The COVID-19 pandemic is ongoing, and the need for safe and effective vaccines to prevent infection and to control spread of the virus remains urgent. Here, we report the development of a SARS-CoV-2 subunit vaccine candidate (Betuvax-CoV-2) based on RBD and SD1 domains of the spike (S) protein fused to a human IgG1 Fc fragment. The antigen is adsorbed on betulin adjuvant, forming spherical particles with a size of 100–180 nm, mimicking the size of viral particles. Here we confirm the potent immunostimulatory activity of betulin adjuvant, and demonstrate that two immunizations of mice with Betuvax-CoV-2 elicited high titers of RBD-specific antibodies. The candidate vaccine was also effective in stimulating a neutralizing antibody response and T cell immunity. The results indicate that Betuvax-CoV-2 has good potential for further development as an effective vaccine against SARS-CoV-2.

Public health threat coming from a rapidly developing COVID-19 pandemic calls for developing safe and effective vaccines with innovative designs. This paper presents preclinical trial results of “Betuvax-CoV-2”, a vaccine developed as a subunit vaccine containing a recombinant RBD-Fc fusion protein and betulin-based spherical virus-like nanoparticles as an adjuvant (“Betuspheres”). The study aimed to demonstrate vaccine safety in mice, rats, and Chinchilla rabbits through acute, subchronic, and reproductive toxicity studies. Along with safety, the vaccine demonstrated protective efficacy through SARS-CoV-2-neutralizing antibody production in mice, rats, hamsters, rabbits, and primates (rhesus macaque), and lung damage and infection protection in hamsters and rhesus macaque model. Eventually, “Betuvax-CoV-2” was proved to confer superior efficacy and protection against the SARS-CoV-2 in preclinical studies. Based on the above results, the vaccine was enabled to enter clinical trials that are currently underway.

Public health threat coming from a rapidly developing COVID-19 pandemic calls for developing safe and effective vaccines with innovative designs. This paper presents preclinical trial results of “Betuvax-CoV-2”, a vaccine developed as a subunit vaccine containing a recombinant RBD-Fc fusion protein and betulin-based spherical virus-like nanoparticles as an adjuvant (“Betuspheres”). The aim of the study was to demonstrate vaccine safety in mice, rats, and Chinchilla rabbits through acute, subchronic, and reproductive toxicity studies. Along with safety, the vaccine demonstrated protective efficacy through SARS-CoV-2-neutralizing antibody production in mice, rats, hamsters, rabbits, and primates (rhesus macaque), and lung damage and infection protection in hamsters and rhesus macaque model. Eventually, “Betuvax-CoV-2” was proved to confer superior efficacy and protection against the SARS-CoV-2 in preclinical studies. Based on the above results, the vaccine was enabled to enter clinical trials that are currently underway.

Introduction. Using of immunoglobulins containing SARS-CoV-2 neutralizing antibodies may be an effective and safe tool for COVID-19 treatment. An intravenous immunoglobulin COVID-globulin from donor blood plasma containing SARS-CoV-2 neutralizing antibodies was developed at Joint-Stock Company Nacimbio.Aim. A pilot study of the safety of the "COVID-globulin".Materials and methods. When studying the safety of the preparation in animals the following parameters were evaluated: general toxicity, thrombogenic potential, influence on hematological and biochemical parameters, blood clotting and hemolytic activity, determination of local irritant action, pyrogenic properties, bacterial endotoxins, allergic effect of the drug preparation and its physicochemical characteristics.Results and discussion. Safety studies of "COVID-globulin" in animals showed no signs of intoxication, local irritant action and thrombogenic properties. Macroscopic and histological examination of the organs of rats treated with COVID-globulin showed no signs of necrosis, inflammation, atypia, or any significant pathological changes. Hematological and biochemical parameters of the blood of laboratory animals after the administration of "COVID-globulin" corresponded to the reference values. Administration of COVID-globulin to rabbits did not activate blood clot formation. The IgG subclasses distribution in the preparation corresponded to that in human plasma. The activity of the Fc-function of the immunoglobulin molecule was more than 130 % compared to the reference standard preparation, the concentration of the prekallikrein activator in the COVID-globulin ranged from 4.2 to 4.8 IU/ml, anticomplementary activity was less than 1 unit complement per 1 mg of protein.Conclusion. The results of all studies have demonstrated a high level of safety of the developed COVID-globulin preparation, which meets the safety requirements for human immunoglobulins for intravenous administration by national regulatory documents and the European Pharmacopoeia.

Background: The authors describe the developmental process of intravenous anti-COVID-19 hyperimmune immunoglobulin from anti-SARS-CoV-2 neutralizing antibody-containing plasma. Furthermore, the aut... Plain language summary An intravenous immunoglobulin with a high concentration of SARS-CoV-2-neutralizing antibodies was prepared from COVID-19 convalescent plasma, which could be utilized as a pas... Tweetable abstract Pure and safe intravenous immunoglobulin with a high concentration of SARS-CoV-2 neutralizing antibodies was produced from #COVID19 convalescent plasma and demonstrated protectiv...

The development of an effective combined vaccine represents a crucial strategy for preventing outbreaks of infectious diseases and reducing the burden on healthcare resources. Developing a combined vaccine against both influenza and the coronavirus is a promising approach, but it is still in the early stages of development. This paper reports on a novel combined pentavalent candidate vaccine that has shown promising results in mice, with statistically significant differences in mean antibody titer against the coronavirus and the influenza antigens compared to placebo. We have shown that the coronavirus antigen is capable of inducing an immune response autonomously, regardless of the presence of the influenza antigens in a combined vaccine. On the other hand, the presence of the coronavirus antigen in a combined vaccine showed to enhance the immune response against some of the studied influenza antigens, suggesting that these antigens may act in synergy and elicit an enhanced immune response. The absence of dose-dependent difference in mean antibody titer within the same antigenic groups of vaccine preparations suggested that even small amounts of the coronavirus and the influenza antigens could induce an immune response just as good as high-dose vaccine preparations, which certainly has important safety and cost implications. The vaccine is soon to be ready for clinical trials and mass production.