Seasonal Influenza in Philadelphia
Philadelphia Seasonal Influenza Activity:     
Number of Lab-Confirmed Reports: 38*
Number of Hospitalized Cases: 10
Number of Deaths: 0
* These totals are collected from a subset of labs.

Last Updated (12/7/2019)

Current Recommendations
  • Annual influenza vaccine is recommended for ALL persons 6 months of age and older. Providers should offer influenza vaccination to all patients at every opportunity.
  • Healthcare worker influenza vaccination is recommended and endorsed by the Centers for Disease Control and almost every professional organization. Providers should be vaccinated to protect patients, themselves and their families.
  • Respiratory etiquette is also important during influenza season. Everyone should cover their cough and practice regular hand-washing, especially when symptomatic.
 Latest Updates on Seasonal Influenza
  • Influenza activity is currently characterized as WIDESPREAD in Pennsylvania (influenza outbreaks or increases in influenza-like illness cases or laboratory-confirmed influenza in at least half of a state's regions).

Health Alerts, Advisories, Notifications, and Updates

New Influenza Vaccine Requirement for Daycare Attendees: The Board of Health in Philadelphia passed a new regulation requiring flu vaccination for all children 6 months – 5 years old who attend any group child care facility in Philadelphia. Child care attendees need to receive a flu vaccine every year between September 1st and December 31st.

Vaccine Information

  • Influenza vaccination is the most effective tool available to prevent illness due to influenza. Getting vaccinated reduces the risk of flu-related doctor's visits, hospitalization, and death.
  • Anyone can receive an age-appropriate influenza vaccine except infants <6 months of age and people with history of a severe, life-threatening allergic reaction to flu vaccine or any flu vaccine ingredient. Most people with egg allergies can receive flu vaccines.
  • Flu vaccine is especially important for people who are at higher risk of serious complications from influenza including children <5 years, adults 65 years and older, pregnant women and people who have:
    • Asthma and other chronic lung diseases
    • Diabetes
    • Metabolic disorders
    • Immunocompromising conditions (i.e., HIV/AIDS, cancer) or who take immunocompromising medicines
    • Neurologic conditions
    • Obesity
    • Blood disorders like sickle cell diseases
  • Providers should continue to give influenza vaccine as long as influenza is still circulating in the community.

Surveillance                                                                                                                                                         Archive

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 49: Febrile/flu-like illnesses continued to increase among children ages 0-4 years. Thirty-eight positive specimens were reported from our sentinel hospital laboratory surveillance for influenza A and B during the same time period among the 6 participating laboratories, most of which (31) were influenza B. There were 10 reports of severe influenza (Philadelphia resident, positive by rapid test, PCR or culture, and hospitalized for = 24 hrs.) during this time frame, with 70% positive for Influenza B. There were no influenza outbreaks (= 1 case of laboratory confirmed influenza reported in a long term care facility) reported this week, with a total of 1 outbreak this season. No influenza-associated deaths have been reported. 

Current Report: Click here to download the last weekly report of influenza activity (from Dec. 1, 2019 through Dec. 7, 2019) in a printable format. 

Febrile/Flu-like Illnesses at Philadelphia Emergency Departments 2017-2018 Data Compared to 4 Year Historical Weekly Averages
Laboratory-based Surveillance for Influenza A: Philadelphia, 2013/2014 through 2017/2018 Seasons
Laboratory-based Surveillance for Influenza A: Philadelphia, 2013/2014 through 2017/2018 Seasons
Hospitalized Influenza Cases by Age Group
Weekly Counts of Hospitalizations by Flu Type

National and State Influenza Surveillance Updates: 


The Pennsylvania Department of Health (PADOH) has reported “widespread” influenza activity, which is defined by the CDC as outbreaks of laboratory-confirmed influenza or increases in influenza-like illness in at least half of the state. From 9/29/19 to 12/07/19, there have been 4,424 laboratory confirmed cases of influenza (positive by rapid test, PCR, or culture). The majority of influenza throughout the state has been identified as influenza B (3,285 reports, 74.3%). Six influenza related deaths have been reported thus far this season. For more information, please visit

United States

Widespread activity has increased to 23 states from 16, with higher ILI-activity in Southern states. The majority of specimens tested in clinical laboratories since week 40 have been positive for influenza B (2,353, 68.5%). CDC has antigenically characterized 16 B/Victoria and 18 A(H1N1) viruses and has found that 10 (62.5%) of B/Victoria and 18 (100%) of A(H1N1) viruses were antigenically similar to the cell-grown reference viruses in the current vaccine. Almost all (>99%) tested viruses show susceptibility to oseltamivir, zanamivir, baloxavir and peramivir. For more information, please visit