The CDC recommends annual flu vaccination for all adults. Influenza viruses mutate each year, requiring a new formulation — last year's vaccine does not protect against this year's strains.
The CDC recommends annual influenza vaccination for all adults, ideally before the end of October each year. Influenza viruses mutate constantly, requiring vaccine manufacturers to reformulate each year based on which strains are predicted to circulate. Last year's flu shot does not protect against this year's strains. Influenza causes 9–41 million illnesses and 12,000–52,000 deaths per year in the US, with the highest mortality in adults 65+ and those with chronic conditions. Vaccination typically reduces risk of flu illness by 40–60% when the vaccine matches circulating strains.
Get vaccinated every fall, ideally by the end of October. Vaccination after October is still beneficial — flu season peaks between December and February. If you get flu despite vaccination, the vaccine still reduces the severity of illness and likelihood of hospitalization.
Getting your flu shot and COVID-19 booster in the same visit saves time and is medically fine. Most pharmacies can administer both at the same appointment. You can also request the high-dose flu vaccine (Fluzone HD or FLUAD) if you're 65 or older — these produce a stronger immune response in older adults and are more effective.
Yes — annual flu vaccination is required because influenza viruses mutate each year, and the vaccine is reformulated annually to match the predicted circulating strains. Immunity from last year's vaccine is not effective against this year's strains. Additionally, immunity from the flu shot wanes over approximately 6 months.
No. Standard flu shots contain inactivated (killed) viruses and cannot cause flu illness. The intranasal FluMist contains live attenuated (weakened) viruses but is not recommended for most adults. Mild arm soreness, low-grade fever, and fatigue for 1–2 days after vaccination are normal immune responses to the vaccine, not flu symptoms.
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