Flu activity in California is running weeks ahead of a typical season, and emergency departments are feeling it first.
Four California health systems told Becker’s what they are seeing so far: more ED visits and positive tests, admissions rising and open questions about whether the early surge will fade or overlap with COVID-19 and respiratory syncytial virus later this winter.
“California has a full-on flu epidemic right now,” Scott Gottlieb, MD, a former FDA commissioner, recently said in an interview with CNBC.
As of the week ending Oct. 3, influenza-like illness accounted for 2.77% of outpatient and emergency department visits in California, compared with 1.85% nationally, according to CDC data. Hawaii and Louisiana have “low” influenza-like illness activity. The rest of the country falls in the CDC’s “minimal” category.
Compared to respiratory virus seasons in 2022-23, 2023-24 and 2024-25, this season is starting sooner.
Kaiser Permanente: December-level positivity in October
At Oakland, Calif.-based Kaiser Permanente, flu positivity rates in mid-October resemble figures typically seen in early December, according to Elizabeth Hudson, DO, regional chief of infectious diseases at Kaiser Permanente Southern California.
“Comparing our current flu positivity rates with prior years at Kaiser Permanente, we are seeing rates that are more like what we usually see in early December,” Dr. Hudson said. “This has been the case for the past two to three weeks, with the upward trajectory continuing at this time.”
Most cases are being diagnosed and treated in urgent care, emergency departments and outpatient settings, including virtual care. Hospitalizations are starting to rise, mostly among older adults, immunocompromised patients and others at higher risk. Dr. Hudson said the system is managing the increase for now. The bigger question is what comes next.
“Will this be an early spike of flu cases that die down over the next six weeks, or will this be a prolonged season that will collide with COVID and RSV spikes that may come later in the season?” she said.
Kaiser has not implemented visitor restrictions. It has told members and staff about the unusually early start to the season and urged them to get vaccinated as soon as possible.
Sharp HealthCare: ICU admissions up 30%
San Diego-based Sharp HealthCare is seeing more flu-related emergency department visits than at this point last year. Inpatient admissions from the emergency department are up 8%, and ICU admissions are up 30%, said Trisha Khaleghi, MSN, RN, senior vice president and CEO of the Sharp Metropolitan Medical Campus and Sharp Mary Birch Network.
The biggest strain is on staffed beds and on patients waiting in the ED for an inpatient bed.
“When admissions rise at the same time team members are out sick, it can create additional pressure across the hospital,” Ms. Khaleghi said. “Delays in discharging patients can also affect how quickly beds become available for those waiting in the emergency department.”
Sharp is adding shifts, bringing in travel nurses, expanding treatment spaces and coordinating patient placement and discharge planning across departments.
Cedars-Sinai: An early start, not yet a severe one
At Los Angeles-based Cedars-Sinai, flu activity began rising in early September, said Jonathan Grein, MD, director of hospital epidemiology and associate professor in Cedars-Sinai’s department of medicine.
“We have experienced an earlier start to the influenza season than usual,” Dr. Grein said. “Influenza activity began increasing in early September, especially in the emergency department. Our inpatient influenza volume is increasing modestly, in line with experience from previous influenza seasons.”
So far, nothing indicates the season will be more severe than usual, according to Dr. Grein.
“We continue to monitor influenza activity and inpatient census closely,” he said. “Contingency plans for increased inpatient bed needs are in place and can be operationalized as needed. Additional measures, such as mandatory masking and visitor restrictions, will be considered based on influenza activity.”
Cedars-Sinai said its mandatory flu vaccination policy has pushed employee vaccination rates above 98%.
John Muir Health: Positivity up, volumes steady
Walnut Creek, Calif.-based John Muir Health has seen more flu testing in its EDs than in the third quarter of 2025. Flu positivity sits at 2.1%, up from 0.5% during the same period last year, a spokesperson said.
“So far, we’re not overwhelmed and we’re not experiencing a huge spike in ED volumes,” the spokesperson said.
Advice for leaders elsewhere
With flu activity still minimal in most of the country, California’s early season offers a preview for other regions. Ms. Khaleghi’s advice: Start before volumes rise.
“Monitor local respiratory illness trends alongside your own operational data, establish clear plans for when and how to expand capacity, and address potential staffing and discharge challenges early,” she said. “When front-line teams understand the plan, their roles and the resources available to them, the entire organization is better positioned to respond while continuing to provide safe, high-quality care.”
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