Aim. To assess the effectiveness of vaccination against Omicron and Delta variants according to the international registry "Dynamics Analysis of Comorbidities in SARS-CoV-2 Survivors" (AKTIV-4). Material and methods. The AKTIV-4 registry included men and women over 18 years of age with a diagnosis of coronavirus disease 2019 (COVID-19) (oropharyngeal and nasopharyngeal swabs, SARS-CoV-2 antibody titers, typical computed tomography performance), undergoing hospital treatment. A total of 3543 patients from 25 medical centers in 7 countries (the Russian Federation, the Republic of Armenia, the Republic of Belarus, the Republic of Kazakhstan, the Kyrgyz Republic, the Republic of Moldova, and the Republic of Uzbekistan) were included in the AKTIV-4 registry. Results. The clinical status of patients from the AKTIV-4 registry was more severe than in the AKTIV-1 and AKTIV-2 registries. Patients in the AKTIV-4 registry were older than patients in the AKTIV-1 registry. The inhospital mortality rate in patients in the AKTIV-4 registry was higher (8,41%, p