What Are the Symptoms of Flu, and How Does It Go Away? An Influenza Guide

Short Answer

Flu is a respiratory infection caused by the influenza virus. According to the Turkish Ministry of Health, symptoms usually last 7 days and are most severe in the first 2–3 days. Most people recover at home with rest and plenty of fluids; antibiotics do not help with flu. If you are over 65, pregnant, have a chronic illness or are under 2 years old, see a doctor within the first 48 hours. If you have shortness of breath, chest pain or confusion, call 112 (the emergency number in Türkiye).

What are the symptoms of flu (influenza)?

According to the Ministry of Health, symptoms appear 1–3 days after the virus enters the body. Flu usually starts suddenly. One or more of the following symptoms occur:

• Fever of 38 °C or higher, chills
• Dry cough and sore throat
• Runny or stuffy nose
• Headache, muscle and joint aches
• Severe fatigue
• Sometimes diarrhea; vomiting and diarrhea are more common in children

In young children, restlessness, loss of appetite and drowsiness are also symptoms to watch for. According to the Ministry, fatigue can last for several weeks after the flu has passed. According to the WHO, the cough can also last 2 weeks or longer.

Flu, common cold or COVID-19?

According to the Ministry of Health's comparison and CDC data, the main differences are:

Feature	Flu	Common cold	COVID-19
Onset	Sudden	Gradual	May start later than flu
Fever	Common, above 38 °C	Rare	May occur
Muscle aches	Common and severe	Mild	May occur
Fatigue	Marked, can last for weeks	Very mild	May occur
Runny nose, sneezing	Sometimes	Common	May occur
Loss of taste and smell	May occur	May occur	More common than in flu
Incubation period	1–4 days	—	2–5 days, up to 14 days

According to the CDC, flu and COVID-19 cannot be told apart by symptoms alone. A test is needed for a definite distinction. Details are in our guide to telling flu and COVID apart.

How contagious is flu?

According to the Ministry of Health, a sick person starts to spread the infection 1 day before symptoms begin. Contagiousness lasts until days 5 to 7 of the illness. According to the CDC, the most contagious period is the first 3 days of the illness.

The virus is mostly spread by droplets released through coughing and sneezing. According to the Ministry, droplets can spread 1–2 meters. On surfaces such as door handles, tables and glasses, the virus stays alive for 2–8 hours.

What helps at home?

The recommendations of the Ministry of Health and the NHS are, in order:

• Stay home and rest: Avoid crowded places so as not to spread the illness to others.
• Drink plenty of fluids: This prevents dehydration. The Ministry also recommends eating fresh vegetables and fruit.
• For fever and pain: Paracetamol or ibuprofen can be used. Do not exceed the dose on the package leaflet.
• Ask first: If you are pregnant, have kidney or liver disease or a stomach ulcer, or take a blood thinner, consult your doctor or pharmacist before taking a painkiller. For children, also ask a doctor or pharmacist first.
• Hygiene: When coughing, use a disposable tissue or the inside of your elbow. Wash your hands often.
• Mask: If you must go to a healthcare facility, wear a mask.

Loss of appetite is common with flu. There is no need to force yourself to eat; prioritize taking in fluids.

Treatment options

Antibiotics: According to the Ministry of Health, antibiotics are of no benefit in treating flu or the common cold. Antibiotics act on bacteria, not viruses.

Antiviral drugs: According to the Ministry, people in risk groups should see a doctor in the first 24–48 hours of the illness and receive antiviral treatment. According to the CDC, these drugs work best when started within 1–2 days after symptoms begin. They can shorten the illness by about a day.

Antivirals are prescription drugs. The Ministry asks that these drugs not be used unless recommended by a doctor. Only your doctor decides which drug to use and for how long.

Who is at risk?

According to the Ministry of Health, flu can be more severe in the following people:

• People aged 65 and over and children under 2
• Pregnant women
• People with metabolic diseases, including diabetes
• People with chronic respiratory diseases, including asthma
• People with chronic kidney, heart and vascular diseases
• People with weakened immunity (such as cancer treatment, immunosuppressive drugs, HIV)
• Those aged 6 months to 18 years who need long-term aspirin
• Residents of nursing homes and care homes
• People with obesity

In these people, complications such as pneumonia, middle ear infection and, rarely, heart muscle damage can develop.

What should you not do?

• Do not give aspirin to children and teenagers: According to the NHS, aspirin is not given to those under 16 unless prescribed by a doctor. Aspirin is associated with a serious liver-brain disorder called Reye's syndrome.
• Do not start antibiotics on your own: Flu is a viral infection, and antibiotics do not act on viruses. The Ministry asks that drugs not be used without a doctor's recommendation.
• Do not use antiviral drugs without a prescription: According to the Ministry, these drugs are used only on a doctor's recommendation.
• Do not go to work or school while sick: The first days are the most contagious period.
• If you are in a risk group, do not wait: According to the Ministry, people in risk groups must see a doctor.

What does the evidence say?

Flu vaccine: According to the Ministry of Health, the vaccine can provide 50–80% protection if it matches the circulating viruses. Protection is lower in older people, but scientific publications have shown that it reduces complications and deaths.

Can the vaccine give you flu? According to the Ministry, the flu vaccine is an inactivated (killed) virus vaccine. Therefore, vaccine-induced flu cannot occur. After vaccination, 15–20% of people may have pain, redness or swelling in the arm.

Antivirals: According to the CDC, an antiviral started early shortens the illness by about a day. Their effects are more pronounced when started early.

Antibiotics: Antibiotics are of no benefit in flu. For more, see our guide to antibiotics and flu.

Folk beliefs: We examined the basis for sayings such as "feed a cold, starve a fever" in a separate guide.

In Türkiye

• Vaccination timing: According to the Ministry of Health, the best period for vaccination is October and November. Those who have not been vaccinated can get the vaccine until the end of March.
• Duration of protection: According to the Ministry, protection begins 2 weeks after vaccination and lasts about 6–8 months. The vaccine should be repeated every year.
• Who should not get it: It is not given to babies under 6 months or to those with a history of serious allergy to the vaccine.
• Pregnancy: The Ministry of Health considers pregnant women a risk group and recommends that they get the flu vaccine. The Ministry's vaccine page does not recommend the vaccine in the first 3 months of pregnancy. According to the CDC, however, the vaccine can be given at any stage of pregnancy. Discuss the timing with your doctor.
• Access to antivirals: According to the Ministry, antiviral drugs prescribed by a doctor are provided free of charge at hospitals, community health centers and family health centers.
• Source of information: The Ministry's grip.saglik.gov.tr website contains information on risk groups and vaccination.

For the vaccine composition for the 2026–27 season, see our guide to the new-season flu vaccine.

Which doctor should you see?

• First step: Your family physician. If you are in a risk group, go within the first 48 hours.
• Children: Family physician or Pediatrics.
• Pregnant women: Family physician or Obstetrics and Gynecology.
• People with chronic illness: Also inform the doctor who follows you.
• Bring with you: The time symptoms began, the temperatures you measured and a list of the medicines you take.

We explain in detail when you need to see a doctor in our guide to seeing a doctor for flu.

When should you seek emergency care?

According to the CDC's emergency warning signs:

• If you have difficulty breathing or shortness of breath, call 112.
• If you have persistent pain or pressure in the chest or abdomen, call 112.
• If there is confusion, difficulty waking up or seizures, call 112.
• If a child has fast breathing, bluish lips or ribs pulling in with each breath, call 112.
• If symptoms improve and then worsen again with fever and cough, go to the emergency department without waiting.
• If you are not passing urine, or have persistent dizziness or severe muscle pain, go to the emergency department without waiting.
• If a child has a fever above 40 °C that does not come down despite medication, or cannot take fluids, go to the emergency department without waiting.
• If a baby under 3 months has a fever of 38 °C or higher, go to the emergency department without waiting.
• If a chronic illness such as asthma, heart failure or diabetes is getting worse with the flu, go to the emergency department without waiting.
• If you are in a risk group and symptoms have just started, see your family physician the same day.

Related guides

• When should you see a doctor for flu?
• How to tell flu and COVID apart
• Can the flu vaccine be given on the same day as other vaccines?
• 2026–27 flu vaccine: who, and when?
• How to get rid of a persistent cough
• When should fever reducers be used?
• All symptom guides

What changed? (October 2026)

• New guide: Flu symptoms, contagiousness, home care and warning signs brought together on one page.
• The Ministry of Health's seasonal flu pages, the WHO's 2025 influenza fact sheet and the CDC's 2026 antiviral information were followed.

Sources

• T.C. Sağlık Bakanlığı, HSGM. Mevsimsel Grip: Grip nedir, belirtileri ve bulaşma. 2024. https://grip.saglik.gov.tr/tr/mevsimsel-grip.html (accessed October 7, 2026)
• T.C. Sağlık Bakanlığı, HSGM. Kimler Risk Altında? 2024. https://grip.saglik.gov.tr/tr/kimler-risk-altinda.html (accessed October 7, 2026)
• T.C. Sağlık Bakanlığı, HSGM. Grip Aşısı. 2024. https://grip.saglik.gov.tr/tr/grip-asisi.html and T.C. Sağlık Bakanlığı. Grip Aşısına İlişkin Açıklama (press release). https://www.saglik.gov.tr/TR-60873/grip-asisina-iliskin-aciklama.html (accessed October 7, 2026)
• T.C. Sağlık Bakanlığı, HSGM. Tedavisi Nedir? and Soğuk Algınlığı comparison. 2024. https://grip.saglik.gov.tr/tr/tedavi.html (accessed October 7, 2026)
• World Health Organization. Influenza (seasonal) fact sheet. February 28, 2025. https://www.who.int/news-room/fact-sheets/detail/influenza-(seasonal) (accessed October 7, 2026)
• CDC. Signs and Symptoms of Flu. Updated August 26, 2024. https://www.cdc.gov/flu/signs-symptoms/index.html (accessed October 7, 2026)
• CDC. Treating Flu with Antiviral Drugs. Updated June 26, 2026. https://www.cdc.gov/flu/treatment/antiviral-drugs.html (accessed October 7, 2026)
• CDC. Similarities and Differences between Flu and COVID-19. Updated September 17, 2024. https://www.cdc.gov/flu/about/flu-vs-covid19.html (accessed October 7, 2026)
• NHS. Flu (reviewed February 3, 2026); Reye's syndrome (reviewed September 14, 2023). https://www.nhs.uk/conditions/flu/ and https://www.nhs.uk/conditions/reyes-syndrome/ (accessed October 7, 2026)
• CDC. Flu Vaccine Safety and Pregnancy. Updated September 17, 2024. https://www.cdc.gov/flu/vaccine-safety/vaccine-pregnant.html (accessed October 7, 2026)