Mass immunization of the population is a fundamental measure to prevent the spread of infection caused by the SARS-CoV-2 virus. Published Russian and foreign data demonstrate the high effectiveness of the Russian Gam-COVID-Vac vaccine. However, the effectiveness of the vaccine against new coronavirus COVID-19 (hereinafter referred to as NCV) at the population level in Khabarovsk region has not been previously studied.
OBJECTIVE
To analyze the effectiveness of the Gam-Covid-Vac vaccine in real-world practice in healthcare institutions of Khabarovsk region to prevent symptomatic cases of NCI.
MATERIAL AND METHODS
A comprehensive data analysis was performed on 154.144 records from the regional segment of the Federal registry of COVID-19 vaccinated population compared to 55.578 records in the regional segment of the Federal registry of COVID-19 infected population. During the study, parametric and nonparametric methods were used, relative and mean values and their errors were calculated, and significance was determined using MS-Office 2017 and Statistica 10.0 software. The values were considered significant at p<0.05. The calculations were made taking into account the adult population of Khabarovsk region.
RESULTS
Immunization results of 154.144 subjects were studied, 88.324 (57.30±0.13%) were over 50 years old. A total of 145.270 (94.24±0.06%) subjects were fully vaccinated, 751 (0.49%) of them became infected. The maximum incidence values (200.00±40.00 ‰) were recorded in those over 50 years old who received only the first vaccine component more than six months ago, while the minimum values were recorded in those under 50 years old who received both vaccine components (2.04±0.17‰). In those vaccinated, who got infected with NCI, 83.0% had a mild disease; in 17.0%, a moderate severity course with lung damage was registered, which was considered CT grade 2 in 29.4% of cases, and CT grade 1 in 70.6% of cases. The effectiveness of the Gam-COVID-Vac vaccine to prevent symptomatic NCI was 98.4%, and 100.0% to prevent the severe course of the disease and death. In addition, the use of the vaccine in Khabarovsk region from October 1, 2020 to June 30, 2021 (a total of 15.1% of the adult population of the region was vaccinated) resulted in a 10-fold reduction in the incidence of NCI.
CONCLUSION
The effectiveness of Gam-COVID-Vac vaccine in real-world practice is demonstrated. Broader vaccination of the Khabarovsk region population will further reduce the incidence of NCI in the region.
