The flu season in California is off to an aggressive start as cases climb earlier than usual and doctors recommend getting vaccinated.<\/p>\n
\u201cIf people are considering getting the flu vaccine<\/a>, and they haven\u2019t yet, they should get it like now,\u201d said Rakesh Chaudhary, physician-in-chief at Kaiser Permanente Santa Clara. \u201cBecause there is so much flu out there.\u201d<\/p>\n Levels of flu strains in wastewater were measured at high levels in Santa Clara County<\/a>, San Francisco and Marin County. Regionally, more than one-fifth of tests for the flu came back positive the last week of October, a \u201cvery high\u201d rate, according to the California Department of Public Health. That rate, 21.3%, is higher than any point during the 2025-2026 flu season, the data show.<\/p>\n For most people, a case of influenza, known as the flu, is similar to the common cold. It poses greater health risks to children under 2 years old and older adults, and can lead to hospitalization. People with compromised immune systems or other conditions, such as asthma and heart disease, are at higher risk too.<\/p>\n In the Bay Area, patients are being admitted to the hospital due to the flu at a rate on par with the peak of last year\u2019s flu season in January 2026.<\/p>\n \u201cOur hospital feels as busy as it does usually in January and February,\u201d he said.<\/p>\n Statewide, 120 deaths have been attributed to influenza so far this season.<\/p>\n Based on guidance from national medical associations, the California Department of Public Health recommends a flu shot for anyone older than 6 months. A chorus of physicians in the Bay Area recommends it every season, as well.<\/p>\n When a flu vaccine is a good match for the strains circulating, it can reduce trips to the doctor\u2019s office by between 40% and 60%, according to research cited by the CDC<\/a>. During the 2024-25 season, vaccination prevented 180,000 influenza-related hospitalizations nationally and 12,000 deaths.<\/p>\n Influenza strains mutate quickly, posing a challenge for scientists who design new vaccines to debut every fall. On the recommendation of the U.S. Food and Drug Administration, vaccine developers updated formulas this year to protect against strains expected to circulate in the Northern Hemisphere this season.<\/p>\n Among the updates, the FDA said the new vaccine is designed to better protect against subclade K, a mutation of an influenza virus that spread quickly last virus season and was described as a \u201csuper bug\u201d by some media outlets.<\/p>\n