Influenza

Seasonal Influenza Surveillance

Each influenza season, Orange County Health Care Agency partners with local hospitals, primary care providers, and universities to conduct influenza surveillance. Annual influenza epidemics follow a winter seasonal pattern in the United States with typical activity peaking during late December to February. Surveillance activities help to monitor and prepare for the impact of influenza on the healthcare system. Moreover, influenza surveillance in California is vitally important to monitor for importation of novel strains of influenza from other parts of the world.
 
Surveillance for influenza activity in Orange County includes monitoring of the following components year-round:

  • Influenza viruses:¬†specimens are submitted to the Orange County Public Health Laboratory from participating hospitals, physicians, and laboratories for tracking and strain-typing.
  • Influenza-like illnesses (or ILI): sentinel providers (physicians, nurse practitioners, physician assistants) report outpatient influenza-like illnesses and submit specimens.
  • Pneumonia and influenza deaths: death certificates are reviewed for deaths from pneumonia or influenza.
  • Severe influenza and deaths (in persons under 65 years of age):¬†cases are reported by health care providers and hospital infection control professionals.
  • Outbreaks of respiratory illness: investigation is conducted and control measures are recommended to prevent further disease transmission.
  • Enhanced surveillance for human cases of avian influenza: health care providers are requested to report any patients with fever and respiratory symptoms who traveled to affected areas in the 7-10 days prior to symptom onset (specific criteria will be distributed as novel strains are identified).

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Resources

Last reviewed January 11, 2019