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2.
Cell ; 185(5): 896-915.e19, 2022 03 03.
Article in English | MEDLINE | ID: covidwho-1670278

ABSTRACT

The emerging SARS-CoV-2 variants of concern (VOCs) threaten the effectiveness of current COVID-19 vaccines administered intramuscularly and designed to only target the spike protein. There is a pressing need to develop next-generation vaccine strategies for broader and long-lasting protection. Using adenoviral vectors (Ad) of human and chimpanzee origin, we evaluated Ad-vectored trivalent COVID-19 vaccines expressing spike-1, nucleocapsid, and RdRp antigens in murine models. We show that single-dose intranasal immunization, particularly with chimpanzee Ad-vectored vaccine, is superior to intramuscular immunization in induction of the tripartite protective immunity consisting of local and systemic antibody responses, mucosal tissue-resident memory T cells and mucosal trained innate immunity. We further show that intranasal immunization provides protection against both the ancestral SARS-CoV-2 and two VOC, B.1.1.7 and B.1.351. Our findings indicate that respiratory mucosal delivery of Ad-vectored multivalent vaccine represents an effective next-generation COVID-19 vaccine strategy to induce all-around mucosal immunity against current and future VOC.


Subject(s)
COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , Immunity, Mucosal , Administration, Intranasal , Animals , Antibodies, Viral/blood , Antibodies, Viral/immunology , B-Lymphocytes/immunology , B-Lymphocytes/metabolism , COVID-19/virology , COVID-19 Vaccines/immunology , Cytokines/blood , Genetic Vectors/genetics , Genetic Vectors/immunology , Genetic Vectors/metabolism , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Neutralization Tests , Nucleocapsid/genetics , Nucleocapsid/immunology , Nucleocapsid/metabolism , Pan troglodytes , SARS-CoV-2/genetics , SARS-CoV-2/immunology , SARS-CoV-2/isolation & purification , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism , T-Lymphocytes/immunology , T-Lymphocytes/metabolism
3.
2021.
Preprint in English | Other preprints | ID: ppcovidwho-294322

ABSTRACT

Nursing home residents often fail to mount robust responses to vaccinations and recent reports of breakthrough infections, particularly from variants of concern, raise questions about whether vaccination regimens elicit a sufficient humoral immune response or if booster doses are warranted. We examined SARS-CoV-2 antibody levels and neutralizing capacity in nursing home residents 3-5 months after 2 doses of mRNA-1273 or BNT163b2 vaccination as per recommended schedules. Nursing home residents were recruited from eight long-term care homes in Ontario, Canada, between March and July 2021. Antibody levels and neutralization capacity from a previously published convalescent cohort were used as a comparator. Serum SARS-CoV-2 IgA/G/M against spike (S) protein and its receptor-binding domain (RBD) were measured by validated ELISA, with assay cut-off at the mean and 3 standard deviations of a pre-COVID-19 population from the same geographic region. Antibody neutralization was measured against the wild-type strain of SARS-CoV-2 and the beta variant of concern (B.1.351). No neutralizing antibodies were detected in ∼20% of residents to the wild-type virus (30/155;19%) or beta variant (27/134;20%). Residents that received BNT163b2 had a ∼4-fold reduction in neutralization to the wild-type strain, and a ∼2-fold reduction in neutralization to the beta variant relative to those who received mRNA-1273. Current mRNA SARS-CoV-2 vaccine regimens may not have equivalent efficacy in nursing home residents. Our findings imply that differences in the humoral immune response may contribute to breakthrough infections, and suggest that consideration of the type of vaccine administered to older adults will have a positive impact on the generation of protective immunity.

4.
Discrete Dynamics in Nature and Society ; 2021, 2021.
Article in English | ProQuest Central | ID: covidwho-1546602

ABSTRACT

In this study, we formulate a noninteger-order mathematical model via the Caputo operator for the transmission dynamics of the bacterial disease tuberculosis (TB) in Khyber Pakhtunkhwa (KP), Pakistan. The number of confirmed cases from 2002 to 2017 is considered as incidence data for the estimation of parameters or to parameterize the model and analysis. The positivity and boundedness of the model solution are derived. For the dynamics of the tuberculosis model, we find the equilibrium points and the basic reproduction number. The proposed model is locally and globally stable at disease-free equilibrium, if the reproduction number ℛ0<1. Furthermore, to examine the behavior of the various parameters and different values of fractional-order derivative graphically, the most common iterative scheme based on fundamental theorem and Lagrange interpolation polynomial is implemented. From the numerical result, it is observed that the contact rate and treatment rate have a great impact on curtailing the tuberculosis disease. Furthermore, proper treatment is a key factor in reducing the TB transmission and prevalence. Also, the results are more precise for lower fractional order. The results from various numerical plots show that the fractional model gives more insights into the disease dynamics and on how to curtail the disease spread.

6.
Viruses ; 13(4)2021 04 16.
Article in English | MEDLINE | ID: covidwho-1194709

ABSTRACT

Coronavirus Disease 2019 (COVID-19) is a global pandemic caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While detection of SARS-CoV-2 by polymerase chain reaction with reverse transcription (RT-PCR) is currently used to diagnose acute COVID-19 infection, serological assays are needed to study the humoral immune response to SARS-CoV-2. Anti-SARS-CoV-2 immunoglobulin (Ig)G/A/M antibodies against spike (S) protein and its receptor-binding domain (RBD) were characterized in recovered subjects who were RT-PCR-positive (n = 153) and RT-PCR-negative (n = 55) using an enzyme-linked immunosorbent assay (ELISA). These antibodies were also further assessed for their ability to neutralize live SARS-CoV-2 virus. Anti-SARS-CoV-2 antibodies were detected in 90.9% of resolved subjects up to 180 days post-symptom onset. Anti-S protein and anti-RBD IgG titers correlated (r = 0.5157 and r = 0.6010, respectively) with viral neutralization. Of the RT-PCR-positive subjects, 22 (14.3%) did not have anti-SARS-CoV-2 antibodies; and of those, 17 had RT-PCR cycle threshold (Ct) values > 27. These high Ct values raise the possibility that these indeterminate results are from individuals who were not infected or had mild infection that failed to elicit an antibody response. This study highlights the importance of serological surveys to determine population-level immunity based on infection numbers as determined by RT-PCR.


Subject(s)
Antibodies, Viral/immunology , COVID-19/immunology , SARS-CoV-2/immunology , Adolescent , Adult , Aged , Aged, 80 and over , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/immunology , Antibodies, Viral/blood , COVID-19/blood , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19 Nucleic Acid Testing , COVID-19 Serological Testing , Female , Humans , Immunoglobulin Isotypes/blood , Immunoglobulin Isotypes/immunology , Male , Middle Aged , Spike Glycoprotein, Coronavirus/immunology , Young Adult
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