This clinical study is a prospective, single-center, open-label, non-comparative, non-randomized single-arm study. It will enroll adult subjects aged ≥ 18 years old with absence of active COVID-19 infection to be verified by the results of reverse transcription polymerase chain reaction (RT-PCR).~100 subjects meeting inclusion criteria are expected to be screened, 100 of them meeting eligibility criteria will receive one intramuscular injection of AZD1222 vaccine at 5×10^10 viral particles (nominal dose) and at least 90 subjects per one intramuscular injection of rAd26-S at (10±0.5) 1*10^11 viral particles with a 4-week interval on study days 1 and 29, respectively.~Duration of the subject participation in the study will be 6 months (180±10 days) from the day of administration of the first dose of AZD1222 vaccine. 10 visits are scheduled for each subject, 8 of them being obligatory personal visits to the study site.~Safety will be assessed for the duration of the study as follows:~Solicited adverse events (AEs) (local and systemic) will be assessed for 7 days following each vaccination (ie, on days 1-7 after the first vaccination and on study days 29-35 to account for AEs after second vaccination) at the study visits and based on the results of Subject Diary review.~Unsolicited AEs will be recorded within 29 days after administration of each dose of AZD1222/rAd26-S vaccine (i.e. on days 1-29 and on days 29 to 57).~Serious adverse events (SAEs) will be recorded from signing of the informed consent form through Day 180~Adverse events of special interest (AESI) will be documented from the first vaccination until day 180.~Immunogenicity will also be assessed throughout the study and include serological assay of levels of antibodies specific for Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen as well as level of seroconversion, tests for neutralising antibodies.~At least 100 subjects are expected to receive at least one dose of the study product in 1 study site on the territory of Republic Azerbaijan.
The purpose of the study is to assess safety and immunogenicity of heterologous booster vaccine containing combination of AZD1222 and rAd26-S (one of components of Gam-COVID-Vac vaccine) in adult subjects aged ≥ 18 years old to prevent COVID-19 spread.