If you get the flu, how long should you expect it to last? If you’re under the age of 65 and generally healthy, you can probably expect the worst of your flu symptoms — which can include fever or chills, cough, sore throat, a runny or stuffy nose, body aches, headaches, and heavy fatigue — to last between three to seven days. For adults who got their flu shot, it’ll likely take closer to three days for symptoms to start easing up; for unvaccinated people, it will probably take longer.
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Source: Centers for Disease Control and Prevention

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