The past, present, prospects and problems of improving the specifi c prevention of brucellosis

Brucellosis remains the most widespread zoonotic infection in the world. Th e spread of the infection is controlled by animals vaccination because the high morbidity rate of the population is associated with the spread of infection among livestock. Th e research is ongoing on a commercial preparation of an eff ective and safe vaccine for immunization of humans and animals against brucellosis. Th e review is devoted to the prospects and problems of improving the specifi c prevention of brucellosis. Th e authors analyzed scientifi c publications from various databases of electronic libraries, such as PubMed, e-library, CyberLeninka, etc.

Novel virus-like nanoparticle vaccine effectively protects animal model from SARS-CoV-2 infection

The key to battling the COVID-19 pandemic and its potential aftermath is to develop a variety of vaccines that are efficacious and safe, elicit lasting immunity, and cover a range of SARS-CoV-2 variants. Recombinant viral receptor-binding domains (RBDs) are safe vaccine candidates but often have limited efficacy due to the lack of virus-like immunogen display pattern. Here we have developed a novel virus-like nanoparticle (VLP) vaccine that displays 120 copies of SARS-CoV-2 RBD on its surface. This VLP-RBD vaccine mimics virus-based vaccines in immunogen display, which boosts its efficacy, while maintaining the safety of protein-based subunit vaccines. Compared to the RBD vaccine, the VLP-RBD vaccine induced five times more neutralizing antibodies in mice that efficiently blocked SARS-CoV-2 from attaching to its host receptor and potently neutralized the cell entry of variant SARS-CoV-2 strains, SARS-CoV-1, and SARS-CoV-1-related bat coronavirus. These neutralizing immune responses induced by the VLP-RBD vaccine did not wane during the two-month study period. Furthermore, the VLP-RBD vaccine effectively protected mice from SARS-CoV-2 challenge, dramatically reducing the development of clinical signs and pathological changes in immunized mice. The VLP-RBD vaccine provides one potentially effective solution to controlling the spread of SARS-CoV-2.

Immunological considerations and vaccines against COVID-19

The outbreak COVID-19 is considered as a revolution in history of biological science. SARS-CoV-2 is a main cause of COVID-19 having resemblance with MERS-CoV and SARS-CoV. The response of host to the infection of SARS-CoV is multiform and strong. Initially, an effective host defense in the lung is affiliated with disease resolution and mild symptoms. The escaping of virus from immune response can lead to damage the alveoli, systematic inflammation, and ineffective lung repair mechanism with associated organ dysfunction. The immunological responses are necessary to fight with the virus and an effective and a safe vaccine is needed to overcome the pandemic. The development of vaccine is progressing fast, billions of dollars committed with more than 200 candidates before even knowing whether a vaccine candidate will succeed.

COVID-19 vaccine: Potential candidates, achievements, and challenges

Severe acute respiratory syndrome [SARS]-CoV-2, which is the causative agent of Coronavirus Disease 2019 [COVID-19] disease, has engulfed more than 2.4 million people and still counting. As this pandemic is at its peak and is responsible for more than 100 million infected people worldwide, there is an urgent need to develop an effective vaccine to stop the COVID-19 disease. More than 220 vaccine candidates are in the pre-development stage while 15 candidates are in the developmental stage, from which Pfizer/BioNTech, Moderna, and some other vaccines have received approval by some countries for emergency use only. Fever, tiredness, headache, joint pain, swelling at the injection site and some other common effects have been found by using these vaccines. Efficacy, rapid mass production, and long-term immunity as well as acceptance of vaccination by society are the main challenges in developing a safe vaccine against COVID-19 despite the fact that some vaccines have over 90% efficiency against COVID-19 and are useful in developing immunity as well.

The trade-off between mobility and vaccination for COVID-19 control: a metapopulation modelling approach

November 2020 received a string of encouraging results from leading vaccine developers raising hopes for the imminent availability of an effective and safe vaccine against the SARS-CoV-2. In the present work, we discuss the theoretical impact of introducing a vaccine across a range of scenarios. In particular, we investigate how vaccination coverage, efficacy and delivery time affect the control of the transmission dynamics in comparison to mobility restrictions. The analysis is based on a metapopulation epidemic model structured by risk. We perform a global sensitivity analysis using the Sobol method. Our analysis suggest that the reduction of mobility among patches plays a significant role in the mitigation of the disease close to the effect of immunization coverage of 30% achieved in four months. Moreover, for an immunization coverage between 20% and 50% achieved in the first half of 2021 with a vaccine efficacy between 70% and 95%, the percentage reduction in the total number of SARS-CoV-2 infections is between 30% and 50% by the end of 2021 in comparison with the no vaccination scenario.

Frequency of Accelerated Bacillus Calmette-Guerin Response in Bacillus Calmette-Guerin Vaccinated Children

Background: BCG is a vaccine obtained by attenuating Mycobacterium bovis. It is a fairly safe vaccine with no associated complications. Aim: To determine the frequency of accelerated BCG response in BCG vaccinated children. Study design: Descriptive case series. Methodology: A total of 124 already BCG vaccinated patients, having age in the range of 6 months to 10 years of either gender were included in the study. Patients with known case of TB and any other systemic disease were excluded. After this, BCG vaccination was given by the researcher himself who noted the in-duration after 72 hrs of BCG vaccination accelerated response of BCG. Chi square test was applied with P-value <0.05 as significant. Results: Mean age was 6.02±2.22 years. Out of the 124 patients, 63(50.81%) were male and 61(49.19%) were females. Mean duration of previous BCG was 4.75±2.41 years. Frequency of accelerated BCG response in BCG vaccinated children was found in 76(61.29%) patients. Conclusion: This study concluded that the frequency of accelerated BCG response in BCG vaccinated children was 61.29%. So, we suggested that public awareness programs should be arranged to educate people for compulsory BCG vaccination of their children. Keywords: Bacillus Calmette-Guerin (BCG) Vaccine, Accelerated BCG Response and Tuberculosis.

ChAdOx1 nCoV-19 (AZD1222) vaccine candidate significantly reduces SARS-CoV-2 shedding in ferrets

Vaccines against SARS-CoV-2 are likely to be critical in the management of the ongoing pandemic. A number of candidates are in Phase III human clinical trials, including ChAdOx1 nCoV-19 (AZD1222), a replication-deficient chimpanzee adenovirus-vectored vaccine candidate. In preclinical trials, the efficacy of ChAdOx1 nCoV-19 against SARS-CoV-2 challenge was evaluated in a ferret model of infection. Groups of ferrets received either prime-only or prime-boost administration of ChAdOx1 nCoV-19 via the intramuscular or intranasal route. All ChAdOx1 nCoV-19 administration combinations resulted in significant reductions in viral loads in nasal-wash and oral swab samples. No vaccine-associated adverse events were observed associated with the ChAdOx1 nCoV-19 candidate, with the data from this study suggesting it could be an effective and safe vaccine against COVID-19. Our study also indicates the potential for intranasal administration as a way to further improve the efficacy of this leading vaccine candidate.

mRNA-based SARS-CoV-2 vaccine candidate CVnCoV induces high levels of virus-neutralising antibodies and mediates protection in rodents

AbstractmRNA technologies have recently proven clinical efficacy against coronavirus disease 2019 and are among the most promising technologies to address the current pandemic. Here, we show preclinical data for our clinical candidate CVnCoV, a lipid nanoparticle-encapsulated mRNA vaccine that encodes full-length, pre-fusion stabilised severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike protein. In contrast to previously published approaches, CVnCoV is exclusively composed of naturally occurring nucleotides. Immunisation with CVnCoV induced strong humoral responses with high titres of virus-neutralising antibodies and robust T-cell responses. CVnCoV vaccination protected hamsters from challenge with wild-type SARS-CoV-2, demonstrated by the absence of viral replication in the lungs. Hamsters vaccinated with a suboptimal dose of CVnCoV leading to breakthrough viral replication exhibited no evidence of vaccine-enhanced disease. Overall, data presented here provide evidence that CVnCoV represents a potent and safe vaccine candidate against SARS-CoV-2.

Principles and Challenges in anti-COVID-19 Vaccine Development

The number of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected patients keeps rising in most of the European countries despite the pandemic precaution measures. The current antiviral and anti-inflammatory therapeutic approaches are only supportive, have limited efficacy, and the prevention in reducing the transmission of SARS-CoV-2 virus is the best hope for public health. It is presumed that an effective vaccination against SARS-CoV-2 infection could mobilize the innate and adaptive immune responses and provide a protection against severe forms of coronavirus disease 2019 (COVID-19) disease. As the race for the effective and safe vaccine has begun, different strategies were introduced. To date, viral vector-based vaccines, genetic vaccines, attenuated vaccines, and protein-based vaccines are the major vaccine types tested in the clinical trials. Over 80 clinical trials have been initiated; however, only 18 vaccines have reached the clinical phase II/III or III, and 4 vaccine candidates are under consideration or have been approved for the use so far. In addition, the protective effect of the off-target vaccines, such as <i>Bacillus</i> Calmette-Guérin and measles vaccine, is being explored in randomized prospective clinical trials with SARS-CoV-2-infected patients. In this review, we discuss the most promising anti-COVID-19 vaccine clinical trials and different vaccination strategies in order to provide more clarity into the ongoing clinical trials.

Immunogenicity and Protective Efficacy of an Intranasal Live-attenuated Vaccine Against SARS-CoV-2 in Preclinical Animal Models

ABSTRACTThe global deployment of an effective and safe vaccine is currently a public health priority to curtail the coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we evaluated a Newcastle disease virus (NDV)-based intranasal vectored-vaccine in mice and hamsters for its immunogenicity, safety and protective efficacy in challenge studies with SARS-CoV-2. The recombinant (r)NDV-S vaccine expressing spike (S) protein of SARS-CoV-2 administrated via intranasal route in mice induced high levels of SARS-CoV-2-specific neutralizing immunoglobulin A (IgA) and IgG2a antibodies and T cell-mediated immunity. Hamsters vaccinated with two doses of vaccine showed complete protection from clinical disease including lung infection, inflammation, and pathological lesions after SARS-CoV-2 challenge. Importantly, a single or double dose of intranasal rNDV-S vaccine completely blocked SARS-CoV-2 shedding in nasal turbinate and lungs within 4 days of vaccine administration in hamsters. Taken together, intranasal administration of rNDV-S has the potential to control infection at the site of inoculation, which should prevent both the clinical disease and transmission to halt the spread of the COVID-19 pandemic.