Whether the coming flu season is mild or severe could depend less on the virus itself than on how many people get vaccinated.
“As we get further away from the COVID-19 pandemic, we’ve seen an increase in vaccine hesitancy, and this flu season could be much worse if too few people get vaccinated,” said Michael Ben-Aderet, MD, medical director of Hospital Epidemiology at Huntington Health, a Cedars-Sinai affiliate, and associate director of Hospital Epidemiology at Cedars-Sinai Medical Center.
Vaccination rates have fallen since the height of the pandemic. An estimated 52% of people in the U.S. received a flu shot in 2021, compared with less than 44% during the 2025-2026 flu season, according to the Centers for Disease Control and Prevention. Meanwhile, the flu continues to take a serious toll, killing about 45,000 people in the U.S. during the 2024-2025 flu season and sending 710,000 people to the hospital.
“The flu shot remains the most powerful tool available to help prevent serious illness caused by the influenza virus,” Ben-Aderet said. “I urge everyone eligible to receive the vaccine to get it.”
The Cedars-Sinai Newsroom spoke with Ben-Aderet about what to expect this flu season, when to get the flu shot, how to recognize flu symptoms, how to treat it and what the newly approved mRNA flu vaccine means for the public.
When is the Best Time to Get the Flu Shot?
September and October are a good time to get vaccinated, before flu activity typically picks up in November or December. It takes about two weeks for the body to develop an immune response to the vaccine.
The vaccine is recommended for eligible adults and children older than 6 months, according to physician organizations like the American Medical Association. When available, a high-dose flu vaccine is best for those 65 and older because immune response to vaccines can decline with age.
Will the New mRNA Flu Vaccine be Available this Year?
The U.S. Food and Drug Administration approved the first mRNA flu shot in early August. Vaccines made with this technology can be developed more quickly, which could allow for a better match to circulating strains of the virus if they change during a season. However, it is not yet clear when the vaccine will be available or which patients will be eligible. Regardless, it’s great to have another tool to fight the flu.
What are Symptoms of the Flu?
Flu symptoms can include nasal congestion, fever, body aches, cough, sore throat, fatigue and headaches. Vomiting and diarrhea tend to be more common in children. People with the flu can be contagious a day before symptoms start and as long as five to seven days after becoming ill. It’s best to stay home and avoid spreading the virus during that time, and until any fever has resolved.
What Flu Treatment Options are Available?
A mild illness can be treated at home with fluids, rest and Tylenol. Those who are very sick or at higher risk for a serious illness – including older adults, people with weakened immune systems and those with chronic health conditions – should speak with their physician at the first sign of illness to determine whether an antiviral medication like Tamiflu would be right for them. Antivirals should be started within two days after symptom onset to be most effective.
Children with mild illness also will improve at home with supportive care. Parents should watch for worsening symptoms and monitor children 2 and younger to make sure they eat and drink enough. Avoid aspirin when treating a viral illness like the flu in children. Aspirin has been linked to Reyes syndrome, a rare but dangerous condition that causes brain swelling and liver damage and most often appears in children. As with adults, higher-risk children might need an antiviral treatment prescribed by a physician soon after symptoms develop.
When is it Time to See a Doctor in Person or Through a Virtual Appointment?
For those with a mild illness, a virtual visit through a mobile app like Cedars-Sinai Connect is a convenient way to get guidance on the treatment options. Cedars-Sinai Connect providers can order a flu test to rule out other illnesses, like COVID-19 or to prescribe Tamiflu. Over-the-counter flu tests also are available at most pharmacies.
People with more severe symptoms should see their physician in person or visit urgent care. Those symptoms include a very high fever, loss of appetite, trouble breathing or an inability to keep fluids down, as well as symptoms that are not improving. The same applies to people with underlying health conditions.
Beginning Sept. 9, Cedars-Sinai primary care physicians and pediatricians are offering flu shots to patients during scheduled visits including their Tarzana location.