Respiratory Virus Activity — United States, July 1, 2024–June 30, 2025

Respiratory viruses are common causes of upper and lower respiratory tract illness and can also result in hospitalization and death. CDC conducts national surveillance using multiple systems to monitor ongoing and seasonal changes in the activity of selected respiratory viruses. This report summarizes U.S. trends in endemic respiratory virus activity during July 2024-June 2025. For SARS-CoV-2 and respiratory syncytial virus (RSV), national and regional trends; population-based hospitalization rates; vital records death counts; and preliminary estimates of associated illnesses, outpatient visits, hospitalizations, and deaths are described, as well as genetic characterization of circulating SARS-CoV-2 viruses. Some viruses, including SARS-CoV-2, showed bimodal peaks in positive laboratory test results, whereas others, including RSV and influenza viruses, were characterized by a single peak. The highest COVID-19-associated hospitalization rates were reported among adults aged ≥75 years (932.6 per 100,000 persons), infants aged