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 13: Influenza diagnoses at local emergency departments decreased for all age groups during week 13. Positive detections of influenza A at select local hospital laboratories continued to decrease during week 13 following the seasonal peak. Detections for Influenza B continued to increase during week 13. Data from all facilities are complete from Week 8 2025 forward. Twenty-seven 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 13 Report: Click here to download the last weekly report of influenza activity (March 16, 2025 through March 22, 2025) in a printable format.

State and National Influenza Surveillance Updates:

Pennsylvania: As of March 29, 2025, the Pennsylvania Department of Health (PADOH) reported Influenza activity is still elevated but continues to decrease. Activity levels in PA are based on laboratory confirmed influenza cases. 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 March 29, 2025, the CDC reported that influenza activity remains elevated nationally but continues to decrease. In week 13, clinical laboratories reported 6,725 (9.7%) of 69,263 specimens tested positive for influenza, 51.2% of which were influenza A. Of influenza A specimens subtyped at public health labs, 51.2% have been subtyped as H1N1 and 48.8% as H3N2. In week 13, 2 jurisdictions reported high levels of influenza activity. The remaining 52 jurisdictions with sufficient data reported minimal to moderate activity, including minimal activity reported in Pennsylvania and low activity reported in New Jersey. Activity levels were calculated from outpatient data reported to ILINet. For more information, please visit: https://www.cdc.gov/fluview/surveillance/2025-week-13.html.