Seasonal Flu: Symptoms, Complications, and Prevention
Every year, the flu affects millions of people worldwide
Dr. Sophie Martin
Infectiologist
In simple terms
Sudden fever, body aches, intense fatigue: seasonal flu is not a simple cold. Discover how to protect yourself effectively.
What is the flu?
The flu is an acute respiratory infection caused by influenza viruses. Unlike the common cold, it comes on suddenly with a high fever (often above 39°C), intense muscle pain, and profound fatigue. According to health authorities, seasonal epidemics cause between 3 and 5 million severe cases each year worldwide.
Characteristic symptoms
Symptoms generally appear 1 to 4 days after exposure to the virus: sudden high fever, chills, headache, joint and muscle pain, dry cough, sore throat, runny nose, and extreme fatigue. In children, vomiting and diarrhea may also occur.
Possible complications
Pneumonia is the most common and feared complication. People over 65, pregnant women, infants, and people with chronic illnesses are most at risk. A bacterial superinfection, myocarditis, or decompensation of an existing illness can occur.
Prevention and vaccination
Annual vaccination remains the most effective way to protect oneself. Guidelines recommend vaccination from 6 months of age. Barrier gestures — hand washing, mask wearing, ventilating rooms — complement protection. In case of symptoms, an antiviral treatment (oseltamivir) can be prescribed within the first 48 hours.
The words explained
Medical terms used above, in everyday language.
- Chronic
- A problem that lasts a long time, usually more than three months, and often comes back.
- Acute
- Something that starts suddenly and lasts a short time.
- Symptom
- A sign you can feel or see that something is wrong, like pain, tiredness or a rash.
- Prevention
- Steps taken before a problem starts, to make it less likely.
- Vaccine
- A safe training session for your immune system, so it can fight a germ later.
When should you see a doctor?
- Your symptoms last more than a few weeks or keep coming back.
- They get worse quickly, or stop you doing everyday things.
- You notice sudden pain, breathing trouble, fainting or bleeding — seek urgent care.
- You already take medication and want to change anything about it.
This article explains general health information. It does not replace advice from your own doctor.
Frequently asked questions
- What is Seasonal Flu: Symptoms, Complications, and Prevention?
- Sudden fever, body aches, intense fatigue: seasonal flu is not a simple cold. Discover how to protect yourself effectively.
- What are the main symptoms or signs of Seasonal Flu: Symptoms, Complications, and Prevention?
- Common signs vary from person to person. The article above lists the symptoms to watch for, how they progress, and when they need medical attention.
- When should you see a doctor for Seasonal Flu: Symptoms, Complications, and Prevention?
- See a doctor if symptoms last more than a few weeks, get worse quickly, stop you doing everyday things, or if you notice sudden pain, breathing trouble, fainting or bleeding.
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