2.4. Procedures
CoviVac vaccine (manufactured by the Chumakov FSC R&D IBP RAS as described previously [In the 18–60 age cohort, the vaccine was injected twice at 14-day intervals. Participants were observed for any AEs for 30 min following the administration of each dose, and then daily until Day 15–17 (1–3 days after the 2nd vaccination), with subsequent follow-up visits at Days 20 (only for Stages 1 and 2), 28–31 and 42–45 (for all Stages). Self-recording of AEs by participants was performed using diaries. During the visits, vital signs measurement and physical examination were performed. Neurological assessment was performed before each vaccination, 3 days after each vaccination and 28 days after the 2nd vaccination. Urine and blood samples were collected at screening and days 3, 7, 10, 14, 17, 20, 28 and 42 after the 1st vaccination for hematological and biochemical analysis and immunological tests (at Stage 3). ECG was carried out at screening and once on days 2–6 after the 1st vaccination.In the 60+ age cohort, the vaccine was injected three times with 21 days intervals. Participants were observed at clinical sites for any AEs for at least 30 min following the administration of each dose with subsequent phone calls 5–8 h later on the same day, at scheduled appointments 2, 7 and 14 days after each vaccination and also 21 days after the 3rd vaccination. Reporting of AEs by participants was performed using self-observation diaries. At screening, on each day of vaccination and two days after each vaccination, and 21 days after the 3rd vaccination, vital signs measurement and physical examination were performed. Serum samples were obtained from all participants five days before the 1st vaccination and then on Day 42 (21 days after 2nd vaccination) and Day 63 (21 days after 3rd vaccination) for immunogenicity assessment. Nasopharyngeal swabs for SARS-CoV-2 PCR test were performed at screening, on the days of the 2nd and 3rd vaccination and 21 days after the 3rd vaccination. Urine and blood samples were collected at screening and days 2, 23, 42, 44 and 63 after the 1st vaccination for hematological and biochemical analysis.