Introduction: Coronavirus are common pathogens that primarily affect the human respiratory system. New coronavirus SARS-CoV-2 has caused a global pandemic since the beginning of 2020. So far, COVID-19 has been confirmed in 543 million cases of which 6.33 million have been fatal. ----- Objective: The purpose of the research is to compare disease outcomes in hospitalized patients with COVID-19 in relation to vaccination status. An additional goal is to determine which factors are important for the outcome in patients with COVID-19, such as comorbidities, age and gender. ------ Subjects and methods: This is a retrospective cohort study. The cohort consists of 180 patients who were treated for COVID-19 at the Viral Hepatitis Department of the "Fran Mihaljević" Infectious Diseases Clinic in the period from August 1, 2021. until 28.2. 2022. In the research, we used a departmental prospectively designed database with basic data on hospitalized patients. ----- Results: In total, 180 patients who were treated for COVID-19 in the hospital were included in the study. The average age of this population was 62.08 ± 16.52 years, 108 of them were male, while 72 were female. For research purposes, the population was divided into unvaccinated and vaccinated. The unvaccinated population included 128 patients, 67 men and 61 women, average age 58.27 ± 16.91 years. The vaccinated population was further divided into 3 groups depending on the number of doses received. 46 patients received two doses of the vaccine, average age 71.22 ±11.29. year. The vaccinated population is older and has a higher proportion of men compared to the unvaccinated population, has a higher proportion of patients with comorbidities, especially arterial hypertension (78.26% vs 45.31%), diabetes (26.09% vs 16.41%) and other cardiovascular diseases (34.78% vs 11.72%). Overall, mortality was higher in the vaccinated population (17.39%) compared to the unvaccinated (13.28%). The incidence of pulmonary artery thrombosis was higher among the unvaccinated (17.97%) compared to the vaccinated (6.52%). Mortality in the oldest age groups (over 80 years) was 54% lower in the vaccinated population (40%) compared to the unvaccinated population (61.54%). The population of all the deceased had a significantly higher prevalence of cardiovascular comorbidities (50%) compared to the survivors (12.34%). -----Conclusion: Older age and comorbidities are recognized as the most important risk factors for the development of a severe and/or lethal form of COVID-19. The presence of cardiovascular comorbidities negatively affects the outcome. The unvaccinated population has a worse long-term outcome and later complications related to the respiratory system. The vaccine has a more favorable effect on the outcome, especially if the time elapsed since vaccination is shorter, which justifies the need for booster doses. This especially applies to older age groups, which are also the most vulnerable.