Objectives: The aim of our study was to investigate if there is a difference in the presence of symptoms in different phases of COVID-19. Additionally, we explored potential differences in SARS-CoV- 2 variants regarding their disease severity. Material and Methods: The study was designed as a retrospective cohort study, conducted at the REGIOMED Hospital in Coburg, Bavaria, Germany. Patients that had a positive SARS-CoV-2 PCR-test result and were hospitalized at the REGIOMED hospital in Coburg from 03/2020 until 03/2022 were included. Based on data delivered from the Robert Koch Institute, patients are divided into respective study groups depending on the prevalent SARS-CoV-2 variant at the time of their positive PCR-result. Results: The study presented significant differences in the age distribution across different phases, as well as differences in age between males and females, but no significant gender distribution across phases. A significant difference could also be seen in the presence of symptoms across different phases. The average age in asymptomatic males was 73 years and in symptomatic males 72.5 years, but with no significant correlation. In contrast, significant results were seen in females. A significant relationship between outcome and phase could be proven, with Phase 1 showing the highest mortality. Phase 2 shows the highest percentage of cases admitted to the ICU, indicating a significant association between phases and ICU status, which could also be proven for the association between outcome and ICU status. An analysis of the outcome in correlation with immunization status showed significantly that nonimmunized individuals have an increased mortality and lower discharge rates compared to immunized individuals. The mortality in immunized and non-immunized individuals also correlates with Phase 1 and 4 but is insignificant for Phase 2 and 3. Oxygen requirements differed across the Phases, yielding significant results. The general duration of hospitalization differed significantly across phases, with Phase 1 having the highest mean duration of hospitalization, whereas Phase 4 the shortest. Conclusion: The SARS-CoV-2 variants differ in their presentation of symptoms as well as in disease severity, presenting differences in the duration and type of hospitalization, oxygen requirements and outcome.