What are common symptoms of the flu?

Health officials warn that seasonal influenza typically produces a cluster of sudden symptoms that distinguish it from the common cold. Infectious disease specialists say fever—often reaching 100.4°F (38°C) or higher—accompanied by chills, is common, along with cough and sore throat. Patients frequently report nasal congestion or a runny nose, headaches, and muscle or body aches. Extreme fatigue and weakness often begin early and can be severe.

Gastrointestinal symptoms such as nausea, vomiting and diarrhea occur more often in children than adults, clinicians note. Onset is typically abrupt, with symptoms appearing one to four days after exposure. Most patients recover within five to seven days, but cough and tiredness may linger for several weeks.

Medical experts emphasize that certain signs warrant prompt clinical evaluation. Difficulty breathing, chest pain, sudden dizziness, confusion, persistent high fever or a fever that returns after improving, and symptoms that worsen after initial improvement are red flags. Infants, older adults, pregnant people and individuals with chronic medical conditions face higher risk of complications and should seek earlier care.

Prevention measures recommended by public health authorities include annual vaccination, good hand hygiene, respiratory etiquette and staying home when ill. Antiviral medications, when prescribed early—ideally within 48 hours of symptom onset—can reduce severity and duration.

Health systems urge the public to consult a healthcare provider for personalized guidance. Infectious disease specialists affirm that timely recognition of common influenza symptoms, combined with prevention and early treatment, reduces complications and transmission.

Rapid diagnostic tests and laboratory assays can confirm influenza; clinicians weigh test results, symptom timing and patient risk to guide therapy. A high fever above 103°F (39.4°C), persistent vomiting, signs of dehydration or inability to perform daily activities signal the need for immediate medical attention. Vaccination remains the primary preventive tool, updated annually to match circulating strains. Seek timely care.