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2.
Proc Natl Acad Sci U S A ; 119(35): e2110105119, 2022 08 30.
Article in English | MEDLINE | ID: covidwho-2000999

ABSTRACT

The spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the main target for neutralizing antibodies (NAbs). The S protein trimer is anchored in the virion membrane in its prefusion (preS) but metastable form. The preS protein has been stabilized by introducing two or six proline substitutions, to generate stabilized, soluble 2P or HexaPro (6P) preS proteins. Currently, it is not known which form is the most immunogenic. Here, we generated recombinant vesicular stomatitis virus (rVSV) expressing preS-2P, preS-HexaPro, and native full-length S, and compared their immunogenicity in mice and hamsters. The rVSV-preS-HexaPro produced and secreted significantly more preS protein compared to rVSV-preS-2P. Importantly, rVSV-preS-HexaPro triggered significantly more preS-specific serum IgG antibody than rVSV-preS-2P in both mice and hamsters. Antibodies induced by preS-HexaPro neutralized the B.1.1.7, B.1.351, P.1, B.1.427, and B.1.617.2 variants approximately two to four times better than those induced by preS-2P. Furthermore, preS-HexaPro induced a more robust Th1-biased cellular immune response than preS-2P. A single dose (104 pfu) immunization with rVSV-preS-HexaPro and rVSV-preS-2P provided complete protection against challenge with mouse-adapted SARS-CoV-2 and B.1.617.2 variant, whereas rVSV-S only conferred partial protection. When the immunization dose was lowered to 103 pfu, rVSV-preS-HexaPro induced two- to sixfold higher antibody responses than rVSV-preS-2P in hamsters. In addition, rVSV-preS-HexaPro conferred 70% protection against lung infection whereas only 30% protection was observed in the rVSV-preS-2P. Collectively, our data demonstrate that both preS-2P and preS-HexaPro are highly efficacious but preS-HexaPro is more immunogenic and protective, highlighting the advantages of using preS-HexaPro in the next generation of SARS-CoV-2 vaccines.


Subject(s)
Proline , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Vaccine Development , Vesicular Stomatitis , Viral Vaccines , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/genetics , COVID-19/immunology , COVID-19/prevention & control , COVID-19/virology , COVID-19 Vaccines/immunology , Cricetinae , Humans , Mice , Proline/immunology , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Vesicular Stomatitis/immunology , Vesicular Stomatitis/prevention & control , Vesicular Stomatitis/virology , Vesiculovirus/immunology , Viral Proteins/immunology , Viral Vaccines/immunology
3.
Viruses ; 12(1)2020 01 20.
Article in English | MEDLINE | ID: covidwho-1969491

ABSTRACT

Middle East respiratory syndrome (MERS) is an acute, high-mortality-rate, severe infectious disease caused by an emerging MERS coronavirus (MERS-CoV) that causes severe respiratory diseases. The continuous spread and great pandemic potential of MERS-CoV make it necessarily important to develop effective vaccines. We previously demonstrated that the application of Gram-positive enhancer matrix (GEM) particles as a bacterial vector displaying the MERS-CoV receptor-binding domain (RBD) is a very promising MERS vaccine candidate that is capable of producing potential neutralization antibodies. We have also used the rabies virus (RV) as a viral vector to design a recombinant vaccine by expressing the MERS-CoV S1 (spike) protein on the surface of the RV. In this study, we compared the immunological efficacy of the vaccine candidates in BALB/c mice in terms of the levels of humoral and cellular immune responses. The results show that the rabies virus vector-based vaccine can induce remarkably earlier antibody response and higher levels of cellular immunity than the GEM particles vector. However, the GEM particles vector-based vaccine candidate can induce remarkably higher antibody response, even at a very low dose of 1 µg. These results indicate that vaccines constructed using different vaccine vector platforms for the same pathogen have different rates and trends in humoral and cellular immune responses in the same animal model. This discovery not only provides more alternative vaccine development platforms for MERS-CoV vaccine development, but also provides a theoretical basis for our future selection of vaccine vector platforms for other specific pathogens.


Subject(s)
Coronavirus Infections/immunology , Middle East Respiratory Syndrome Coronavirus/immunology , Viral Vaccines/immunology , Animals , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/immunology , Antibodies, Viral/blood , Antibodies, Viral/immunology , Cell Line , Coronavirus Infections/prevention & control , Genetic Vectors , Humans , Immunization , Immunoglobulin G/blood , Immunoglobulin G/immunology , Lactococcus lactis/genetics , Mice , Mice, Inbred BALB C , Middle East Respiratory Syndrome Coronavirus/genetics , Rabies virus/genetics , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , T-Lymphocytes/immunology , Vaccines, Synthetic/administration & dosage , Vaccines, Synthetic/immunology , Viral Vaccines/administration & dosage
4.
J Virol ; 96(13): e0014322, 2022 Jul 13.
Article in English | MEDLINE | ID: covidwho-1879115

ABSTRACT

Differentiation of infected from vaccinated hosts (DIVH) is a critical step in virus eradication programs. DIVH-compatible vaccines, however, take years to develop, and are therefore unavailable for fighting the sudden outbreaks that typically drive pandemics. Here, we establish a protocol for the swift and efficient development of DIVH assays, and show that this approach is compatible with any type of vaccines. Using porcine circovirus 2 (PCV2) as the experimental model, the first step is to use Immunoglobin G (IgG) sero-dynamics (IsD) curves to aid epitope discovery (IsDAED): PCV2 Cap peptides were categorized into three types: null interaction, nonspecific interaction (NSI), and specific interaction (SI). We subsequently compared IsDAED approach and traditional approach, and demonstrated identifying SI peptides and excluding NSI peptides supports efficient diagnostic kit development, specifically using a protein-peptide hybrid microarray (PPHM). IsDAED directed the design of a DIVH protocol for three types of PCV2 vaccines (while using a single PPHM). Finally, the DIVH protocol successfully differentiated infected pigs from vaccinated pigs at five farms. This IsDAED approach is almost certainly extendable to other viruses and host species. IMPORTANCE Sudden outbreaks of pandemics caused by virus, such as SARS-CoV-2, has been determined as a public health emergency of international concern. However, the development of a DIVH-compatible vaccine is time-consuming and full of uncertainty, which is unsuitable for an emergent situation like the ongoing COVID-19 pandemic. Along with the development and public health implementation of new vaccines to prevent human diseases, e.g., human papillomavirus vaccines for cervical cancer; enterovirus 71 vaccines for hand, foot, and mouth disease; and most recently SARS-CoV-2, there is an increasing demand for DIVH. Here, we use the IsDAED approach to confirm SI peptides and to exclude NSI peptides, finally to direct the design of a DIVH protocol. It is plausible that our IsDAED approach is applicable for other infectious disease.


Subject(s)
Antibodies, Viral , Circoviridae Infections , Epitopes , Immunoglobulin G , Viral Vaccines , Animals , Antibodies, Viral/blood , COVID-19 , Circoviridae Infections/immunology , Circovirus , Disease Models, Animal , Epitopes/analysis , Epitopes/immunology , Humans , Immunoglobulin G/blood , Immunoglobulin G/immunology , Peptides , SARS-CoV-2 , Swine , Swine Diseases/immunology , Viral Vaccines/immunology
5.
N Engl J Med ; 386(23): 2201-2212, 2022 06 09.
Article in English | MEDLINE | ID: covidwho-1864786

ABSTRACT

BACKGROUND: Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) provides natural immunity against reinfection. Recent studies have shown waning of the immunity provided by the BNT162b2 vaccine. The time course of natural and hybrid immunity is unknown. METHODS: Using the Israeli Ministry of Health database, we extracted data for August and September 2021, when the B.1.617.2 (delta) variant was predominant, on all persons who had been previously infected with SARS-CoV-2 or who had received coronavirus 2019 vaccine. We used Poisson regression with adjustment for confounding factors to compare the rates of infection as a function of time since the last immunity-conferring event. RESULTS: The number of cases of SARS-CoV-2 infection per 100,000 person-days at risk (adjusted rate) increased with the time that had elapsed since vaccination with BNT162b2 or since previous infection. Among unvaccinated persons who had recovered from infection, this rate increased from 10.5 among those who had been infected 4 to less than 6 months previously to 30.2 among those who had been infected 1 year or more previously. Among persons who had received a single dose of vaccine after previous infection, the adjusted rate was low (3.7) among those who had been vaccinated less than 2 months previously but increased to 11.6 among those who had been vaccinated at least 6 months previously. Among previously uninfected persons who had received two doses of vaccine, the adjusted rate increased from 21.1 among those who had been vaccinated less than 2 months previously to 88.9 among those who had been vaccinated at least 6 months previously. CONCLUSIONS: Among persons who had been previously infected with SARS-CoV-2 (regardless of whether they had received any dose of vaccine or whether they had received one dose before or after infection), protection against reinfection decreased as the time increased since the last immunity-conferring event; however, this protection was higher than that conferred after the same time had elapsed since receipt of a second dose of vaccine among previously uninfected persons. A single dose of vaccine after infection reinforced protection against reinfection.


Subject(s)
COVID-19 , BNT162 Vaccine/immunology , BNT162 Vaccine/therapeutic use , COVID-19/epidemiology , COVID-19/immunology , COVID-19/prevention & control , COVID-19 Vaccines/immunology , COVID-19 Vaccines/therapeutic use , Humans , Immunity, Innate , Reinfection/immunology , Reinfection/prevention & control , SARS-CoV-2 , Time Factors , Viral Vaccines/immunology , Viral Vaccines/therapeutic use
6.
Curr Opin Immunol ; 77: 102209, 2022 08.
Article in English | MEDLINE | ID: covidwho-1857941

ABSTRACT

Viral proteins fold into a variety of structures as they perform their functions. Structure-based vaccine design aims to exploit knowledge of an antigen's architecture to stabilize it in a vulnerable conformation. We summarize the general principles of structure-based vaccine design, with a focus on the major types of sequence modifications: proline, disulfide, cavity-filling, electrostatic and hydrogen-bond substitution, as well as domain deletion. We then review recent applications of these principles to vaccine-design efforts across five viral families: Coronaviridae, Orthomyxoviridae, Paramyxoviridae, Pneumoviridae, and Filoviridae. Outstanding challenges include continued application of proven design principles to pathogens of interest, as well as development of new strategies for those pathogens that resist traditional techniques.


Subject(s)
Vaccine Development , Viral Proteins , Viral Vaccines , Coronaviridae , Filoviridae , Humans , Orthomyxoviridae , Paramyxoviridae , Pneumovirinae , Viral Proteins/immunology , Viral Vaccines/immunology
7.
Med Sci Monit ; 28: e935879, 2022 Mar 21.
Article in English | MEDLINE | ID: covidwho-1753960

ABSTRACT

According to world statistics, men are more susceptible to the coronavirus disease 2019 (COVID-19) than are women. Considering the interconnection between infections and male infertility, investigation of the potential impact of COVID-19 on men's reproductive health is now a particularly relevant topic. Published data indicate decreased sperm quality and orchitis development in patients with COVID-19, including reduced sperm count, decreased sperm motility, and elevated DNA fragmentation index. Although mass vaccination against COVID-19 is currently being carried out worldwide using available authorized vaccines, the effect of these vaccines on men's reproductive health has not yet been investigated. There is currently no evidence that SARS-CoV-2 can be transmitted in semen, but available data suggest that it can infect spermatogonia, spermatids, Leydig cells, and Sertoli cells. Therefore, SARS-CoV-2 orchitis and reduced male fertility may be long-term complications of COVID-19, which requires further investigation. Currently, there is also no evidence that vaccines against SARS-CoV-2 have any pathological effects on spermatogenesis or male reproductive health. Thus, further studies are needed to determine the effects of COVID-19 and COVID-19 vaccines on men's reproductive health, which will help to optimize the management and rehabilitation of these patients. This review aims to discuss recent studies on the impact of the COVID-19 and COVID-19 vaccines on men's reproductive health. The article addresses various issues such as the effect of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on testosterone biosynthesis, semen parameters, testicular tissue, and epididymis.


Subject(s)
COVID-19 Vaccines/adverse effects , COVID-19/immunology , Sperm Motility/drug effects , COVID-19 Vaccines/immunology , Humans , Male , Reproductive Health/trends , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Sperm Motility/physiology , Viral Vaccines/immunology
8.
Proc Natl Acad Sci U S A ; 119(14): e2119093119, 2022 04 05.
Article in English | MEDLINE | ID: covidwho-1751830

ABSTRACT

SignificanceUsing SARS-CoV-2 as a relevant case study for infectious disease, we investigate the structure-function relationships that dictate antiviral spherical nucleic acid (SNA) vaccine efficacy. We show that the SNA architecture can be rapidly employed to target COVID-19 through incorporation of the receptor-binding domain, and that the resulting vaccine potently activates human cells in vitro and mice in vivo. Furthermore, when challenged with a lethal viral infection, only mice treated with the SNA vaccine survived. Taken together, this work underscores the importance of rational vaccine design for infectious disease to yield vaccines that elicit more potent immune responses to effectively fight disease.


Subject(s)
Communicable Disease Control , Nucleic Acids/immunology , Vaccines, DNA/immunology , Animals , Biotechnology , COVID-19/prevention & control , Communicable Disease Control/methods , Communicable Diseases/etiology , Communicable Diseases/immunology , Humans , Nucleic Acids/chemistry , SARS-CoV-2/immunology , Vaccine Development , Vaccines, DNA/genetics , Viral Vaccines/genetics , Viral Vaccines/immunology
9.
Proc Natl Acad Sci U S A ; 119(12): e2200065119, 2022 03 22.
Article in English | MEDLINE | ID: covidwho-1740535

ABSTRACT

SignificanceConcern has increased about the pandemic potential of Nipah virus (NiV). Similar to SARS-CoV-2, NiV is an RNA virus that is transmitted by respiratory droplets. There are currently no NiV vaccines licensed for human use. While several preventive vaccines have shown promise in protecting animals against lethal NiV disease, most studies have assessed protection 1 mo after vaccination. However, in order to contain and control outbreaks, vaccines that can rapidly confer protection in days rather than months are needed. Here, we show that a recombinant vesicular stomatitis virus vector expressing the NiV glycoprotein can completely protect monkeys vaccinated 7 d prior to NiV exposure and 67% of animals vaccinated 3 d before NiV challenge.


Subject(s)
Henipavirus Infections/veterinary , Nipah Virus/immunology , Primate Diseases/prevention & control , Vaccines, Synthetic/immunology , Viral Vaccines/immunology , Animals , Antibodies, Neutralizing , Antibodies, Viral/immunology , Biomarkers , Genetic Vectors , Kaplan-Meier Estimate , Neutralization Tests , Outcome Assessment, Health Care , Primate Diseases/diagnosis , Primate Diseases/mortality , Primate Diseases/virology , Vaccination , Viral Load
10.
Science ; 375(6585): 1133-1139, 2022 Mar 11.
Article in English | MEDLINE | ID: covidwho-1736002

ABSTRACT

The vaccine and drug discovery responses to COVID-19 have worked far better than could have been imagined. Yet by the end of 2021, more than 5 million people had died, and the pandemic continues to evolve and rage globally. This Review will describe how each of the vaccines, antibody therapies, and antiviral drugs that have been approved to date were built on decades of investment in technology and basic science. We will caution that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has so far proven a straightforward test of our pandemic preparedness, and we will recommend steps we should undertake now to prepare for, to minimize the effects of, and ideally to prevent future pandemics. Other Reviews in this series describe the interactions of SARS-CoV-2 with the immune system and those therapies that target the host response to infection.


Subject(s)
Antiviral Agents/therapeutic use , COVID-19 Vaccines , COVID-19/drug therapy , COVID-19/prevention & control , Pandemics/prevention & control , SARS-CoV-2/immunology , Antibodies, Monoclonal/therapeutic use , COVID-19/virology , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/immunology , Disease Progression , Drug Development , Drug Discovery , Humans , SARS-CoV-2/drug effects , Vaccinology , Viral Vaccines/immunology , Virus Diseases/drug therapy , Virus Diseases/prevention & control
11.
Viruses ; 12(5)2020 05 10.
Article in English | MEDLINE | ID: covidwho-1726011

ABSTRACT

The COVID-19 pandemic is due to infection caused by the novel SARS-CoV-2 virus that impacts the lower respiratory tract. The spectrum of symptoms ranges from asymptomatic infections to mild respiratory symptoms to the lethal form of COVID-19 which is associated with severe pneumonia, acute respiratory distress, and fatality. To address this global crisis, up-to-date information on viral genomics and transcriptomics is crucial for understanding the origins and global dispersion of the virus, providing insights into viral pathogenicity, transmission, and epidemiology, and enabling strategies for therapeutic interventions, drug discovery, and vaccine development. Therefore, this review provides a comprehensive overview of COVID-19 epidemiology, genomic etiology, findings from recent transcriptomic map analysis, viral-human protein interactions, molecular diagnostics, and the current status of vaccine and novel therapeutic intervention development. Moreover, we provide an extensive list of resources that will help the scientific community access numerous types of databases related to SARS-CoV-2 OMICs and approaches to therapeutics related to COVID-19 treatment.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/epidemiology , Coronavirus Infections/therapy , Pneumonia, Viral/epidemiology , Pneumonia, Viral/therapy , COVID-19 , COVID-19 Vaccines , Coronavirus Infections/drug therapy , Coronavirus Infections/genetics , Coronavirus Infections/immunology , Coronavirus Infections/prevention & control , Genomics , Humans , Pandemics , Pneumonia, Viral/genetics , Pneumonia, Viral/immunology , SARS-CoV-2 , Viral Vaccines/immunology
13.
Viruses ; 14(2)2022 02 12.
Article in English | MEDLINE | ID: covidwho-1687051

ABSTRACT

The persistent expansion of the coronavirus disease 2019 (COVID-19) global pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) requires the rapid development of safe and effective countermeasures to reduce transmission, morbidity, and mortality. Several highly efficacious vaccines are actively being deployed around the globe to expedite mass vaccination and control of COVID-19. Notably, viral vectored vaccines (VVVs) are among the first to be approved for global distribution and use. In this review, we examine the humoral, cellular, and innate immune responses elicited by viral vectors, and the immune correlates of protection against COVID-19 in preclinical and clinical studies. We also discuss the durability and breadth of immune response induced by VVVs and boosters. Finally, we present challenges associated with VVVs and offer solutions for overcoming certain limitations of current vaccine regimens. Collectively, this review provides the rationale for expanding the portfolio of VVVs against SARS-CoV-2.


Subject(s)
COVID-19/prevention & control , Genetic Vectors/immunology , Immunogenicity, Vaccine , SARS-CoV-2/immunology , Viral Vaccines/genetics , Viral Vaccines/immunology , Animals , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/immunology , Antibodies, Viral/blood , Antibodies, Viral/immunology , COVID-19/immunology , COVID-19 Vaccines/genetics , COVID-19 Vaccines/immunology , Clinical Trials as Topic , Disease Models, Animal , Immunity, Cellular , Immunity, Humoral , Immunity, Innate , Immunization, Secondary , Spike Glycoprotein, Coronavirus/genetics , Vaccination , Viral Vaccines/classification
14.
Front Immunol ; 12: 824728, 2021.
Article in English | MEDLINE | ID: covidwho-1686477

ABSTRACT

We generated an optimized COVID-19 vaccine candidate based on the modified vaccinia virus Ankara (MVA) vector expressing a full-length prefusion-stabilized SARS-CoV-2 spike (S) protein, termed MVA-CoV2-S(3P). The S(3P) protein was expressed at higher levels (2-fold) than the non-stabilized S in cells infected with the corresponding recombinant MVA viruses. One single dose of MVA-CoV2-S(3P) induced higher IgG and neutralizing antibody titers against parental SARS-CoV-2 and variants of concern than MVA-CoV2-S in wild-type C57BL/6 and in transgenic K18-hACE2 mice. In immunized C57BL/6 mice, two doses of MVA-CoV2-S or MVA-CoV2-S(3P) induced similar levels of SARS-CoV-2-specific B- and T-cell immune responses. Remarkably, a single administration of MVA-CoV2-S(3P) protected all K18-hACE2 mice from morbidity and mortality caused by SARS-CoV-2 infection, reducing SARS-CoV-2 viral loads, histopathological lesions, and levels of pro-inflammatory cytokines in the lungs. These results demonstrated that expression of a novel full-length prefusion-stabilized SARS-CoV-2 S protein by the MVA poxvirus vector enhanced immunogenicity and efficacy against SARS-CoV-2 in animal models, further supporting MVA-CoV2-S(3P) as an optimized vaccine candidate for clinical trials.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/prevention & control , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Vaccines, DNA/immunology , Viral Vaccines/immunology , Aged , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19/mortality , COVID-19 Vaccines/genetics , Cell Line, Tumor , Chick Embryo , Chlorocebus aethiops , Cytokines/analysis , Female , HeLa Cells , Humans , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , Plasmids/genetics , Spike Glycoprotein, Coronavirus/genetics , Vaccines, DNA/genetics , Vaccinia virus/immunology , Vero Cells , Viral Vaccines/genetics
15.
PLoS One ; 17(2): e0263684, 2022.
Article in English | MEDLINE | ID: covidwho-1674018

ABSTRACT

Since the SARS-CoV-2 infection was identified in December 2019, SARS-CoV-2 infection has rapidly spread worldwide and has become a significant pandemic disease. In addition, human death and serious health problem caused by SARS-CoV-2 infection, the socio-economic impact has been very serious. Here, we describe the development of the viral vector vaccine, which is the receptor-binding domain (RBD) of SARS-CoV-2 expressed on the surface of Newcastle disease virus (LVP-K1-RBD19). The RBD protein concentrations on the viral surface were measured by the sandwich ELISA method. 106.7 TCID50/ml of LVP-K1-RBD19 has a 0.17 µg of RBD protein. Optical density (OD) values of mouse sera inoculated with 10 µg of RBD protein expressed on the surface of LVP-K1-RBD19 generated 1.78-fold higher RBD-specific antibody titers than mice inoculated with 10 µg RBD protein with alum at 28 dpi. Moreover, mice inoculated with 10 µg of RBD protein expressed on the surface of LVP-K1-RBD19 virus showed more than 80% neutralization at 1:256 against the SARS-CoV-2 pseudovirus. These results demonstrated that inactivated LVP-K1-RBD19 virus produces neutralizing antibodies against SARS-CoV-2 in a short period and could be elect protective immunity in humans and LVP-K1-RBD19 will be a good candidate for the COVID-19 vaccine.


Subject(s)
Angiotensin-Converting Enzyme 2/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19 Vaccines/immunology , COVID-19/prevention & control , Newcastle disease virus/immunology , Viral Vaccines/immunology , Animals , COVID-19/immunology , COVID-19/virology , Female , Humans , Mice , Mice, Inbred BALB C , Newcastle disease virus/genetics , Protein Binding , Protein Domains , SARS-CoV-2/immunology
17.
Med Sci Monit ; 28: e936199, 2022 Feb 01.
Article in English | MEDLINE | ID: covidwho-1662873

ABSTRACT

The omicron variant of SARS-CoV-2, B.1.1.529, was included in the World Health Organization (WHO) list of variants of concerns (VOC) on 26 November 2021. Within only three months, omicron has spread rapidly to become the dominant variant in many countries. Studies have begun to evaluate the virulence, transmissibility, and degree of immune protection from current SARS-CoV-2 vaccines or previous of infection with the omicron variant. On 21 January 2022, the WHO published its seventh technical update and recommendations for priority actions in response to the omicron SARS-CoV-2 variant and cautioned that the overall risk from omicron remains high. At the start of this third year of the global COVID-19 pandemic, this editorial aims to summarize the evidence that supports the current priority recommendations and response from the WHO regarding the omicron variant of SARS-CoV-2, B.1.1.529.


Subject(s)
Health Policy/trends , Pandemics/prevention & control , SARS-CoV-2/pathogenicity , COVID-19/genetics , COVID-19/prevention & control , COVID-19 Vaccines/immunology , Humans , Viral Vaccines/immunology , World Health Organization
18.
Front Immunol ; 12: 812176, 2021.
Article in English | MEDLINE | ID: covidwho-1662586

ABSTRACT

Although not being the first viral pandemic to affect humankind, we are now for the first time faced with a pandemic caused by a coronavirus. The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has been responsible for the COVID-19 pandemic, which caused more than 4.5 million deaths worldwide. Despite unprecedented efforts, with vaccines being developed in a record time, SARS-CoV-2 continues to spread worldwide with new variants arising in different countries. Such persistent spread is in part enabled by public resistance to vaccination in some countries, and limited access to vaccines in other countries. The limited vaccination coverage, the continued risk for resistant variants, and the existence of natural reservoirs for coronaviruses, highlight the importance of developing additional therapeutic strategies against SARS-CoV-2 and other coronaviruses. At the beginning of the pandemic it was suggested that countries with Bacillus Calmette-Guérin (BCG) vaccination programs could be associated with a reduced number and/or severity of COVID-19 cases. Preliminary studies have provided evidence for this relationship and further investigation is being conducted in ongoing clinical trials. The protection against SARS-CoV-2 induced by BCG vaccination may be mediated by cross-reactive T cell lymphocytes, which recognize peptides displayed by class I Human Leukocyte Antigens (HLA-I) on the surface of infected cells. In order to identify potential targets of T cell cross-reactivity, we implemented an in silico strategy combining sequence-based and structure-based methods to screen over 13,5 million possible cross-reactive peptide pairs from BCG and SARS-CoV-2. Our study produced (i) a list of immunogenic BCG-derived peptides that may prime T cell cross-reactivity against SARS-CoV-2, (ii) a large dataset of modeled peptide-HLA structures for the screened targets, and (iii) new computational methods for structure-based screenings that can be used by others in future studies. Our study expands the list of BCG peptides potentially involved in T cell cross-reactivity with SARS-CoV-2-derived peptides, and identifies multiple high-density "neighborhoods" of cross-reactive peptides which could be driving heterologous immunity induced by BCG vaccination, therefore providing insights for future vaccine development efforts.


Subject(s)
BCG Vaccine/immunology , COVID-19/immunology , Cross Reactions/immunology , Peptides/immunology , SARS-CoV-2/immunology , T-Lymphocytes/immunology , Viral Vaccines/immunology , Humans , Pandemics/prevention & control , Vaccination/methods
19.
EBioMedicine ; 76: 103841, 2022 Feb.
Article in English | MEDLINE | ID: covidwho-1649699

ABSTRACT

Currently licensed COVID-19 vaccines are all designed for intramuscular (IM) immunization. However, vaccination today failed to prevent the virus infection through the upper respiratory tract, which is partially due to the absence of mucosal immunity activation. Despite the emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, the next generation of COVID-19 vaccine is in demand and intranasal (IN) vaccination method has been demonstrated to be potent in inducing both mucosal and systemic immune responses. Presently, although not licensed, various IN vaccines against SARS-CoV-2 are under intensive investigation, with 12 candidates reaching clinical trials at different phases. In this review, we give a detailed description about current status of IN COVID-19 vaccines, including virus-vectored vaccines, recombinant subunit vaccines and live attenuated vaccines. The ongoing clinical trials for IN vaccines are highlighted. Additionally, the underlying mechanisms of mucosal immunity and potential mucosal adjuvants and nasal delivery devices are also summarized.


Subject(s)
COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , SARS-CoV-2/immunology , Administration, Intranasal , COVID-19/immunology , COVID-19/virology , COVID-19 Vaccines/immunology , Clinical Trials as Topic , Humans , Immunity, Mucosal , SARS-CoV-2/isolation & purification , Viral Vaccines/administration & dosage , Viral Vaccines/immunology
20.
J Immunol ; 208(3): 562-570, 2022 02 01.
Article in English | MEDLINE | ID: covidwho-1625582

ABSTRACT

Aging is associated with functional deficits in the naive T cell compartment, which compromise the generation of de novo immune responses against previously unencountered Ags. The mechanisms that underlie this phenomenon have nonetheless remained unclear. We found that naive CD8+ T cells in elderly humans were prone to apoptosis and proliferated suboptimally in response to stimulation via the TCR. These abnormalities were associated with dysregulated lipid metabolism under homeostatic conditions and enhanced levels of basal activation. Importantly, reversal of the bioenergetic anomalies with lipid-altering drugs, such as rosiglitazone, almost completely restored the Ag responsiveness of naive CD8+ T cells. Interventions that favor lipid catabolism may therefore find utility as adjunctive therapies in the elderly to promote vaccine-induced immunity against targetable cancers and emerging pathogens, such as seasonal influenza viruses and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).


Subject(s)
Aging/immunology , CD8-Positive T-Lymphocytes/immunology , Immunocompetence/drug effects , Lipid Metabolism , Adult , Aged , Aged, 80 and over , Apoptosis , CD8-Positive T-Lymphocytes/metabolism , COVID-19/immunology , Cancer Vaccines/immunology , Cell Division , Female , Fenofibrate/pharmacology , Glucose/metabolism , HLA-A2 Antigen/immunology , Humans , Hypolipidemic Agents/pharmacology , Hypolipidemic Agents/therapeutic use , Influenza, Human/immunology , Lipid Metabolism/drug effects , Lymphocyte Activation , MART-1 Antigen/chemistry , MART-1 Antigen/immunology , Male , Middle Aged , Neoplasms/immunology , Peptide Fragments/immunology , Rosiglitazone/pharmacology , Single-Blind Method , Vaccination , Viral Vaccines/immunology , Young Adult
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