Flu season arrived early in San Diego County, and fewer than one in 10 residents have gotten a shot.

Test positivity reached 8% in the week ending Saturday, Oct. 3, up from 0.7% in the same week last year, according to the county's Respiratory Virus Surveillance Report. The county typically does not see increased flu activity until mid-November.

For Encinitas-area residents who haven't been vaccinated, the North Coastal Public Health Center and community events coordinated by TrueCare offer shots for uninsured and underinsured residents. The county's Immunization Unit can be reached at (866) 358-2966.

262 hospitalizations, eight deaths

As of Oct. 3, the county had recorded 262 flu hospitalizations and eight deaths for the 2026-27 season. Fifty-eight of those hospitalizations came in the most recent reported week alone. Only 10.2% of county residents had received a flu vaccine.

County Public Health Officer Sayone Thihalolipavan urged residents to act quickly in an Oct. 9 announcement.

"The vaccine looks like it will be highly effective against the strain of flu now circulating," Thihalolipavan said.

Health care providers recommend vaccination by Halloween. The flu vaccine is covered by insurance and available at pharmacies and clinics countywide.

New forecasting tool

The same Oct. 9 announcement introduced a revised weekly respiratory report that now includes two-week hospitalization forecasts for flu, COVID-19 and respiratory syncytial virus (RSV).

The forecasting section was built through a partnership with UC San Diego's Resilient Shield project, a CDC-funded research effort led by Dr. Eliah Aronoff-Spencer, a professor of medicine. The tool follows the CDC's EpiNow 2 protocol, using recent hospitalization trends to project whether admissions will rise, fall or hold steady, the San Diego Union-Tribune reported.

Seema Shah, medical director of County Epidemiology and Immunization Services, compared the tool to a weather forecast for families planning gatherings, the Union-Tribune reported. Color-coded arrows at the top of the report show whether test positivity and emergency visits for each virus are trending up, stable or down.

The Resilient Shield partnership previously built an interactive dashboard tracking the Tijuana River Valley sewage crisis and has helped guide the county's surveillance of the New World Screwworm threat.

West Coast pattern

The early surge is not unique to San Diego. Los Angeles County's flu season started Sept. 28, ahead of its typical early-November start, according to the Los Angeles Times. California had recorded 34 flu-related deaths statewide as of early October.

The county's weekly surveillance report publishes every Thursday through April. The next edition is expected Thursday, Oct. 15.