The study will include healthy volunteers aged 12-17 years inclusive. Volunteers will be recruited in at least two clinical centers. Teams will be divided into subgroups to ensure the safety of volunteers during hospitalization amid the ongoing pandemic.~Stage 1 (Phase I-II) - 100 volunteers will be included in two dosing groups (50 in each group), a sufficient number of volunteers should be screened (no more than 7 days before inclusion in the study). To ensure the required number of volunteers who have completed screening procedures (pre-screening procedures can be organized).~The conditions of the study were the selection of doses (administration of the drug and observation for 48 hours) in a hospital setting, the rest of the visits were outpatient.~It is planned to start the study with a dose of 1/10 of the full adult dose. Volunteers will be hospitalized the day before vaccination. It is allowed to carry out screening procedures the day before vaccination in a hospital setting, subject to the prior approval of the volunteer based on the results of pre-screening. The first dose will be administered on day 1. After that, the volunteer will be monitored in the hospital for 48 hours. on days 3 and 7, a telephone consultation will be held. With a favorable safety profile after 7 days after the 1/10 dose, the Principal Investigators present a consolidated decision to escalate the dose to 1/5 of the adult dose on ICMD.~The transition to the next stage is planned on the basis of the report on the safety and tolerability of ILS on the 28th day after the introduction of the first component. The selected dose will be determined based on the immunogenicity scores at day 28, which should be consistent with the immunogenicity in adults after receiving the full dose of ILP.~Stage 2 (Phase III) - 3000 volunteers to be randomized to two groups - active drug and placebo in a ratio of 4: 1. Volunteers will receive the drug at the dose selected in the first phase. Research is carried out on an outpatient basis.~The randomization of research subjects will be carried out in two age strata: 12-14 years old and 15-17 years old.~The intramuscular vaccine will be administered at vaccination visits # 2 and # 3 (Day 1 and Day 21 ± 2) on an outpatient basis. After vaccination, TMK will be carried out for 2 days.~Follow-up visits # 4 (28 ± 2), 5 (42 ± 4), 6 (90 ± 7) and 7 (180 ± 14); TMK for 270 ± 14 and 365 ± 14 days.~Additionally historical control data will be used (data from phase III clinical trials of efficacy, safety and immunogenicity obtained during their evaluation in a sample of adult volunteers aged 18-21 years);~The duration of study participation for one subject will be 365 ± 14 days after the first dose of vaccine, during which each subject will undergo a screening visit, two hospitalizations for drug administration, five face-to-face visits to the investigator, and telephone contacts with the investigator.~The data of research subjects will be collected using electronic forms of individual registration cards, as well as using electronic questionnaires (diaries) filled in by research subjects.
Double-blind, placebo-controlled study with open dose selection period for safety assessment, tolerance and immunogenicity of the drug GamKOVID-Vac M, a combined vector vaccine for prevention of coronavirus infection caused by the virus SARS-CoV-2 in adolescents