Influenza is an airborne viral respiratory condition characterized by symptoms of fever, cough, sore throat, and myalgia. Illness can be mild to severe. Persons with a compromised immune system or a chronic respiratory condition may be at increased risk for complications such as respiratory distress, pneumonia, or death.

The best way to prevent influenza is by getting an influenza vaccination each year, washing hands frequently, and avoiding close contact with ill persons. Seasonal influenza vaccines include the strains of influenza A and influenza B considered most likely to circulate that season.

The San Diego County Epidemiology Program (EPI), Immunization Program (IZ), and the Public Health Laboratory (PHL), conduct year-round influenza surveillance with the assistance of medical providers and partners throughout San Diego County. 

The sections below provide information on the current influenza season, influenza vaccine, reporting of influenza cases and outbreaks, laboratory testing at the Public Health Laboratory, prevention and control of influenza, and other educational resources and materials.


Migrant Shelter Influenza Outbreak


Influenza Surveillance

Click the links below for current information

Influenza Vaccination Information
Influenza Reporting

Updated guidance regarding reporting, infection control, and outbreak definitions for schools is being revised and will be posted here when available.

Physicians and laboratories are encouraged to report any laboratory-confirmed influenza (including rapid tests) to the San Diego County Epidemiology Program by faxing the laboratory results and/or a Case Report Form or CMR to Fax (858) 715-6458

Influenza is reportable to the San Diego County Epidemiology Program in the following circumstances:

SD County Requests Reporting of: State Law Requires Reporting of:

All laboratory confirmed influenza

Novel influenza virus strains (human)

Influenza-related ICU and/or death, all ages 

Deaths 0-17 years of age

 Influenza outbreaks

Influenza outbreaks

The Public Health Laboratory (PHL) requests specimens from laboratory-confirmed influenza cases that have expired or required care in the ICU for severe influenza to be submitted for PCR confirmation and subtyping. Contact PHL for more information at (619) 692-8500. The San Diego Public Health Laboratory Test Requisition Form must be used to submit influenza specimens to PHL.

Influenza Outbreaks

Influenza outbreaks should be promptly reported by telephone to the Epidemiology Program at (619) 692-8499, or (858) 565-5255 after hours, in the following circumstances:

Outbreaks in institutions and other residential facilities (e.g., long term care facilities, homes for the developmentally disabled or chronically ill, sleepover camps, prisons) with at least one case of laboratory confirmed influenza in the setting of a cluster (≥2 cases) of influenza-like illness (ILI) within a 72-hour period.

Influenza-like illness (ILI) is defined as fever (≥100° F or 37.8° C) and a cough and/or a sore throat, in the absence of a known cause other than influenza.

Outbreaks of acute respiratory illness in institutions or other congregate settings (e.g., schools, day camps) associated with hospitalizations or fatalities above baseline for that institution or setting.

Outbreaks of acute respiratory illness in an institution, congregate setting, or community where at least one case has had recent exposure to swine, recent travel to an area where novel influenza is circulating, or contact with a confirmed case of swine or novel influenza.

Prevention and Control of Influenza Outbreaks in Long-Term Care Facilities

The following guidance documents and resources are available to assist with preventing, managing, and controlling influenza outbreaks in long-term care facilities and similar settings.

Educational Materials and Resources

Additional Resources

For more information, contact the Epidemiology Program (619) 692-8499 or send us an e-mail.