The California Department of Public Health (CDPH) Influenza Surveillance Program (CISP) is a collaborative effort between CDPH, the Centers for Disease Control and Prevention (CDC), Kaiser Permanente, California local health jurisdictions and the participating California sentinel providers and sentinel laboratories. Influenza surveillance in California is particularly important due to its coastal location with several ports of entry for flights and shipping from Asia. Annual influenza epidemics follow a winter seasonal pattern in the United States with typical activity peaking during late December to early February. CDPH obtains and analyzes clinical, and laboratory data year-round in an effort to determine the timing and impact of influenza activity and to determine how well circulating strains of the virus match those used in the current influenza vaccines.
Influenza surveillance season: Influenza surveillance seasons run from Week 40 through Week 39. Values include: 2001-2002, 2002-2003, 2003-2004, 2004-2005, 2005-2006, 2006-2007, 2007-2008, 2008-2009, 2009-2010, 2010-2011, 2011-2012, 2012-2013, 2013-2014, 2014-2015, 2015-2016, 2016-2017, 2017-2018, 2018-2019, 2019-2020.
Regions
Values:
- Bay Area: Includes Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Santa Cruz, Solano, and Sonoma counties California: All California counties
- Central: Includes Calaveras, Fresno, Inyo, Kings, Madera, Mariposa, Merced, Mono, Monterey, San Benito, San Joaquin, Stanislaus, Tulare, and Tuolumne counties
- Lower Southern: Includes Imperial, Orange, Riverside, San Bernardino, and San Diego counties
- Northern: Includes Alpine, Amador, Butte, Colusa, Del Norte, El Dorado, Glenn, Humboldt, Lake, Lassen, Mendocino, Modoc, Nevada, Placer, Plumas, Sacramento, Shasta, Sierra, Siskiyou, Sutter, Tehama, Trinity, Yolo, and Yuba counties
- Upper Southern: Includes Kern, Los Angeles, San Luis Obispo, Santa Barbara, and Ventura counties
Note: Not all counties in region have outpatient ILI data providers
Columns Description
- Season: Influenza surveillance season: Influenza surveillance seasons run from Week 40 through Week 39. (text)
- Weekending: Date of the last day included in the CDC MMWR Week (Saturday). Format MM/DD/YYYY. (number)
- Total_ILI: Number of outpatient visits for influenza-like illness (ILI). (number)
- Total_Patients_Seen: Total patients seen for any reason. (number)
- Percent_ILI: Percentage of patients that were due to influenza-like illness. (number)
- Number_Providers_Reporting: Number of providers reporting data during given week and region. (number)