Health Information Portal (HIP)

Philadelphia Influenza Surveillance Updates: PDPH tracks influenza activity in Philadelphia, especially severe influenza disease. Providers should report all hospitalized influenza cases, influenza deaths in children, and influenza outbreaks in closed settings like long-term care facilities and shelters.

Week 22: Influenza diagnoses at local emergency departments and positive detections of influenza A at select local hospital laboratories remained low. Detections for influenza B further decreased during week 22, consistent with the past several weeks. Data from all facilities are complete from Week 8 2025 forward. Twenty-nine influenza outbreaks in long-term care facilities have been reported and confirmed (≥ 1 case of laboratory-confirmed flu reported in a long-term care facility) so far this season.

Week 22 Report: Click here to download the last weekly report of influenza activity (May 25, 2025 through May 31, 2025) in a printable format.

State and National Influenza Surveillance Updates:

Pennsylvania: As of May 31, 2025, the Pennsylvania Department of Health (PADOH) reported influenza activity is low. Activity levels in PA are based on laboratory-confirmed influenza cases. Please note that PADOH respiratory virus summaries will be paused until next season or if there is an unexpected increase. For more information, please visit: https://www.pa.gov/en/agencies/health/diseases-conditions/infectious-disease/respiratory-viruses/respiratory-virus-dashboard.html.

United States: As of May 31, 2025, the CDC reported that influenza activity remains low. In week 22, clinical laboratories reported 809 (2.0%) of 39,834 specimens tested positive for influenza, 33.1% of which were influenza A. Of influenza A specimens subtyped at public health labs, 86.2% have been subtyped as H1N1 and 13.8% as H3N2. In week 22, 53 of the 55 jurisdictions with sufficient data reported minimal influenza activity, including minimal activity reported in Pennsylvania. Activity levels were calculated from outpatient data reported to ILINet. For more information, please visit: https://www.cdc.gov/fluview/surveillance/2025-week-21.html.