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 18: Influenza diagnoses at local emergency departments increased slightly for adolescents, but continued to decrease for children < 5 years of age and adults during week 18. Positive detections of influenza A at select local hospital laboratories continued to decrease during week 18 following the seasonal peak. Detections for influenza B also decreased during week 18, 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 18 Report: Click here to download the last weekly report of influenza activity (April 27, 2025 through May 3, 2025) in a printable format.

State and National Influenza Surveillance Updates:

Pennsylvania: As of May 3, 2025, the Pennsylvania Department of Health (PADOH) reported influenza activity is low. 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 May 3, 2025, the CDC reported that influenza activity is low and continues to decline nationally. In week 18, clinical laboratories reported 1,814 (3.6%) of 50,071 specimens tested positive for influenza, 27.7% of which were influenza A. Of influenza A specimens subtyped at public health labs, 50.5% have been subtyped as H1N1 and 49.5% as H3N2. In week 18, all 55 jurisdictions with sufficient data reported minimal to low 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-18.html.