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1.
J Infect Dis ; 225(1): 34-41, 2022 01 05.
Article in English | MEDLINE | ID: covidwho-1605626

ABSTRACT

BACKGROUND: Vaccines that are shelf stable and easy to administer are crucial to improve vaccine access and reduce severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission around the world. METHODS: In this study, we demonstrate that an oral, adenovirus-based vaccine candidate protects against SARS-CoV-2 in a Syrian hamster challenge model. RESULTS: Hamsters administered 2 doses of VXA-CoV2-1 showed a reduction in weight loss and lung pathology and had completely eliminated infectious virus 5 days postchallenge. Oral immunization induced antispike immunoglobulin G, and neutralizing antibodies were induced upon oral immunization with the sera, demonstrating neutralizing activity. CONCLUSIONS: Overall, these data demonstrate the ability of oral vaccine candidate VXA-CoV2-1 to provide protection against SARS-CoV-2 disease.


Subject(s)
Adenovirus Vaccines/administration & dosage , COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , Mesocricetus , Adenovirus Vaccines/immunology , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/virology , COVID-19 Vaccines/immunology , Cricetinae , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Vaccination
2.
J Med Virol ; 93(12): 6486-6495, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1544303

ABSTRACT

OBJECTIVE: To systematically evaluate the effectiveness and safety of the SARS-CoV-2 vaccines currently undergoing clinical trials. METHODS: PubMed, EMBASE, and Cochrane Library databases were searched to collect open human COVID-19 vaccines randomized controlled trials, without limiting the search time and language. The research papers collected in the above-mentioned databases were initially screened according to the title and abstract content and merged, and the repeated ones were removed. After reading the full text of the remaining research, the studies that did not meet the inclusion criteria were excluded, and finally, nine studies were obtained. After extracting the statistical data of adverse events in the study, load them into Review Manager for heterogeneity analysis. RESULTS: The incidence of adverse reactions of inactivated virus vaccines, RNA vaccines, and adenovirus vector vaccines was higher than that of placebo. Common adverse reactions included pain, swelling, and fever at the injection site. CONCLUSION: From the perspective of effectiveness, RNA vaccine > adenovirus vector vaccine > inactivated virus vaccine. From the perspective of safety, the incidence of adverse reactions of the three vaccines is higher than that of a placebo, and the incidence of adverse reactions of the adenovirus vector vaccine is higher.


Subject(s)
COVID-19 Vaccines/adverse effects , COVID-19 Vaccines/immunology , COVID-19/prevention & control , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Adenovirus Vaccines/adverse effects , Adenovirus Vaccines/immunology , COVID-19 Vaccines/therapeutic use , Humans , Vaccination , Vaccines, Inactivated/adverse effects , Vaccines, Inactivated/immunology , Vaccines, Synthetic/adverse effects , Vaccines, Synthetic/immunology
3.
J Infect Dis ; 225(1): 34-41, 2022 01 05.
Article in English | MEDLINE | ID: covidwho-1510985

ABSTRACT

BACKGROUND: Vaccines that are shelf stable and easy to administer are crucial to improve vaccine access and reduce severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission around the world. METHODS: In this study, we demonstrate that an oral, adenovirus-based vaccine candidate protects against SARS-CoV-2 in a Syrian hamster challenge model. RESULTS: Hamsters administered 2 doses of VXA-CoV2-1 showed a reduction in weight loss and lung pathology and had completely eliminated infectious virus 5 days postchallenge. Oral immunization induced antispike immunoglobulin G, and neutralizing antibodies were induced upon oral immunization with the sera, demonstrating neutralizing activity. CONCLUSIONS: Overall, these data demonstrate the ability of oral vaccine candidate VXA-CoV2-1 to provide protection against SARS-CoV-2 disease.


Subject(s)
Adenovirus Vaccines/administration & dosage , COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , Mesocricetus , Adenovirus Vaccines/immunology , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/virology , COVID-19 Vaccines/immunology , Cricetinae , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Vaccination
4.
J Virol ; 95(23): e0097421, 2021 11 09.
Article in English | MEDLINE | ID: covidwho-1410203

ABSTRACT

The global COVID-19 pandemic has sparked intense interest in the rapid development of vaccines as well as animal models to evaluate vaccine candidates and to define immune correlates of protection. We recently reported a mouse-adapted SARS-CoV-2 virus strain (MA10) with the potential to infect wild-type laboratory mice, driving high levels of viral replication in respiratory tract tissues as well as severe clinical and respiratory symptoms, aspects of COVID-19 disease in humans that are important to capture in model systems. We evaluated the immunogenicity and protective efficacy of novel rhesus adenovirus serotype 52 (RhAd52) vaccines against MA10 challenge in mice. Baseline seroprevalence is lower for rhesus adenovirus vectors than for human or chimpanzee adenovirus vectors, making these vectors attractive candidates for vaccine development. We observed that RhAd52 vaccines elicited robust binding and neutralizing antibody titers, which inversely correlated with viral replication after challenge. These data support the development of RhAd52 vaccines and the use of the MA10 challenge virus to screen novel vaccine candidates and to study the immunologic mechanisms that underscore protection from SARS-CoV-2 challenge in wild-type mice. IMPORTANCE We have developed a series of SARS-CoV-2 vaccines using rhesus adenovirus serotype 52 (RhAd52) vectors, which exhibit a lower seroprevalence than human and chimpanzee vectors, supporting their development as novel vaccine vectors or as an alternative adenovirus (Ad) vector for boosting. We sought to test these vaccines using a recently reported mouse-adapted SARS-CoV-2 (MA10) virus to (i) evaluate the protective efficacy of RhAd52 vaccines and (ii) further characterize this mouse-adapted challenge model and probe immune correlates of protection. We demonstrate that RhAd52 vaccines elicit robust SARS-CoV-2-specific antibody responses and protect against clinical disease and viral replication in the lungs. Further, binding and neutralizing antibody titers correlated with protective efficacy. These data validate the MA10 mouse model as a useful tool to screen and study novel vaccine candidates, as well as the development of RhAd52 vaccines for COVID-19.


Subject(s)
Adenovirus Vaccines/immunology , Antibodies, Neutralizing/immunology , COVID-19 Vaccines/immunology , COVID-19/immunology , COVID-19/prevention & control , Pandemics/prevention & control , SARS-CoV-2/immunology , Adenoviridae Infections/immunology , Adenoviruses, Simian/immunology , Animals , Antibodies, Viral/immunology , Disease Models, Animal , Female , Humans , Immunogenicity, Vaccine , Macaca mulatta/virology , Mice , Mice, Inbred BALB C , SARS-CoV-2/pathogenicity , Vaccination
5.
Front Immunol ; 12: 697074, 2021.
Article in English | MEDLINE | ID: covidwho-1311376

ABSTRACT

The development of a safe and effective vaccine against SARS-CoV-2, the causative agent of pandemic coronavirus disease-2019 (COVID-19), is a global priority. Here, we aim to develop novel SARS-CoV-2 vaccines based on a derivative of less commonly used rare adenovirus serotype AdC68 vector. Three vaccine candidates were constructed expressing either the full-length spike (AdC68-19S) or receptor-binding domain (RBD) with two different signal sequences (AdC68-19RBD and AdC68-19RBDs). Single-dose intramuscular immunization induced robust and sustained binding and neutralizing antibody responses in BALB/c mice up to 40 weeks after immunization, with AdC68-19S being superior to AdC68-19RBD and AdC68-19RBDs. Importantly, immunization with AdC68-19S induced protective immunity against high-dose challenge with live SARS-CoV-2 in a golden Syrian hamster model of SARS-CoV-2 infection. Vaccinated animals demonstrated dramatic decreases in viral RNA copies and infectious virus in the lungs, as well as reduced lung pathology compared to the control animals. Similar protective effects were also found in rhesus macaques. Taken together, these results confirm that AdC68-19S can induce protective immune responses in experimental animals, meriting further development toward a human vaccine against SARS-CoV-2.


Subject(s)
Adenovirus Vaccines/administration & dosage , COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , Immunization Schedule , Immunogenicity, Vaccine , SARS-CoV-2/immunology , Vaccination/methods , Adenovirus Vaccines/immunology , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/virology , COVID-19 Vaccines/immunology , Cricetinae , Disease Models, Animal , Female , HEK293 Cells , Humans , Male , Mice , Mice, Inbred BALB C , Pan troglodytes , RNA, Viral/blood , Spike Glycoprotein, Coronavirus/immunology , Transfection , Treatment Outcome
6.
J Med Virol ; 93(12): 6486-6495, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1310532

ABSTRACT

OBJECTIVE: To systematically evaluate the effectiveness and safety of the SARS-CoV-2 vaccines currently undergoing clinical trials. METHODS: PubMed, EMBASE, and Cochrane Library databases were searched to collect open human COVID-19 vaccines randomized controlled trials, without limiting the search time and language. The research papers collected in the above-mentioned databases were initially screened according to the title and abstract content and merged, and the repeated ones were removed. After reading the full text of the remaining research, the studies that did not meet the inclusion criteria were excluded, and finally, nine studies were obtained. After extracting the statistical data of adverse events in the study, load them into Review Manager for heterogeneity analysis. RESULTS: The incidence of adverse reactions of inactivated virus vaccines, RNA vaccines, and adenovirus vector vaccines was higher than that of placebo. Common adverse reactions included pain, swelling, and fever at the injection site. CONCLUSION: From the perspective of effectiveness, RNA vaccine > adenovirus vector vaccine > inactivated virus vaccine. From the perspective of safety, the incidence of adverse reactions of the three vaccines is higher than that of a placebo, and the incidence of adverse reactions of the adenovirus vector vaccine is higher.


Subject(s)
COVID-19 Vaccines/adverse effects , COVID-19 Vaccines/immunology , COVID-19/prevention & control , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Adenovirus Vaccines/adverse effects , Adenovirus Vaccines/immunology , COVID-19 Vaccines/therapeutic use , Humans , Vaccination , Vaccines, Inactivated/adverse effects , Vaccines, Inactivated/immunology , Vaccines, Synthetic/adverse effects , Vaccines, Synthetic/immunology
7.
Mol Ther ; 29(8): 2412-2423, 2021 08 04.
Article in English | MEDLINE | ID: covidwho-1199134

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic caused by the emergent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) threatens global public health, and there is an urgent need to develop safe and effective vaccines. Here, we report the generation and the preclinical evaluation of a novel replication-defective gorilla adenovirus-vectored vaccine encoding the pre-fusion stabilized Spike (S) protein of SARS-CoV-2. We show that our vaccine candidate, GRAd-COV2, is highly immunogenic both in mice and macaques, eliciting both functional antibodies that neutralize SARS-CoV-2 infection and block Spike protein binding to the ACE2 receptor, and a robust, T helper (Th)1-dominated cellular response. We show here that the pre-fusion stabilized Spike antigen is superior to the wild type in inducing ACE2-interfering, SARS-CoV-2-neutralizing antibodies. To face the unprecedented need for vaccine manufacturing at a massive scale, different GRAd genome deletions were compared to select the vector backbone showing the highest productivity in stirred tank bioreactors. This preliminary dataset identified GRAd-COV2 as a potential COVID-19 vaccine candidate, supporting the translation of the GRAd-COV2 vaccine in a currently ongoing phase I clinical trial (ClinicalTrials.gov: NCT04528641).


Subject(s)
Adenoviridae/immunology , Adenovirus Vaccines/immunology , COVID-19 Vaccines/immunology , COVID-19/immunology , Gorilla gorilla/immunology , Immunogenicity, Vaccine/immunology , SARS-CoV-2/immunology , Adolescent , Adult , Aged , Aged, 80 and over , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Cell Line , Cell Line, Tumor , Female , Genetic Vectors/immunology , Gorilla gorilla/virology , HEK293 Cells , HeLa Cells , Humans , Macaca , Male , Mice , Mice, Inbred BALB C , Middle Aged , Pandemics/prevention & control , Young Adult
8.
Emerg Microbes Infect ; 10(1): 629-637, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1124369

ABSTRACT

COVID-19 vaccines emerging from different platforms differ in efficacy, duration of protection, and side effects. To maximize the benefits of vaccination, we explored the utility of employing a heterologous prime-boost strategy in which different combinations of the four types of leading COVID-19 vaccine candidates that are undergoing clinical trials in China were tested in a mouse model. Our results showed that sequential immunization with adenovirus vectored vaccine followed by inactivated/recombinant subunit/mRNA vaccine administration specifically increased levels of neutralizing antibodies and promoted the modulation of antibody responses to predominantly neutralizing antibodies. Moreover, a heterologous prime-boost regimen with an adenovirus vector vaccine also improved Th1-biased T cell responses. Our results provide new ideas for the development and application of COVID-19 vaccines to control the SARS-CoV-2 pandemic.


Subject(s)
Adenovirus Vaccines/immunology , Antibodies, Viral/blood , COVID-19 Vaccines/immunology , Immunization, Secondary/methods , Vaccines, Subunit/immunology , Vaccines, Synthetic/immunology , Adenovirus Vaccines/administration & dosage , Animals , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/prevention & control , COVID-19 Vaccines/adverse effects , Interferon-gamma/blood , Lymphocyte Count , Mice , Mice, Inbred BALB C , SARS-CoV-2/immunology , T-Lymphocytes/immunology , T-Lymphocytes, Helper-Inducer/immunology , Vaccination/adverse effects , Vaccines, Subunit/administration & dosage , Vaccines, Synthetic/administration & dosage
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