Influenza Vaccination in the Emergency Department: Are Our Patients at Risk?

Background: Influenza is responsible for substantial morbidity and mortality annually. Vaccination strategies target high-risk patients. The percentage of Emergency Department (ED) patients at high risk is largely unknown. Objectives: The percentage of patients at high risk for influenza was determined and compared to the United States (US) population. Methods: Medical records of a convenience sample of all patients presenting to the ED of a university-affiliated hospital in Tucson, Arizona from February 1–7, 2006 were reviewed (n = 1359). Patients were stratified as 1) at high risk for influenza or its complications, 2) health care workers (HCW), household contacts of high-risk patients, and other target populations, and (3) otherwise healthy adults. Additionally, vaccination status and prior ED utilization within that season's vaccination period was determined. Results: Of all patients presenting to the ED, 41.5% were at high risk for influenza or its complications (US 30.8%, p < 0.001). Of all ED patients, 10.8% were household contacts, HCWs, or in another target group (US 42.8%, p < 0.001). Of high-risk ED patients, 43.5% had been vaccinated that season (US 47.1%, p < 0.001) and 13.7% had had at least one visit to the ED within the preceding 3 months. Conclusion: There is a higher percentage of patients at high risk for influenza in the ED population than the general US population. The ED may be a novel location in which to effectively identify and immunize high-risk individuals. Benefits to ED vaccination may include subsequent reductions in mortality and morbidity as well as a decrease in ED utilization and hospitalization for influenza and its complications.