The research conducted in this preclinical study assesses QazCovid-live, a live attenuated COVID-19 vaccine created in Kazakhstan, by conducting preclinical evaluations of safety, immunogenicity, and allergenicity in various animal models, including mice, rats, hamsters, and guinea pigs. The vaccine, developed by attenuating SARS-CoV-2 via numerous Vero cell passages, had no significant adverse effects in acute and subacute toxicity assessments, even at elevated dosages. Allergenicity testing indicated the absence of both immediate and delayed hypersensitivity reactions. Immunogenicity evaluations revealed strong virus-neutralizing antibody responses, especially following intranasal and intratracheal delivery. Studies on reversibility and transmission further validated the vaccine’s stability and non-pathogenicity. The data indicate that QazCovid-live is safe, immunogenic, and prepared for clinical trials, presenting a potential strategy for COVID-19 prevention.

Peste des petits ruminants (PPR) is an extremely contagious viral disease that significantly affects the health of small ruminants and the economies of livestock, particularly in areas adjacent to endemic regions. This study focused on assessing the vulnerability of different domestic and wild animal species in Kazakhstan, which includes local sheep and goats, African Cameroon goats, saigas, calves, and ground squirrels, to infection by the PPR virus (PPRV). Experimental infections used a virulent strain of PPRV (Nigeria 76/1), with animals being monitored over a period of 21–28 days to evaluate clinical signs, pathological lesions, and viral dissemination. The manifestation of disease differed across species, breed, and age. In Cameroon, goats and saigas displayed severe illness with a mortality rate of 100% and elevated virus levels in key organs, whereas local sheep and goats presented age-related subacute, abortive, and latent manifestations. Calves exhibited mild, subclinical infections, while ground squirrels showed no susceptibility. Viral shedding was observed in the secretions of infected animals, with transmission occurring through airborne and alimentary pathways. No virus carriage was detected in the animals that had recovered. The investigation emphasizes the notable variations in PPRV pathogenesis and transmission risk among different species, highlighting the necessity for focused surveillance and control strategies to avert incursions in PPR-free areas like Kazakhstan.

Background/Objectives: Equine rhinopneumonia, caused by equine herpesvirus types 1 and 4 (EHV-1 and EHV-4), continues to be a significant health and economic concern in the global equine industry, particularly in Kazakhstan. While vaccines targeting EHV-1 are available, there is currently no licensed monovalent vaccine for EHV-4, and existing formulations offer limited protection against this serotype. This study aimed to develop and evaluate a freeze-dried, live-attenuated EHV-4 vaccine with improved safety, stability, and immunogenicity. Methods: A field isolate of EHV-4 was attenuated through serial passaging in primary lamb testicle (LT-KK49) cell cultures. Viral biomass was concentrated and formulated with various stabilizers before freeze-drying. The most effective stabilizer composition—sucrose, gelatin, and lactalbumin hydrolysate—was selected based on viral titer retention. Safety and immunogenicity were assessed in mice, guinea pigs, rabbits, donkeys, and horses. A guinea pig reproductive challenge model was used to evaluate protective efficacy. Results: The optimized lyophilized vaccine retained infectivity (>6.0 log₁₀ TCID_50/cm³) for at least six months at 4 °C. No adverse clinical signs were observed in any test species. Immunization induced robust neutralizing antibody responses in both small animals and equines. In the guinea pig model, vaccinated females demonstrated 100% pregnancy retention and fetal viability following challenge with a virulent EHV-4 strain. Conclusions: This freeze-dried, live-attenuated EHV-4 vaccine candidate is safe, immunogenic, and thermostable. It offers a promising platform for the targeted prevention of EHV-4 infection, particularly in young horses and in regions with limited cold-chain infrastructure.

The territory of the Republic of Kazakhstan is unfavorable for a number of infectious diseases of animals and humans that pose an enzootic biological threat. Such nosological units include anthrax, blackleg, rabies, leukemia, brucellosis, tuberculosis, pasteurellosis, sheep pox, camel pox, CCHF, highly pathogenic avian influenza, foot-and-mouth disease, tick-borne encephalitis, influenza A and B, infectious hepatitis, Newcastle disease, seasonal flu, coronavirus infection COVID-19, etc., some of which affect only animals or humans, and some affect both animals and humans. While some of these diseases are natural focal and pose a constant biological threat, others appear from time to time, penetrating from neighboring countries or develop as a result of movement from the wild - reservoirs and hidden carriers of pathogens. A number of exotic diseases pose a real threat of penetration from outside the country due to interstate movements of people, animals, feed and animal products.

Background and Aim. A year after the official declaration of the end of the pandemic, this study aimed to assess the epidemic situation by testing a small group of individuals for the presence of the SARS-CoV-2 virus and neutralizing antibodies. Materials and Methods. Nasopharyngeal swabs were collected to isolate SARS-CoV-2 virus in cell culture, while venous blood samples were tested for neutralizing antibodies using a quantitative neutralization reaction. The study included 20 participants (approximately 10% of the team), of whom 16 had been vaccinated against COVID-19, and 4 remained unvaccinated. Vaccinated individuals included 4 who received Sputnik V (over 30 months prior) and 12 who received QazCOVID-in. Results. All 20 participants demonstrated neutralizing antibodies against the Wuhan variant of the virus. For the Delta and Omicron variants, 19 participants showed neutralizing antibodies. Average antibody titers were 6.4 ± 1.39 log₂ for the Wuhan variant, 6.2 ± 1.89 log₂ for the Delta variant, and 4.75 ± 1.84 log₂ for the Omicron variant. Conclusion. The study highlights the persistence of antibodies against SARS-CoV-2 among both vaccinated and unvaccinated participants, though variation in neutralization efficacy was observed among different virus variants. These findings emphasize the importance of monitoring immune responses to track population-level immunity and guide future vaccination strategies.

Introduction. The rapid spread of coronavirus infection COVID-19 among the population of many countries around the world has contributed to the emergence of many genetic variants of SARS-CoV-2. Compared to previous coronavirus variants, the new Omicron variants have shown a noticeable degree of mutation. Virus inactivation is one of the most important steps in the development of inactivated vaccines. The chemical inactivation agents currently used are β-propiolactone and formaldehyde, but there is no uniform standard for designing and specifying the inactivation process. Objective. Evaluation and comparison of the effectiveness of chemical inactivation of two agents, formaldehyde and β-propiolactone against immunogenicity of the Omicron variant of the SARS-CoV-2 virus. Materials and methods. Nasopharyngeal swabs were used to obtain the SARS-CoV-2 Omicron variant virus. Vero cell culture was used to isolate, reproduce, titrate the virus, and perform a neutralization reaction. The kinetics of studying the inactivation of the virus by chemical agents such as formaldehyde and β-propiolactone was carried out. Results. Studies have been conducted to comparatively evaluate the effectiveness of chemical agents used to inactivate the SARS-CoV-2 virus of the Omicron variant, planned for use in the production of an inactivated whole-virion vaccine. Formaldehyde and β-propiolactone were used as inactivation agents in concentrations of 0.05, 0.1, 0.5% of the total volume of the virus suspension. It has been established that complete inactivation of the virus by formaldehyde in the concentrations used at a temperature of 37 °C occurs within up to 2 hours, and when using beta-propiolactone, within up to 12 hours. Conclusion. Inactivated virus samples have different antigenic activity depending on the concentration of the inactivation agents used. The most pronounced antigenic activity is manifested in samples of the pathogen that were treated with an inactivation agent at a mild concentration of 0.05%. Increasing the concentration of inactivation agent by 5 or more times leads to a significant decrease in the antigenicity of the SARS-CoV-2 virus. With the inactivation modes used, the loss of biological activity of the virus occurs faster and antigenicity is retained largely when treated with formaldehyde.