Samples collected for PCR from recipient animals tested positive in 5 out of 6 cases, while the virus was isolated from 4 of 6 animals. The clinical signs exhibited by recipient animals were mostly moderate in nature with only one severe case. To our knowledge, this is the first time that transmission of LSDV by three Stomoxys species has been demonstrated, and their role as mechanical vectors of LSDV is indicated.
A new inactivated whole-virion QazCovid-in® vaccine against COVID-19 was developed from SARS-CoV-2 isolated in Kazakhstan, inactivated by formaldehyde, and adjuvanted with aluminium hydroxide. Phase 1 and 2 clinical trials aimed at assessing the vaccine's safety, immunogenicity, and the duration of immunity induced by the QazCovid-in® vaccine after one or two immunisations. From 23.09.2020 to 19.03.2021 we performed a randomised, single-blind, placebo-controlled phase 1 clinical trial and from 18.10.2020 to 17.04.2021 an open-label phase 2 clinical trials of the QazCovid-in® vaccine with a 6 months follow-up at a single centre in Almaty, the Republic of Kazakhstan. Eligible healthy adults aged 18 years and older with no history of laboratory-confirmed SARS-CoV-2 infection were randomly assigned to the treatment groups using a computerised randomisation scheme generator. In the phase 1 clinical trial, two doses of the vaccine (5 μg each) or placebo (0·9% NaCl) were administered intramuscularly to 44 subjects aged 18–50 years, 21 days apart. In the phase 2 trial, 200 healthy participants were randomised into four equal-sized groups according to the age (18–49 or ≥50 years) and either single (day 1) or double (day 1 and 21) vaccination protocol. The primary outcomes were safety and tolerability. The secondary outcome was immunogenicity. The cellular response was measured by a whole-blood cytokine release assay (phase 1 only). The trials were registered with ClinicalTrials.gov NCT04530357. The QazCovid-in® vaccine was safe and well-tolerated and induced predominantly mild adverse events; no serious or severe adverse events were recorded in both trials. In the phase 1 trial, the percentage of subjects with a fourfold increase of antibody titres (sero conversion) in MNA was 59% after one vaccine dose and amounted to 100% after two doses. Neutralizing antibody titres reached the geometric mean titre (GMT) of 100 after administration of two doses. A statistically significant increase in the levels of pro-inflammatory cytokines after vaccination indicated the Th1-biased response. On day 180, 40% of placebo-treated subjects demonstrated a statistically significant increase in the levels of antibodies measured by both ELISA and MNA, which suggests the infection with SARS-CoV-2. In the phase 2 trial, 100% of subjects aged 18–49 years seroconverted for SARS-CoV-2 on day 21 after the first dose, as indicated by MNA yielding the GMTs of 32 or 30 in the one- and two-dose groups, respectively. Amongst ≥50-year-old subjects, the number of sero conversions in the two- and one-dose groups on day 21 was 94% and 92% with the respective GMTs of 25 and 24. After the second dose, the sero conversion rate reached 100%; however, the GMT was significantly lower when compared with the corresponding value measured in subjects aged 18–49 years (83 vs 143). In both trials, specific antibodies were detected in MNA and ELISA on study day 180, but the titres dropped in comparison to day 42. The results of this study serve as the rationale for the phase 3 study. The QazCovid-in® vaccine is safe and well-tolerated and promotes pronounced humoral immunity which lasts for at least 6 months after double intramuscular immunisation.
We generated novel, effective candidate vaccine against Brucella abortus based on recombinant influenza viruses expressing the Brucella ribosomal protein L7/L12 or outer membrane protein (Omp)-16 from the NS1 open reading frame. The main purpose of this work was to evaluate the safety, immunogenicity and protectiveness of vaccine candidate in laboratory animals.
Vaccination remains the primary measure to prevent the spread of the SARS-CoV-2 virus, further necessitating the use of effective licensed vaccines. From Dec 25, 2020, to July 11, 2021, we conducted a multicenter, randomised, single-blind, placebo-controlled phase 3 efficacy trial of the QazCovid-in® vaccine with a 180-day follow-up period in three clinical centres in Kazakhstan. A total of 3000 eligible participants aged 18 years or older were randomly assigned (4:1) to receive two doses of the vaccine (5 μg each, 21 days apart) or placebo administered intramuscularly. QazCovid-in® is a whole-virion formaldehyde-inactivated anti-COVID-19 vaccine, adjuvanted with aluminium hydroxide. The primary endpoint was the incidence of symptomatic cases of the SARS-CoV-2 infection confirmed by RT-PCR starting from day 14 after the first immunisation. The trial was registered with ClinicalTrials.gov NCT04691908. The QazCovid-in® vaccine was safe over the 6-month monitoring period after two intramuscular immunisations inducing only local short-lived adverse events. The concomitant diseases of participants did not affect the vaccine safety. Out of 2400 vaccinated participants, 31 were diagnosed with COVID-19; 43 COVID-19 cases were recorded in 600 placebo participants with onset of 14 days after the first dose within the 180-day observation period. Only one severe COVID-19 case was identified in a vaccine recipient with a comorbid chronic heart failure. The protective efficacy of the QazCovid-in® vaccine reached 82·0% (95% CI 71.1–88.5) within the 180-day observation period. Two immunisations with the inactivated QazCovid-in® vaccine achieved 82·0% (95% CI 71.1–88.5) protective efficacy against COVID-19 within a 180-day follow-up period. The work was funded by the Science Committee of the Ministry of Education and Science of Kazakhstan within the framework of the Scientific and Technical Program “Development of a vaccine against coronavirus infection COVID-19”. State registration number 0.0927.
Tuberculosis is a major global threat to human health. Since the widely used BCG vaccine is poorly effective in adults, there is a demand for the development of a new type of boost tuberculosis vaccine. We designed a novel intranasal tuberculosis vaccine candidate, TB/FLU-04L, which is based on an attenuated influenza A virus vector encoding two mycobacterium antigens, Ag85A and ESAT-6. As tuberculosis is an airborne disease, the ability to induce mucosal immunity is one of the potential advantages of influenza vectors. Sequences of ESAT-6 and Ag85A antigens were inserted into the NS1 open reading frame of the influenza A virus to replace the deleted carboxyl part of the NS1 protein. The vector expressing chimeric NS1 protein appeared to be genetically stable and replication-deficient in mice and non-human primates. Intranasal immunization of C57BL/6 mice or cynomolgus macaques with the TB/FLU-04L vaccine candidate induced Mtb-specific Th1 immune response. Single TB/FLU-04L immunization in mice showed commensurate levels of protection in comparison to BCG and significantly increased the protective effect of BCG when applied in a “prime-boost” scheme. Our findings show that intranasal immunization with the TB/FLU-04L vaccine, which carries two mycobacterium antigens, is safe, and induces a protective immune response against virulent M. tuberculosis.
12 August 2022 in Human Vaccines & Immunotherapeutics
This article describes the results of a preclinical safety and immunogenicity study of QazCovid-in®, the first COVID-19 vaccine developed in Kazakhstan, on BALB/c mice, rats, ferrets, Syrian hamsters and rhesus macaques (Macaca mulatta). The study’s safety data suggests that this immunobiological preparation can be technically considered a Class 5 nontoxic vaccine. The series of injections that were made did not produce any adverse effect or any change in the general condition of the model animals’ health, while macroscopy and histology studies identified no changes in the internal organs of the BALB/c mice and rats. This study has demonstrated that a double immunization enhances the growth of antibody titers as assessed by the microneutralization assay (MNA) and the enzyme-linked immunosorbent assay (ELISA) in a pre-clinical immunogenicity test on animal models. The best GMT results were assessed in MNA and ELISA 7 days after re-vaccination; however, we noted that GMT antibody results in ELISA were lower than in MNA. A comparative GMT assessment after the first immunization and the re-immunization identified significant differences between model animal groups and a growth of GMT antibodies in all of them; also, differences between the gender groups were statistically significant. Moreover, the most marked MNA immune response to the QazCovid-in® vaccine was seen in the Syrian hamsters, while their SARS-CoV-2-specific antibody activity as assessed with ELISA was the lowest.