1945. Effects of COVID-19 Vaccines on Outcomes Among Hospitalized COVID-19 Patients

Abstract Background After COVID-19 vaccinations, breakthrough infections appear to be of public health concern. There is limited data regarding clinical effectiveness vaccination. Our aim was determine the differences in outcomes among unvaccinated versus vaccinated patients who required hospitalization. Methods This a retrospective cohort study hospitalized between 7/25/21 and 9/6/2021. Previously infected were excluded. The classified as fully vs. (CDC guidelines). primary outcome included need for advance oxygen therapy (high flow nasal cannula, non-invasive ventilation, mechanical ventilation), ICU admission, or 28-day all-cause mortality. We performed subgroup analysis according immunocompetent status older age (≥65 years). Results enrolled 207 patients, stratified (n=147 [71%]) (n=60 [29%]). Unvaccinated younger (median 58 71 years old, p< 0.001) more likely require (n=105[71%] n=35[58%], p=0.07) compared patients. reach (n=59 [40%] n=16 [26%], p=0.08) when analyses revealed that had higher rates ≥65 old ( n=27/46 [58.7%] n=13/37 [35.1%], p=0.047), (n=57/139 [41%] 13/53 [24.5%]) both groups combined (n=22/39 [56%] 11/38 [28.9%], p=0.021), respectively. Conclusion represented largest proportion therapy. aged ≥ 65 worse Further studies are needed identify unmeasured characteristics may associated with poor outcomes. Disclosures All Authors: No reported disclosures.