The number of confirmed COVID-19 cases worldwide amounted to 50 million at the beginning of November 2020. This is clearly not enough for the formation of herd immunity, which will prevent repeated outbreaks of the disease. Quarantine measures can only curb the spread of the disease to some extent, therefore specific preventive measures are needed to create collective immunity to COVID-19.The underlying principle of collective immunity is indirect protection of the whole of the population by immunising a certain part of it. Vaccination is the most effective approach to prevention of epidemic outbreaks. The aim of the study was to analyse promising approaches to the development of vaccines against novel coronavirus COVID-19 infection. The paper summarises data on development studies and clinical trials of COVID-19 vaccines conducted in different countries. It analyses the pros and cons of different platforms for vaccine development (attenuated vaccines, inactivated vaccines, subunit vaccines, DNA and RNA vaccines, recombinant vector vaccines). The paper presents a potential design of novel vaccines. It was concluded that COVID-19 vaccines might be developed both for immunising high-risk groups and for mass immunisation. An optimal solution for the second task would be to develop human or monkey adenovirus vector-based vaccines whose mass production has already been unveiled.

The progress of the COVID-19 pandemic initiated research to develop vaccines against this novel coronavirus infection. The WHO and national regulatory authorities in many countries have elaborated guidelines to speed up the development and authorisation of COVID-19 vaccines. The aim of the study was to analyse international and Russian regulatory recommendations for the development and fast-track approval of COVID-19 vaccines in the context of the pandemic, as well as to summarise the preliminary published results of the first stages of preclinical and clinical studies. The paper analyses approaches to fast-track approval of medicines in the face of the pandemic in Russia, the European Union, and the United States. It summarises regulatory requirements for the quality of COVID-19 vaccines, as well as for preclinical, and clinical studies. It describes the first results of COVID-19 vaccine development. The analysed regulatory documents allow for accelerated authorisation due to reduction of time spent on evaluation of vaccine quality, safety, and efficacy. Another option is the so-called conditional marketing authorisation when a vaccine is registered based on incomplete preclinical and clinical data provided that all the studies will be completed after the vaccine authorisation. The paper summarises the results of clinical trials of COVID-19 vaccines. The few published preliminary results of the first phases of COVID-19 vaccine clinical trials demonstrate the vaccines’ good tolerability, safety, and immunogenicity. Evaluation of adenovirusbased vaccines showed that almost half of the volunteers had had high antibody titers to adenovirus before the study, which resulted in milder adverse reactions and low immunogenicity. In addition, the immune response was weaker in the older group of subjects (45–60 years) as compared to the subjects younger than 45 years. The results of the analysis of regulatory requirements for the development and marketing authorisation of COVID-19 vaccines in the context of the pandemic, as well as of national and international regulatory approaches to vaccine development and authorisation can be used as a basis for the development of Russian requirements for COVID-19 vaccines in the context of the pandemic.

One of priority issues of the present-day healthcare system is development of new vaccines and improvement of existing ones due to decreasing immunocompetence of the population, emergence of new infections and reemergence of old ones which were previously thought to be under control. Adjuvants have proven to be integral and important components of modern vaccines, as they enhance immune response to the vaccine antigen. However, despite a lot of effort put into their development, only a small number of adjuvants are currently used in clinical practice. The aim of the study was to systematise literature data on the adjuvants’ mechanisms of action, their specific structure, composition, and stimulation effects that mediate their immunoadjuvant properties. The paper summarises data on adjuvants used as components in licensed vaccines, describes their characteristics, analyses molecular mechanisms of their action in order to establish correlation between their structure and activity, which is important for the development of more efficacious and safe adjuvants. The paper cites advanced developments aimed at enhancing stimulation effects of existing adjuvants. It concludes by stating that the key research area aimed at improving vaccination efficacy is the study of mechanisms that contribute to the development of effective protection against infectious agents, as well as analysis of how to use adjuvants to stimulate the body’s defensive mechanisms, primarily by impacting the innate immunity.

Some types of immunotherapy of malignant tumours are aimed at restoration of T-cells’ ability to recognize and eliminate cancer. Programmed cell death ligand-1 (PD-L1) overexpression is characteristic of many human tumours and is associated with poor prognosis for patients. The development of monoclonal antibodies (mAbs) specific for PD-L1 or PD-1 is a promising area of immunotherapy of malignant tumours. However, before a therapeutic antibody-based product enters the market, it is necessary to ensure its safety and efficacy, i.e. perform a full scope of preclinical and clinical studies. The aim of the study was to develop and validate a bioanalytical method that does not require additional labeling and that could be used for determination of mAbs specific for human PD-L1 in the blood serum of a biological test system during preclinical studies. Materials and methods: an antigen in the form of a dimer of PD-1 extra-cellular domain covalently bonded to the Fc-fragment of human IgG (R&D Systems, USA) was used in the study. The antigen was immobilised on Dip and Read™ Protein A biosensors (Fortebio, USA). The therapeutic anti-PD-1 antibody GNR-051 was developed and produced by IBC “Generium” (Russia). The healthy cynomolgus monkey serum samples used as matrix were obtained from the Research Institute of Medical Primatology (Sochi, Russia). The assessment of binding was performed using Octet® QKe interferometer (Fortebio, USA) by real-time analysis of the dose-dependent rate of the antigen-antibody complex formation. Results: the paper presents experimental data on the development and validation of the test method for determination of the therapeutic PD-1-binding mAb concentration in cynomolgus monkey serum in the antibody concentration range from 2 to 2500 µg/mL. The authors assessed the calibration curve reliability, between-run and within-run precision and accuracy, dilution linearity, specificity and selectivity of the test method. Conclusions: the authors developed and validated the biolayer interferometry-based method for determination of therapeutic mAbs concentration. The method was shown to comply with the Eurasian Economic Union’s regulatory requirements in terms of the main validation parameters: analytical range, accuracy, precision, and selectivity. 

The hemostimulating properties of granulocyte-macrophage colony-stimulating factor (GM-CSF) make possible its clinical use in alleviating side effects of anti-cancer radio- and chemotherapy, in bone marrow transplantation, and in the treatment of some primary immunodeficiency conditions associated with leukopenia. The State Research Center of Virology and Biotechnology “Vector” of the Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing has developed a high-performance technology for production of recombinant human GM-CSF (rhGM-CSF) based on a recombinant E. coli strain. The aim of the study was to assess hemostimulating activity of the rhGM-CSF preparation obtained using the new developed technology, as observed in cell culture and in the mice model of myelosuppression induced by cyclophosphamide administration. Materials and methods: in vitro evaluation of rhGM-CSF hemostimulating activity was performed by MTT assay in the commercial HL-60 promyelocytic leukemia cell culture with preliminary suppression of cell growth rate by adding a low concentration of dimethyl sulfoxide to the medium. In vivo studies were carried out in CBA/CaLac mice with cyclophosphamide-induced myelosuppression. The hemostimulating properties of the drug were evaluated after subcutaneous administration of 1–175 µg/kg doses for 4–5 days, following administration of a cytostatic agent. The total number of leukocytes and the content of their morphological forms were determined in blood samples taken at different time points after the drug administration. The statistical processing of the experimental data was based on analysis of variance using Statgraphics v. 5.0 software. Results: the proliferative activity of HL-60 cells incubated with the rhGM-CSF preparation for 72 hours was shown to be dose-dependent. The highest values of the increase in proliferative activity associated with an increase in the drug dose were observed in the concentration range from 0.04 to 0.64 ng/mL (proliferative activity increased by 11–18% when the dose was increased twofold). The experiments in mice demonstrated a two-phase pattern of the dose-dependent effect. The drug showed the highest hemostimulating effect at the dose of 90 µg/kg. Conclusions: the rhGM-CSF preparation obtained using the new developed technology has a pronounced hemostimulating activity confirmed by both in vitro and in vivo test systems. 

Preventive immunisation against anthrax is carried out in accordance with the national Immunisation Schedule for Epidemic Settings. The vaccination is performed using a live vaccine—a freeze-dried suspension of Bacillus anthracis STI-1 vaccine strain spores in a stabilizing media. Improvement of the quality control of immunobiological medicines is a pressing issue and an integral part of the quality management system. The aim of study was to streamline quality control of live anthrax vaccine in terms of the following test parameters: identification and specific activity (total spore concentration). Materials and methods: identification and specific activity (total spore concentration) tests were performed for samples of live anthrax vaccine, batch 266, produced by the 48 Central Scientific Research Institute. The identification test was performed using the B. anthracis immunochromatography test kit for express detection and identification of anthrax pathogen spores produced by the State Research Center for Applied Microbiology and Biotechnology (Obolensk). The specific activity (total spore concentration) was assessed by the visual method and calculated in the Goryaev chamber using the industry reference standard of bacterial suspension turbidity equivalent to 10 IU—OSO 42-28-85 (by the Scientific Centre for Expert Evaluation of Medicinal Products). The number of live spores in live anthrax vaccine was determined by the microbiological method (by inoculating media). The statistical processing of the results was performed using Excel and Statistica 10.0. Results: the authors provided theoretical and experimental substantiation to support the feasibility of using immunochromatography as an alternative identification test method for live anthrax vaccine. Test samples dilutions of 108 microbial cells per millilitre and 109 microbial cells per millilitre are used in the test. The authors developed a test procedure for determination of the total spore concentration (specific activity) in live anthrax vaccine using an industry reference standard of turbidity equivalent to 10 IU, and proposed a formula for calculation of the total spore concentration. Conclusions: the developed test procedures could be recommended for inclusion in the live anthrax vaccine specification files as alternative methods of quality control.