The 2026-2027 flu season arrived earlier than usual, with health officials urging Americans to get vaccinated as cases surge in regions like California and Utah. Officials warn that the season’s early start, driven by a more immune-evasive variant, could signal a severe year, though vaccination remains the best defense.
Flu activity in the U.S. has spiked ahead of its typical November onset, with health departments in California, Washington, and Utah reporting a sharp rise in cases. In Los Angeles County, flu activity began in September, weeks earlier than usual, while Utah health officials noted cases mirroring November 2025 levels by early October. We are having the number of cases now that we had starting in November last year,
said Dr. Tamara Sheffield of Intermountain Medical Center, emphasizing the need for immediate vaccination. As respiratory virus season gets underway, Contra Costa Health recommends staying up to date on vaccines,
said Brittany Goldman from the department’s Community & Media Relations division.
Early Start Linked to Immune-Evasive Variant
Health officials attribute the early surge to a new influenza variant with mutations that evade immunity. Dr. Adalja, an infectious disease expert, noted that the G155E mutation in H1N1 strains may explain the early spike. Lab data show people’s antibodies don’t neutralize it as well, especially those born after the 2009 pandemic,
he said. The CDC reported that 96% of U.S. flu cases in late September 2026 were H1N1, with only 4% being H3N2, a shift from the previous year’s dominant strain. Flu levels are increasing with the possibility of an early flu season, so now is the time for those eligible to get vaccinated,
said Dr. Jamie Lopez Bernal, Consultant Epidemiologist at the UK Health Security Agency.
Dr. William Schaffner of Vanderbilt University, who has studied the 2026 season, called the early start “unusual.” It started a good month and a half earlier,
he said, adding that cases initially emerged in the West before spreading. This contrasts with the typical Southern U.S. onset, raising concerns about a potentially severe season. In Spokane, Washington, Mark Springer, the communicable disease program manager at Spokane Regional Health District, noted that a typical flu season starts in December, peaks in January, and tapers off in late February to early March.
Vaccination Recommendations Expand
Health departments and medical experts are urging vaccination for all age groups, highlighting updated flu shots and new options. The CDC recommends annual flu vaccines for everyone 6 months and older, with higher-dose and nasal spray options available for specific demographics. The key thing to protect yourself is vaccines,
said Dr. Sheffield, noting that anyone who is age 6 months and older can get an influenza vaccine.
California’s Department of Public Health (CDPH) emphasized that flu vaccines are available through pharmacies, clinics, and providers.
Simple steps, such as getting vaccinated and testing when symptoms appear, keep our community healthy,
said Dr. Sharon Wang, San Bernardino County health officer. Under California law (Assembly Bill 144), health insurance plans are required to cover immunizations recommended by CDPH.
For those hesitant about shots, nasal spray vaccines like FluMist are available for ages 2-49. Older adults can opt for higher-dose formulations, while pregnant individuals are advised to receive the vaccine between 32-36 weeks’ gestation. Vaccines have long been one of the most powerful tools in public health,
said Kate O’Brien of the WHO, countering misinformation about vaccine safety. The updated 2026-27 flu vaccine includes three components tailored to circulating strains, with mFLUSIVA, an mRNA-based vaccine, approved for adults 50 and older.
The American Academy of Pediatrics, American College of Obstetricians and Gynecologists, and other groups recommend flu vaccines for children and adults. You can get flu vaccines at the same time as COVID-19, RSV, or other vaccines,
officials said. Flu vaccines administered during pregnancy offer protection to both pregnant individuals and their infants against preterm birth, low birth weight, and stillbirth. Getting vaccinated helps protect infants, young children, and older adults in your family,
said SOURCE 4.
Historical Context and Concerns
While the 2026 season’s early onset is alarming, experts caution against overestimating its severity. An early start tells you little about when the season will end or how bad it will be,
said Dr. Schaffner. However, the 2009 H1N1 pandemic, which caused global hospitalizations and deaths, serves as a stark reminder of the flu’s potential impact. The flu can be deadly,
warned Dr. Sheffield, noting that complications like pneumonia can be life-threatening, especially for children and the elderly.
Historical data shows that vaccination significantly reduces flu-related hospitalizations and deaths. During the 2024-25 season, the flu vaccine prevented 10 million illnesses and 12,000 deaths in the U.S., according to the CDC. Yet vaccination rates have declined in recent years, with childhood coverage dropping 13 percentage points from 2019-2020 to 2024-2025. Flu vaccination among adults dropped 3% in 2024-2025 compared to the previous season,
said SOURCE 3.
Health officials stress that vaccination is especially critical for high-risk groups, including those with chronic conditions, pregnant individuals, and older adults. These groups are at greater risk of serious complications from influenza,
said Dr. Elizabeth Hudson of Kaiser Permanente Southern California. Many people who are at higher risk of severe flu are also at higher risk of severe Covid-19, and the virus causing Covid-19 continues to circulate.
The CDC designated the 2025-2026 flu season as moderately severe, with over 32 million cases, 390,000 hospitalizations, and up to 81,000 deaths.
Despite the urgency, some remain unconvinced. Many people are not vaccinated yet at this time every year,
said Dr. Russo, though he noted that low vaccination rates alone are unlikely to explain the early season. If we have variants that can evade immunity, that could be a contributor,
he added. SOURCE 6 noted that the 2026-27 flu season’s vaccine was updated to better match expected strains, with all three components revised.
As the season progresses, health departments are monitoring trends closely. San Bernardino County’s dashboard tracks flu-like illnesses, combining data on cases, hospitalizations, and deaths. Together, we can reduce the impact of respiratory viruses in our communities,
said Dr. Wang, urging residents to act now. Simple steps, such as getting vaccinated and testing when symptoms appear, keep our community healthy.
Contra Costa Health Services recommends flu shots as respiratory virus season begins on Nov. 1 and continues through April 30.