The effect of vaccination against the COVID-19 on the course and outcomes of a new coronavirus infection: a retrospective analysis of laboratory and clinical indicators of hospitalized patients

Abstract

BACKGROUND: The Gam-COVID-Vac vaccine was proven effective in preventing the severe course and adverse outcomes of COVID-19 during different periods of the pandemic. However, the effect of vaccination on laboratory marker levels in hospitalized patients during the spread of the omicron variant of SARS-CoV-2 has not been sufficiently studied. AIM: To assess the effect of vaccination on the severity and outcomes of COVID-19 in hospitalized patients during the dominance of the SARS-CoV-2 omicron variant in Russia. MATERIALS AND METHODS: This case–control study included adult patients diagnosed with COVID-19 (U07.1) and hospitalized in infectious hospitals in Moscow between February 1, 2022, and July 31, 2022 (n=119). The main group included individuals vaccinated with two doses of Sputnik V vaccine (n=59). The control group included individuals who were not vaccinated (n=60). The median patient age was 66 [interquartile range, 41–66] years, and 58.8% were female. The chi-square test for categorical variables and the Mann–Whitney test for continuous variables were used for the analysis. P-values 0.05 were considered statistically significant. RESULTS: Viral pneumonia was less likely to develop in the vaccinated group than in the unvaccinated group (46.7% and 18.6%, respectively, p = 0.007). The proportion of patients without lung damage (0 CT-severity scores) in the vaccinated group (72.0%) was significantly higher than that in the unvaccinated group (42.9%) (p=0.003). In the vaccinated group, the levels of C-reactive protein on admission were lower (29.1 [7.4–68.6] mg/L and 75.1 [32.4–104.0] mg/L, p 0.001), and the highest level was recorded during hospitalization (38.2 [12.0–84.0] mg/L and 92.2 [45.3–137.4] mg/L, p 0.001). The D-dimer levels before discharge were lower in the group of patients vaccinated 6 months ago than in the unvaccinated group (157.0 [107.0–297.0] ng/mL and 316.0 [125.0–556.0] ng/mL, respectively, p = 0.014). The frequency of deaths in the control group (11.7%) was 6.9 times higher than that in the main group (1.7%) (p = 0.030). CONCLUSIONS: Completion of the primary vaccination course of Sputnik V vaccine resulted in lower levels of prognostic markers of severe COVID-19 (C-reactive protein and D-dimer) and a decrease in the frequency of pulmonary and fatal outcomes than in the unvaccinated group during the dominance of the omicron variant of SARS-CoV-2.