Objectives. This study aimed to compare the characteristics of fully and partially vaccinated or unvaccinated coronavirus disease 2019 (COVID-19) patients who were hospitalised in a population of 220,000 habitants. Methods: Retrospective, observational, and population studies were conducted on patients who were hospitalised due to COVID-19 from March to October 2021. We assessed the impact of vaccination and other risk factors through Cox multivariate analysis. Results: A total of 500 patients were hospitalised, among whom 77 (15.4%) were fully vaccinated, 86 (17.2%) were partially vaccinated, and 337 (67.4%) were unvaccinated. Fully vaccinated (FV) patients were older and had a higher Charlson index than those of partially vaccinated and unvaccinated patients (NFV). Bilateral pneumonia was more frequent among NFV (259/376 (68.9%)) than among FV patients (32/75 (42.7%)). The former had more intensive care unit admissions (63/423) than the latter (4/77); OR: 2.80; CI (1.07–9.47). Increasing age HZ: 1.1 (1.06–1.14)) and haematological disease at admission HZ: 2.99 (1.26–7.11)) were independent risk factors for higher mortality during the first 30 days of hospitalisation. The probability of an earlier discharge in the subgroup of 440 patients who did not die during the first 30 days of hospitalisation was related to age (older to younger: HZ: 0.98 (0.97–0.99)) and vaccination status. Conclusions: Among the patients hospitalised because of COVID-19, complete vaccination was associated with less severe forms of COVID-19, with an earlier discharge date. Age and haematological disease were related to a higher mortality rate during the first 30 days of hospitalisation.

(1) Background: COVID-19 has evolved during seven epidemic waves in Spain. Our objective was to describe changes in mortality and severity in our hospitalized patients. (2) Method: This study employed a descriptive, retrospective approach for COVID-19 patients admitted to the Hospital de Fuenlabrada (Madrid, Spain) until 31 December 2022. (3) Results: A total of 5510 admissions for COVID-19 were recorded. The first wave accounted for 1823 (33%) admissions and exhibited the highest proportion of severe patients: 65% with bilateral pneumonia and 83% with oxygen saturation under 94% during admission and elevated levels of CRP, IL-6, and D-dimer. In contrast, the seventh wave had the highest median age (79 years) and comorbidity (Charlson: 2.7), while only 3% of patients had bilateral pneumonia and 3% required intubation. The overall mortality rate was 10.3%. The first wave represented 39% of the total. The variables related to mortality were age (OR: 1.08, 1.07–1.09), cancer (OR: 1.99, 1.53–2.60), dementia (OR: 1.82, 1.20–2.75), the Charlson index (1.38, 1.31–1.47), the need for high-flow oxygen (OR: 6.10, 4.94–7.52), mechanical ventilation (OR: 11.554, 6.996–19.080), and CRP (OR: 1.04, 1.03–1.06). (4) Conclusions: The variables associated with mortality included age, comorbidity, respiratory failure, and inflammation. Differences in the baseline characteristics of admitted patients explained the differences in mortality in each wave. Differences observed between patients admitted in the latest wave and the earlier ones suggest that COVID-19 has evolved into a distinct disease, requiring a distinct approach.

(1) Background: Since the onset of the SARS-CoV-2 pandemic, seven epidemic waves have been described in Spain. Our objective was to study mortality and severity, and associated factors in our hospitalized patients; (2) Method: Retrospective cohort study was conducted on COVID-19 patients admitted to the Hospital de Fuenlabrada (Madrid, Spain) from the beginning of the pandemic until December 31, 2022; (3) Results: A total of 5,510 admissions for COVID-19 were recorded. First wave accounted for 1,823 (33%) and exhibited the highest proportion of severe patients (lowest mean oxygen saturation, 88.2%; elevated levels of CRP, IL-6, D-dimer and ferri-tin), but a below-average percentage of intubated patients (5% vs. 6.5%). Overall mortality rate was 10.3%, higher during the first wave (11.5%) and the two winter waves (third: 11.3%, sixth: 12%), although the first wave represented 39% of the total. Variables associated with mortality were age (OR 1.08,1.07-1.09), need for high-flow oxygen (OR 6.10,4.94-7.52), oncological disease (OR 1.88,1.53-2.60), dementia (OR 1.82,1.2-2.75), Charlson index (OR 1.38,1.31-1.47), and maxi-mum IL-6 levels (OR 1.001,1.000-1.001); (4) Conclusions: Variables associated with mortality in-cluded age, comorbidity, respiratory failure, and inflammation. Differences on baseline charac-teristics of patients admitted explained differences on mortality in each wave