scholarly journals Comparison of Neutralizing Antibody Titers Elicited by mRNA and Adenoviral Vector Vaccine against SARS-CoV-2 Variants

2021 ◽  
Author(s):  
Takuya Tada ◽  
Hao Zhou ◽  
Marie I Samanovic ◽  
Belinda M Dcosta ◽  
Amber Cornelius ◽  
...  
Keyword(s):  
Vaccine Efficacy ◽  
Adenoviral Vector ◽  
Neutralizing Antibody ◽  
Significant Fraction ◽  
Vector Vaccine ◽  
Antibody Titers

The increasing prevalence of SARS-CoV-2 variants has raised concerns regarding possible decreases in vaccine efficacy. Here, neutralizing antibody titers elicited by mRNA-based and an adenoviral vector-based vaccine against variant pseudotyped viruses were compared. BNT162b2 and mRNA-1273-elicited antibodies showed modest neutralization resistance against Beta, Delta, Delta plus and Lambda variants whereas Ad26.COV2.S-elicited antibodies from a significant fraction of vaccinated individuals were of low neutralizing titer (IC50 <50). The data underscore the importance of surveillance for breakthrough infections that result in severe COVID-19 and suggest the benefit of a second immunization following Ad26.COV2.S to increase protection against the variants.

scholarly journals Safety and immunogenicity of a heterologous booster of protein subunit vaccine MVC-COV1901 after two doses of adenoviral vector vaccine AZD1222

2021 ◽  
Author(s):  
Shu-Hsing Cheng ◽  
Yi-Chun Lin ◽  
Cheng-Pin Chen ◽  
Chien-Yu Cheng
Keyword(s):  
Adenoviral Vector ◽  
Subunit Vaccine ◽  
Booster Dose ◽  
Neutralizing Antibody ◽  
Protein Subunit ◽  
Igg Antibody ◽  
Vector Vaccine ◽  
Antibody Titers

We report the interim safety and immunogenicity results in participants administrated with a booster dose of protein subunit vaccine MVC-COV1901 at 12 or 24 weeks after two doses of AZD1222 (ChAdOx1 nCoV-19). In subjects fully vaccinated with two doses of AZD1222, waning antibody immunity was apparent within six months of the second dose of AZD1222. At one month after the MVC-COV1901 booster dose, anti-SARS-CoV-2 spike IgG antibody titers and neutralizing antibody titers were 14- and 8.6-fold increased, respectively, when compared to the titer levels on the day of the booster dose. These interim results support the use of MVC-COV1901 as a heterologous booster for individuals vaccinated with AZD1222.

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 Protective Efficacy of Recombinant Influenza Hemagglutinin Ectodomain Fusions

Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1710
Author(s):  
Nidhi Mittal ◽  
Nayanika Sengupta ◽  
Sameer Kumar Malladi ◽  
Poorvi Reddy ◽  
Madhuraj Bhat ◽  
...  
Keyword(s):  
Vaccine Efficacy ◽  
Influenza A ◽  
Protective Efficacy ◽  
Neutralizing Antibody ◽  
Surface Proteins ◽  
Influenza Vaccines ◽  
High Yield ◽  
Suspension Cells ◽  
Water Emulsion ◽  
Antibody Titers

In current seasonal influenza vaccines, neutralizing antibody titers directed against the hemagglutinin surface protein are the primary correlate of protection. These vaccines are, therefore, quantitated in terms of their hemagglutinin content. Adding other influenza surface proteins, such as neuraminidase and M2e, to current quadrivalent influenza vaccines would likely enhance vaccine efficacy. However, this would come with increased manufacturing complexity and cost. To address this issue, as a proof of principle, we have designed genetic fusions of hemagglutinin ectodomains from H3 and H1 influenza A subtypes. These recombinant H1-H3 hemagglutinin ectodomain fusions could be transiently expressed at high yield in mammalian cell culture using Expi293F suspension cells. Fusions were trimeric, and as stable in solution as their individual trimeric counterparts. Furthermore, the H1-H3 fusion constructs were antigenically intact based on their reactivity with a set of conformation-specific monoclonal antibodies. H1-H3 hemagglutinin ectodomain fusion immunogens, when formulated with the MF59 equivalent adjuvant squalene-in-water emulsion (SWE), induced H1 and H3-specific humoral immune responses equivalent to those induced with an equimolar mixture of individually expressed H1 and H3 ectodomains. Mice immunized with these ectodomain fusions were protected against challenge with heterologous H1N1 (Bel/09) and H3N2 (X-31) mouse-adapted viruses with higher neutralizing antibody titers against the H1N1 virus. Use of such ectodomain-fused immunogens would reduce the number of components in a vaccine formulation and allow for the inclusion of other protective antigens to increase influenza vaccine efficacy.

OR23 HLA class II genes correlate with protective neutralizing antibody titers in a dengue vaccine efficacy trial

2018 ◽  
Vol 79 ◽  
pp. 29
Author(s):  
Aviva Geretz ◽  
Shida Shangguan ◽  
Chris Bryant ◽  
Philip Ehrenberg ◽  
Merlin Robb ◽  
...  
Keyword(s):  
Vaccine Efficacy ◽  
Neutralizing Antibody ◽  
Class Ii ◽  
Hla Class Ii ◽  
Efficacy Trial ◽  
Dengue Vaccine ◽  
Antibody Titers

Presence of antibody in virus-infected brain cells of SSPE ferrets

1983 ◽  
Vol 41 ◽  
pp. 804-805
Author(s):  
Hannah R. Brown ◽  
Tammy L. Donato ◽  
Halldor Thormar
Keyword(s):  
Measles Virus ◽  
Plasma Cells ◽  
Subacute Sclerosing Panencephalitis ◽  
Protein A ◽  
Neutralizing Antibody ◽  
Brain Cells ◽  
Antibody Titers ◽  
A Cell ◽  
The Central Nervous System ◽  
The Brain

Measles virus specific immunoglobulin G (IgG) has been found in the brains of patients with subacute sclerosing panencephalitis (SSPE), a slowly progressing disease of the central nervous system (CNS) in children. IgG/albumin ratios indicate that the antibodies are synthesized within the CNS. Using the ferret as an animal model to study the disease, we have been attempting to localize the Ig's in the brains of animals inoculated with a cell associated strain of SSPE. In an earlier report, preliminary results using Protein A conjugated to horseradish peroxidase (PrAPx) (Dynatech Diagnostics Inc., South Windham, ME.) to detect antibodies revealed the presence of immunoglobulin mainly in antibody-producing plasma cells in inflammatory lesions and not in infected brain cells.In the present experiment we studied the brain of an SSPE ferret with neutralizing antibody titers of 1:1024 in serum and 1:512 in CSF at time of sacrifice 7 months after i.c. inoculation with SSPE measles virus-infected cells. The animal was perfused with saline and portions of the brain and spinal cord were immersed in periodate-lysine-paraformaldehyde (P-L-P) fixative. The ferret was not perfused with fixative because parts of the brain were used for virus isolation.

scholarly journals Convalescent Plasma Efficacy in Life-Threatening COVID-19 Patients Admitted to the ICU: A Retrospective Cohort Study

2021 ◽  
Vol 10 (10) ◽  
pp. 2113
Author(s):  
Mohamed Abuzakouk ◽  
Khaled Saleh ◽  
Manuel Algora ◽  
Ahmad Nusair ◽  
Jawahir Alameri ◽  
...  
Keyword(s):  
Hospital Mortality ◽  
Clinical Improvement ◽  
Primary Outcome ◽  
Neutralizing Antibody ◽  
Limited Data ◽  
Inverse Probability Weights ◽  
Single Center Study ◽  
Life Threatening ◽  
Antibody Titers ◽  
Disease Severity Scale

(1) Background: There are limited data regarding the efficacy of convalescent plasma (CP) in critically ill patients admitted to the intensive care unit (ICU) due to coronavirus disease 2019 (COVID-19). We aimed to determine whether CP is associated with better clinical outcome among these patients. (2) Methods: A retrospective single-center study including adult patients with laboratory-confirmed SARS-CoV-2 infection admitted to the ICU for acute respiratory failure. The primary outcome was time to clinical improvement, within 28 days, defined as patient discharged alive or reduction of 2 points on a 6-point disease severity scale. (3) Results: Overall, 110 COVID-19 patients were admitted. Thirty-two patients (29%) received CP; among them, 62.5% received at least one CP with high neutralizing antibody titers (≥1:160). Clinical improvement occurred within 28 days in 14 patients (43.7%) of the CP group vs. 48 patients (61.5%) in the non-CP group (hazard ratio (HR): 0.75 (95% CI: 0.41–1.37), p = 0.35). After adjusting for potential confounding factors, CP was not independently associated with time to clinical improvement (HR: 0.53 (95% CI: 0.23–1.22), p = 0.14). Additionally, the average treatment effects of CP, calculated using the inverse probability weights (IPW), was not associated with the primary outcome (−0.14 days (95% CI: −3.19–2.91 days), p = 0.93). Hospital mortality did not differ between CP and non-CP groups (31.2% vs. 19.2%, p = 0.17, respectively). Comparing CP with high neutralizing antibody titers to the other group yielded the same findings. (4) Conclusions: In this study of life-threatening COVID-19 patients, CP was not associated with time to clinical improvement within 28 days, or hospital mortality.

scholarly journals Serum Neutralizing Activity against B.1.1.7, B.1.351, and P.1 SARS-CoV-2 Variants of Concern in Hospitalized COVID-19 Patients

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1347
Author(s):  
Claudia Maria Trombetta ◽  
Serena Marchi ◽  
Simonetta Viviani ◽  
Alessandro Manenti ◽  
Linda Benincasa ◽  
...  
Keyword(s):  
Natural Infection ◽  
Neutralizing Antibody ◽  
Original Strain ◽  
Immune Protection ◽  
Serum Samples ◽  
Symptomatic Infection ◽  
Neutralizing Activity ◽  
The United Kingdom ◽  
Antibody Titers ◽  
Pandemic Wave

The recent spreading of new SARS-CoV-2 variants, carrying several mutations in the spike protein, could impact immune protection elicited by natural infection or conferred by vaccination. In this study, we evaluated the neutralizing activity against the viral variants that emerged in the United Kingdom (B.1.1.7), Brazil (P.1), and South Africa (B.1.351) in human serum samples from hospitalized patients infected by SARS-CoV-2 during the first pandemic wave in Italy in 2020. Of the patients studied, 59.5% showed a decrease (≥2 fold) in neutralizing antibody titer against B.1.1.7, 83.3% against P.1, and 90.5% against B.1.351 with respect to the original strain. The reduction in antibody titers against all analyzed variants, and in particular P.1 and B.1.351, suggests that previous symptomatic infection might be not fully protective against exposure to SARS-CoV-2 variants carrying a set of relevant spike mutations.

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