Context Vaccination status has been shown to be linked to patient-centered outcomes in those with COVID-19. However, minimal data have explored the relationship between vaccination status and representation rates after receiving monoclonal antibodies (MABs) the Delta strain of severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) in a community setting. Objectives The authors sought to determine if there was a difference in patient-centered outcomes between those who were vaccinated and unvaccinated after the administration of casirivimab/imdevimab for mild-to-moderate COVID-19 during the time when the Delta strain was most prevalent. Methods A convenience sample of consecutive adults given casirivimab/imdevimab at either an outpatient infusion center or within the emergency department (ED) were included in analysis. Patient demographics, authorized-use qualifiers from the emergency use authorization (EUA), baseline vital signs at the time of infusion, representation rates to a healthcare provider within the hospital’s network, and any admissions to the hospital following infusion were all collected from the patient’s electronic medical record. Vaccination status was confirmed in both the patient’s electronic medical record and the Arizona State Immunization Information System (ASIIS). Analysis was conducted utilizing descriptive statistics, the Mann–Whitney U test for continuous data, and the chi-squared analysis for nominal data. Results In total, 743 patients were included in the study, with 585 being unvaccinated and 158 being vaccinated at the time of administration. Those in the vaccinated group were more likely to be older (60.0 vs. 55.0 years; p<0.001) and to have a history of diabetes (18.4% vs. 11.3%; p=0.02), hypertension (39.9% vs. 28.5%; p=0.006), immunosuppression (7.0% vs. 1.4%; p<0.001), and chronic kidney disease (7.0% vs. 3.4%; p=0.05). In the entire sample, 105 (14.1%) patients had an unexpected return visit to either the ED or urgent care at 28 days, with 17 (2.3%) requiring hospitalization. Patients who were vaccinated were more likely to represent for care after casirivimab/imdevimab infusion (20.3% vs. 12.5%; p=0.01), but no difference was noted in hospitalization rates between the two groups (18.8% vs. 15.1%; p=0.15). Conclusions MAB therapy with casirivimab/imdevimab for the outpatient treatment of mild-to-moderate COVID-19 was associated with a low rate of hospitalization. However, those who were vaccinated were more likely to present for unexpected return care at either the ED or urgent care within 28 days of the initial infusion.

Introduction Although there were several proposed treatments for patients that were hospitalized with COVID-19, outpatient treatments for those with mild to moderate illness were limited prior to the emergency use authorization (EUA) of virus-neutralizing monoclonal antibodies. To assess the efficacy of outpatient monoclonal therapy, the investigators assessed the seven, 14, and 28-day emergency department and hospitalization rates of adult patients given bamlanivimab for the treatment of COVID-19 at a community hospital. Methods A retrospective chart review was performed of all adult patients given bamlanivimab within the emergency department or an outpatient infusion center from December 2, 2020 through January 8, 2021 for the treatment of mild to moderate COVID-19. Patients were compared to a set of controls who would have qualified for bamlanivimab treatment prior to its authorization in reverse temporal order from November 30, 2020 through August 1, 2020. Abstracted data included patient demographics, allergic reactions, emergency department presentations, and hospitalizations at seven, 14, and 28 days post-infusion due to COVID-19 and any in-hospital mortality in those admitted with a COVID-19 complication. Results A total of 136 patients received bamlanivimab during the study period with none having an allergic reaction during infusion. In those who received bamlanivimab, 84 (61.8%) patients included were aged 65 years or older. At 28 days, there was a statistically significant reduction in emergency department visits in those who received bamlanivimab (20 vs 36 patients; p = 0.03) but not at seven days (12 vs 20 patients; p = 0.18) or 14 days (17 vs 28 patients; p = 0.11). No statistically significant difference in emergency department returns was noted in those aged 65 years or older at seven (eight vs eight patients; p = 0.70), 14 (11 vs 10 patients; p = 0.83), or 28 days (13 vs 14 patients, p = 0.46). A total of six (4.4%) patients were hospitalized at 28 days following the bamlanivimab infusion with five (83.3%) being aged 65 or older. No statistical difference was noted for decreased hospitalizations at seven (four vs five patients; p = 0.79), 14 (five vs nine patients; p = 0.32), or 28 days (six vs nine patients; p = 0.49) post-infusion. No patients suffered from in-hospital mortality after infusion with bamlanivimab. Conclusion Outpatient infusion of bamlanivimab reduced the incidence of those with mild to moderate COVID-19 requiring subsequent care through the emergency department at 28 days but not hospitalizations within this time frame. No statistical difference was noted in either emergency department visits or hospitalizations in those aged 65 or greater who were treated as an outpatient with bamlanivimab for mild to moderate COVID-19.