What is the Flu: 10 Simple Key Facts

The flu is a viral infection that affects the respiratory system. It causes fever, weakness, and can spread very quickly from person to person.

When the first symptoms appear, you can talk to a doctor online. A remote consultation helps assess your condition, decide whether you need an in-person check-up, and get recommendations or antiviral treatment. This reduces the spread of infection and saves time.

The flu spreads mainly through droplets when someone coughs or sneezes. It can also spread through hands or surfaces.

🔟 Ten Key Facts About the Flu

1️⃣ Virus Types

There are three main flu virus types:

• Type A — causes large outbreaks and pandemics.
• Type B — affects only humans, usually causes smaller outbreaks.
• Type C — usually mild or without symptoms.

2️⃣ The Virus Changes Often

The flu virus changes its structure regularly.
This is why the flu vaccine needs to be updated every year.

There are two types of changes:

• Antigenic drift — small gradual changes.
• Antigenic shift — a big sudden change that can lead to a pandemic.

3️⃣ How the Flu Spreads

• Mainly through coughing, sneezing, talking.
• Also through hands and objects.
• The virus dies quickly in heat, sunlight, and with disinfectants.

4️⃣ Incubation Period

• Usually 1–3 days.
• A person is contagious even before symptoms appear and for 5–7 days after.

5️⃣ Symptoms

Flu usually starts suddenly:

• high fever (38–40°C)
• chills
• headache
• muscle and joint pain
• dry cough, sore throat
• weakness and fatigue
• children may have stomach symptoms

6️⃣ Possible Complications

• viral or bacterial pneumonia
• myocarditis (heart inflammation)
• meningitis, encephalitis
• worsening of chronic diseases (asthma, diabetes, heart disease)

7️⃣ Diagnosis

Diagnosis is based on symptoms and laboratory tests, such as:

• PCR tests
• rapid antigen tests
• antibody tests

8️⃣ Treatment

Mostly supportive care:

• fever reducers
• rest and hydration
• oxygen therapy if needed

Antiviral medicines (like oseltamivir/Tamiflu) may be recommended.
Antibiotics are used only for bacterial complications.

9️⃣ Prevention

Annual flu vaccination is recommended for:

• medical workers
• older adults
• pregnant women
• people with chronic diseases

Extra protection:

• hand hygiene
• masks
• avoiding crowded places in flu season

🔟 When Is the Flu Most Active?

Mainly in autumn and winter, when people stay indoors more and humidity is low.

📱 Telemedicine is a safe and convenient way to get help quickly and reduce the spread of flu.