A framework for classifying disease trends applied to influenza-associated hospital admissions in the United States

We built a framework for categorizing week-to-week increases or decreases in seasonal influenza hospitalizations aiding data interpretation in the context of past seasons. Using Influenza Hospitalization Surveillance Network (FluSurv-NET) data, we established thresholds for weekly hospitalization rate differences and applied them to the 2022/23 and 2023/24 influenza seasons from the National Healthcare Safety Network. While the number of weeks categorized as stable was consistent across seasons, more large increases and decreases were observed in 2022/23. This metric captures hospitalization rate changes and contextualizes the current season relative to past influenza trends, facilitating trend assessment.