Quinlan ND, Werner BC, Novicoff WM, et al. - An analysis of influenza diagnoses using multiple administrative databases was designed to evaluate whether patients more susceptible to viral illness immediately following hip and knee arthroplasty. Researchers examined four large administrative datasets (Medicare 5% and 100% standard analytic files, Humana claims, and Mariner Database) to distinguish patients who had undergone total knee arthroplasty and total hip arthroplasty from 2005 to 2017. They characterized the influenza vaccination status of each patient applying the presence or absence of a code for vaccination. They recorded the incidence of an influenza diagnosis in both vaccinated and unvaccinated patients during peak influenza season following the date of surgery and compared to a cohort of vaccinated patients who did not undergo surgery. In patients who have recently undergone total joint arthroplasty, large administrative databases fail to display an elevated incidence of influenza. These findings are limited by the nature of large administrative datasets and the accuracy of coding for influenza, while the lack of signal in the data is reassuring. Future trials are needed to evaluate an individual patient’s postoperative risk for contracting a viral illness.