Flu (influenza): Symptoms and treatment

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Flu symptoms

COVID-19 and the flu can have similar symptoms. If you start to develop any of the symptoms below, follow the same precautions taken for COVID-19.

Flu symptoms may vary from person to person. Some people only get mildly ill. Others get very sick.

Flu symptoms appear 1 to 4 days after exposure to the virus. Usually they include the sudden appearance of:

  • fever
  • cough
  • muscle aches and pain

Other common symptoms may include:

  • headache
  • chills
  • fatigue (tiredness)
  • loss of appetite
  • sore throat
  • runny or stuffy nose

Some people (especially children) may also have:

  • diarrhea
  • nausea and vomiting

Additional symptoms to watch for in children

As a parent, you know your child best. Talk to your health care provider right away if you notice any of these symptoms:

  • not drinking or eating as usual
  • not waking up or interacting with others
  • irritable (not wanting to play or be held)

Contagious period

People infected with the flu virus can spread it to others:

  • starting 1 day before the first symptoms
  • until approximately 5 days after the first symptoms

Similarities between the symptoms of the flu and COVID-19

The flu and COVID-19 are different viruses. They are very contagious and have similar symptoms. This can make it hard to tell the difference between the flu and COVID-19 when symptoms appear.

If you start to develop symptoms, follow the same precautions taken for COVID-19.

While there is no vaccine yet for COVID-19, we do have vaccines against the flu. This year, more than ever, it is important for everyone 6 months and older to get the flu shot. This will help prevent the flu and flu-related complications. Preventing the flu will also help reduce stress on the health care system during the COVID-19 pandemic.

If you get the flu

If you do get sick, stay home to help prevent the spread of the flu or potentially COVID-19. Avoid close contact with other people until you feel well enough to get back to your usual day-to-day activities. This is especially important for people who have higher chances of developing complications from the flu.

Whether you have flu or COVID-19 can only be confirmed with a test. Because of this, you should also follow COVID-19 prevention measures to help keep others safe.

Most people recover from the flu in 7 to 10 days.

If you are a person at high risk of flu or COVID-related complications and develop symptoms, contact your health care provider. Tell them about your symptoms over the phone before your appointment and follow their instructions. That way, they can arrange to see you without exposing other people.

If you need immediate medical attention, call 911 and tell them your symptoms.

Possible complications of the flu

  • pneumonia and respiratory failure
  • worsening of chronic health conditions

Other severe outcomes of the flu

  • hospitalization
  • death

How the flu is diagnosed

The flu is usually diagnosed by your health care provider based on:

  • symptoms
  • laboratory tests (nose or throat swab)

Flu treatment

Flu symptoms can be treated with:

  • rest
  • fluids, like water
  • medication to reduce any fever or aches

In some cases your health care provider may prescribe medication, especially if you are:

  • at high risk for flu-related complications
  • very sick with severe symptoms

Over-the-counter cough and flu medicine should not be given to children younger than 6 years old. It is only safe to do so if you are advised to by your health care provider.

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