  
...  
Keyword(s):  
Single Dose ◽  
Vaccine Efficacy ◽  
Infectious Virus ◽  
Neutralizing Antibody ◽  
Subgenomic Rna ◽  
Syrian Hamsters ◽  
Fold Reduction ◽  
Histopathological Evaluation ◽  
Gross Lesions ◽  
Pulmonary Pathology

AbstractWe investigated ChAdOx1 nCoV-19 (AZD1222) vaccine efficacy against SARS-CoV-2 variants of concern (VOCs) B.1.1.7 and B.1.351 in Syrian hamsters. We previously showed protection against SARS-CoV-2 disease and pneumonia in hamsters vaccinated with a single dose of ChAdOx1 nCoV-19. Here, we observe a 9.5-fold reduction of virus neutralizing antibody titer in vaccinated hamster sera against B.1.351 compared to B.1.1.7. Vaccinated hamsters challenged with B.1.1.7 or B.1.351 do not lose weight compared to control animals. In contrast to control animals, the lungs of vaccinated animals do not show any gross lesions. Minimal to no viral subgenomic RNA (sgRNA) and no infectious virus can be detected in lungs of vaccinated animals. Histopathological evaluation shows extensive pulmonary pathology caused by B.1.1.7 or B.1.351 replication in the control animals, but none in the vaccinated animals. These data demonstrate the effectiveness of the ChAdOx1 nCoV-19 vaccine against clinical disease caused by B.1.1.7 or B.1.351 VOCs.

scholarly journals ChAdOx1 nCoV-19 (AZD1222) protects hamsters against SARS-CoV-2 B.1.351 and B.1.1.7 disease

2021 ◽  
Author(s):  
Robert J. Fischer ◽  
Neeltje van Doremalen ◽  
Danielle R. Adney ◽  
Claude Kwe Yinda ◽  
Julia R. Port ◽  
...  
Keyword(s):  
Single Dose ◽  
Antibody Titer ◽  
Vaccine Efficacy ◽  
Infectious Virus ◽  
Neutralizing Antibody ◽  
Subgenomic Rna ◽  
Fold Reduction ◽  
Histopathological Evaluation ◽  
Gross Lesions ◽  
Pulmonary Pathology

AbstractWe investigated ChAdOx1 nCoV-19 (AZD1222) vaccine efficacy against SARS-CoV-2 variants of concern (VOCs) B.1.1.7 and B.1.351 in Syrian hamsters. We previously showed protection against SARS-CoV-2 disease and pneumonia in hamsters vaccinated with a single dose of ChAdOx1 nCoV-19. Here, we observed a 9.5-fold reduction of virus neutralizing antibody titer in vaccinated hamster sera against B.1.351 compared to B.1.1.7. Vaccinated hamsters challenged with B.1.1.7 or B.1.351 did not lose weight compared to control animals. In contrast to control animals, the lungs of vaccinated animals did not show any gross lesions. Minimal to no viral subgenomic RNA (sgRNA) and no infectious virus was detected in lungs of vaccinated animals. Histopathological evaluation showed extensive pulmonary pathology caused by B.1.1.7 or B.1.351 replication in the control animals, but none in the vaccinated animals. These data demonstrate the effectiveness of the ChAdOx1 nCoV-19 vaccine against clinical disease caused by B.1.1.7 or B.1.351 VOCs.

scholarly journals Multivalent nanoparticle-based vaccines protect hamsters against SARS-CoV-2 after a single immunization

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Shiho Chiba ◽  
Steven J. Frey ◽  
Peter J. Halfmann ◽  
Makoto Kuroda ◽  
Tadashi Maemura ◽  
...  
Keyword(s):  
Coat Protein ◽  
Infectious Virus ◽  
Neutralizing Antibody ◽  
Vaccine Platform ◽  
Death Rates ◽  
Widespread Distribution ◽  
Syrian Hamsters ◽  
Vaccine Trials ◽  
Multiple Copies ◽  
Antibody Titers

AbstractThe COVID-19 pandemic continues to wreak havoc as worldwide SARS-CoV-2 infection, hospitalization, and death rates climb unabated. Effective vaccines remain the most promising approach to counter SARS-CoV-2. Yet, while promising results are emerging from COVID-19 vaccine trials, the need for multiple doses and the challenges associated with the widespread distribution and administration of vaccines remain concerns. Here, we engineered the coat protein of the MS2 bacteriophage and generated nanoparticles displaying multiple copies of the SARS-CoV-2 spike (S) protein. The use of these nanoparticles as vaccines generated high neutralizing antibody titers and protected Syrian hamsters from a challenge with SARS-CoV-2 after a single immunization with no infectious virus detected in the lungs. This nanoparticle-based vaccine platform thus provides protection after a single immunization and may be broadly applicable for protecting against SARS-CoV-2 and future pathogens with pandemic potential.

scholarly journals Multivalent Nanoparticle-Based Vaccines Protect Hamsters Against SARS-CoV-2 After a Single Immunization

2020 ◽  
Author(s):  
Shiho Chiba ◽  
Steven J. Frey ◽  
Peter J. Halfmann ◽  
Makoto Kuroda ◽  
Tadashi Maemura ◽  
...  
Keyword(s):  
Coat Protein ◽  
Infectious Virus ◽  
Neutralizing Antibody ◽  
Vaccine Platform ◽  
Death Rates ◽  
Widespread Distribution ◽  
Syrian Hamsters ◽  
Vaccine Trials ◽  
Multiple Copies ◽  
Antibody Titers

Abstract The COVID-19 pandemic continues to wreak havoc as worldwide SARS-CoV-2 infection, hospitalization, and death rates climb unabated. Effective vaccines remain the most promising approach to counter SARS-CoV-2. Yet, while promising results are emerging from COVID-19 vaccine trials, the need for multiple doses and the challenges associated with the widespread distribution and administration of vaccines remain concerns. Here, we engineered the coat protein of the MS2 bacteriophage1,2 and generated nanoparticles displaying multiple copies of the SARS-CoV-2 spike (S) protein. The use of these nanoparticles as vaccines generated high neutralizing antibody titers and protected Syrian hamsters3 from a challenge with SARS-CoV-2 after a single immunization with no infectious virus detected in the lungs. This nanoparticle-based vaccine platform thus provides protection after a single immunization and may be broadly applicable for protecting against SARS-CoV-2 and future pathogens with pandemic potential.

scholarly journals Contrasting Adult and Infant Immune Responses to HIV Infection and Vaccination

2015 ◽  
Vol 23 (2) ◽  
pp. 84-94 ◽  
Author(s):  
David R. Martinez ◽  
Sallie R. Permar ◽  
Genevieve G. Fouda
Keyword(s):  
Immune Responses ◽  
Hiv Infection ◽  
Vaccine Efficacy ◽  
Neutralizing Antibody ◽  
Hiv Vaccine ◽  
Antibody Responses ◽  
Hiv Vaccines ◽  
Vaccine Candidates ◽  
Protective Antibodies ◽  
Pediatric Populations

ABSTRACTExtensive studies have demonstrated that infant immune responses are distinct from those of adults. Despite these differences, infant immunization can elicit protective immune responses at levels comparable to or, in some cases, higher than adult immune responses to many vaccines. To date, only a few HIV vaccine candidates have been tested in infant populations, and none of them evaluated vaccine efficacy. Recent exciting studies showing that HIV-infected infants can develop broad neutralizing antibody responses and that some HIV vaccine regimens can elicit high levels of potentially protective antibodies in infants provide support for the development and testing of HIV vaccines in pediatric populations. In this review, we discuss the differences in adult and infant immune responses in the setting of HIV infection and vaccination.

scholarly journals Immunogenicity and efficacy of one and two doses of Ad26.COV2.S COVID vaccine in adult and aged NHP

2021 ◽  
Vol 218 (7) ◽  
Author(s):  
Laura Solforosi ◽  
Harmjan Kuipers ◽  
Mandy Jongeneelen ◽  
Sietske K. Rosendahl Huber ◽  
Joan E.M. van der Lubbe ◽  
...  
Keyword(s):  
Single Dose ◽  
Protective Efficacy ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Upper Respiratory Tract ◽  
T Helper ◽  
Th Cell ◽  
Upper Respiratory ◽  
Early Indication ◽  
Dose Vaccine

Safe and effective coronavirus disease–19 (COVID-19) vaccines are urgently needed to control the ongoing pandemic. While single-dose vaccine regimens would provide multiple advantages, two doses may improve the magnitude and durability of immunity and protective efficacy. We assessed one- and two-dose regimens of the Ad26.COV2.S vaccine candidate in adult and aged nonhuman primates (NHPs). A two-dose Ad26.COV2.S regimen induced higher peak binding and neutralizing antibody responses compared with a single dose. In one-dose regimens, neutralizing antibody responses were stable for at least 14 wk, providing an early indication of durability. Ad26.COV2.S induced humoral immunity and T helper cell (Th cell) 1–skewed cellular responses in aged NHPs that were comparable to those in adult animals. Aged Ad26.COV2.S-vaccinated animals challenged 3 mo after dose 1 with a SARS-CoV-2 spike G614 variant showed near complete lower and substantial upper respiratory tract protection for both regimens. Neutralization of variants of concern by NHP sera was reduced for B.1.351 lineages while maintained for the B.1.1.7 lineage independent of Ad26.COV2.S vaccine regimen.

scholarly journals Neutralization Assessments Reveal High Cardiothoracic Ratio and Old Age as Independent Predictors of Low Neutralizing Antibody Titers in Hemodialysis Patients Receiving a Single Dose of COVID-19 Vaccine

2022 ◽  
Vol 12 (1) ◽  
pp. 68
Author(s):  
Chun-Yu Chen ◽  
Kuan-Ting Liu ◽  
Shin-Ru Shih ◽  
Jung-Jr Ye ◽  
Yih-Ting Chen ◽  
...  
Keyword(s):  
Single Dose ◽  
Old Age ◽  
Neutralizing Antibodies ◽  
Additive Model ◽  
Humoral Response ◽  
Neutralizing Antibody ◽  
Enzyme Linked Immunosorbent Assay ◽  
Healthy Controls ◽  
Neutralization Titer ◽  
Cardiothoracic Ratio

Background: Data are lacking regarding predictors of quantification of neutralizing antibodies (nAbs) based on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) 50% neutralization titer (NT50) after a single dose of COVID-19 vaccine in hemodialysis (HD) patients. Methods: This prospective single-center study enrolled 200 HD patients and 82 healthy subjects to estimate antibodies against the SARS-CoV-2 viral spike protein 1 and receptor-binding domain after a first dose of a COVID-19 vaccine (ChAdOx1 or mRNA-1273), measured by enzyme-linked immunosorbent assay and applied spline-based generalized additive model regression analysis to predict NT50 converted to international units. Results: After the first dose of ChAdOx1, multiple linear regression showed that age (p = 0.011) and cardiothoracic ratio (p = 0.002) were negatively associated with NT50. Older age (OR = 0.958, p = 0.052) and higher cardiothoracic ratio (OR < 0.001, p = 0.037) could predict negative humoral response (NT50 < 35.13 IU/mL). NT50 was lower in HD patients compared with healthy controls receiving ChAdOx1 (10.68 vs. 43.01 IU/m, p < 0.001) or mRNA-1273 (36.39 vs. 262.2 IU/mL, p < 0.001). ChAdOx1 elicited lower GMTs than mRNA-1273 in the HD cohort (10.68 vs. 36.39 IU/mL, p < 0.001) and in healthy controls (43.01 vs. 262.22 IU/mL, p < 0.001). Conclusion: High cardiothoracic ratio and old age could independently predict a decline in nAb titers in an HD cohort vaccinated with a single dose of ChAdOx1.

scholarly journals Prediction of vaccine efficacy of the Delta variant

2021 ◽  
Author(s):  
Xinhua Chen ◽  
Andrew S. Azman ◽  
Wanying Lu ◽  
Ruijia Sun ◽  
Nan Zheng ◽  
...  
Keyword(s):  
Vaccine Efficacy ◽  
Protective Efficacy ◽  
Adenovirus Vector ◽  
Neutralizing Antibody ◽  
Effective Vaccine ◽  
Public Health Decision ◽  
Additional Tool ◽  
Health Decision Making ◽  
Health Decision ◽  
Antibody Titers

AbstractThe emergence of SARS-CoV-2 variants have raised concerns over the protective efficacy of the current generation of vaccines, and it remains unclear to what extent, if any, different variants impact the efficacy and effectiveness of various SARS-CoV-2 vaccines. We systematically searched for studies of SARS-CoV-2 vaccine efficacy and effectiveness, as well as neutralization data for variants, and used a previously published statistical model to predict vaccine efficacy against variants. Overall, we estimate the efficacy of mRNA-1273 and ChAdOx1 nCoV-19 against infection caused by the Delta variant to be 25-50% lower than that of prototype strains. The predicted efficacy against symptomatic illness of the mRNA vaccines BNT162b2 and mRNA-1273 are 95.1% (UI: 88.4-98.1%) and 80.8% (60.7-92.3%), respectively, which are higher than that of adenovirus-vector vaccines Ad26.COV2.S (44.8%, UI: 29.8-60.1%) and ChAdOx1 nCoV-19 (41.1%, 19.8-62.8%). Taken together, these results suggest that the development of more effective vaccine strategies against the Delta variant may be needed. Finally, the use of neutralizing antibody titers to predict efficacy against variants provides an additional tool for public health decision making, as new variants continue to emerge.

scholarly journals SARS-CoV-2 Convalescent Sera Binding and Neutralizing Antibody Concentrations Compared with COVID-19 Vaccine Efficacy Estimates Against Symptomatic Infection

2021 ◽  
Author(s):  
Amy J. Schuh ◽  
Panayampalli S. Satheshkumar ◽  
Stephanie Dietz ◽  
Lara Bull-Otterson ◽  
Myrna Charles ◽  
...  
Keyword(s):  
Vaccine Efficacy ◽  
Neutralizing Antibody ◽  
Published Data ◽  
Symptomatic Infection ◽  
Convenience Sample ◽  
Post Vaccination ◽  
Antibody Assays ◽  
Study Population ◽  
Binding Antibody ◽  
Induced Immunity

Previous vaccine efficacy (VE) studies have estimated neutralizing and binding antibody concentrations that correlate with protection from symptomatic infection; how these estimates compare to those generated in response to SARS-CoV-2 infection is unclear. Here, we assessed quantitative neutralizing and binding antibody concentrations using standardized SARS-CoV-2 assays on 3,067 serum specimens collected during July 27, 2020-August 27, 2020 from COVID-19 unvaccinated persons with detectable anti-SARS-CoV-2 antibodies using qualitative antibody assays. Quantitative neutralizing and binding antibody concentrations were strongly positively correlated (r=0.76, p<0.0001) and were noted to be several fold lower in the unvaccinated study population as compared to published data on concentrations noted 28 days post-vaccination. In this convenience sample, ~88% of neutralizing and ~63-86% of binding antibody concentrations met or exceeded concentrations associated with 70% COVID-19 VE against symptomatic infection from published VE studies; ~30% of neutralizing and 1-14% of binding antibody concentrations met or exceeded concentrations associated with 90% COVID-19 VE. These data support observations of infection-induced immunity and current recommendations for vaccination post infection to maximize protection against symptomatic COVID-19.

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