COVID-19 in the Republic of Belarus: pandemic features and the interim safety and efficacy assessment of the Gam-COVID-Vac vaccine

ObjectiveTo study the COVID-19 pandemic features among the population of the Republic of Belarus from February 2020 to September 2021 and assess the safety (tolerance) and epidemiological efficacy of the Gam-COVID-Vac vaccine (Sputnik V). Materials and methodsA retrospective analysis of COVID-19 cases in the Republic of Belarus from the beginning of registration (February 28, 2020) to September 12, 2021 was performed. To assess the COVID-19 case detection dynamics, official registration data available on the website of the Ministry of Health of the Republic of Belarus were used. Vaccine safety (tolerance) and efficacy were assessed in an observational study. Safety (tolerance) was assessed by presence/absence of adverse reactions: general and local ones. The efficacy rate (E) and the epidemiological efficacy index (K) was calculated according to the formula: E(%)=100*(b-a)/b, K=b/a. ResultsOur data show that The COVID-19 pandemic in the Republic of Belarus is characterized by successive development stages: the first is the absence of COVID-19 cases in the country; the second is the registration of individual infection cases that came from abroad followed by local pathogen spread among the countrys population; the third is a local spread of COVID-19 among individuals who had contact with infected people; the fourth is the detection of cases where patients had no history of exposure to COVID-19 patients. As of calendar week 26, 2021 Delta variant of SARS-CoV-2 has become the prevalent in the country. Follow-up results in January-August 2021 showed that the Sputnik V vaccine was well tolerated, with 80,832 adverse reactions reported (2.99% (95% CI 2.9-3.0) of the total number of vaccine doses administered). In terms of severity, adverse reactions were mild (91.4% (95% CI 91.2-91.6)) and moderate (8.6% (95% CI 8.6-8.8)). The epidemiological efficacy rate was 96.3%, the epidemiological efficacy index was 26.7. Thus, the results obtained testify to high prophylactic efficacy of the Sputnik V vaccine. ConclusionsThe COVID-19 pandemic in the Republic of Belarus is characterized by successive development stages: from no cases in early 2020 to detected cases where most individuals had no history of contact with COVID-19 patients; periods of rising and falling incidence. The Sputnik V vaccine has demonstrated a high safety profile and epidemiological efficacy throughout mass vaccination in the Republic of Belarus.