How Long Do the Symptoms of the Flu Last?

Published June 30th, 2022 by Chris Riley
Fact Checked by
Jacqueline Hensler
Medically Reviewed:
Erik Rivera

What is the flu | Symptoms | Treatments | Prevention

The flu, also called influenza, is a highly contagious virus that can cause fever, body aches, congestion, and other symptoms.

Your symptoms of the flu can last for a week or more and it may be difficult to tell when you are no longer contagious.

The virus can be deadly, especially if you are elderly or have a preexisting condition, and treatment options can vary depending on the severity of symptoms.

In this article, we will answer how long flu symptoms last while also providing information on how to treat the flu and how to prevent it from spreading.

What is the flu?

The flu is a virus that can cause severe respiratory illness which can affect your throat, nose, and lungs.

It is spread person to person through the air when you cough and sneeze while infected, or by contact with contaminated surfaces and then touching your mouth, nose, or eyes.

There are three different types of flu viruses that infect humans: influenza A, B, and C. Influenza A is the most common and can cause pandemics. Influenza B usually only causes epidemics, while influenza C is not as severe and does not cause widespread outbreaks.

Each of these types of flu viruses also have different flu strains that can change each year due to mutations.

A new flu vaccine, also called a flu shot, is created every year to protect against the most common strains of the virus that are expected to circulate that upcoming flu season.

It is most common to get the flu during flu season which lasts in the U.S. from October through May while usually peaking from December to February.

Complications due to the flu include sinus infection, ear infection, bacterial pneumonia, sepsis, and can make any chronic medical conditions worse.

What are the symptoms of the flu?

Symptoms of the flu normally start one to four days after infection, which is called the incubation period.

There is a rapid onset of symptoms that come on suddenly and they are similar to the common cold but usually involve more severe illness.

Common symptoms of influenza include:

  • Fever which can also cause chills
  • Sore throat
  • Headache
  • Extreme tiredness or fatigue
  • Dry cough
  • Congestion
  • Runny nose or stuffy nose
  • Body aches or muscle pain
  • Nausea
  • Vomiting
  • Diarrhea

Nausea, vomiting, and diarrhea are more common in children although they can occur in adults too.

If you experience these symptoms, it is best to stay home and rest as well as drink plenty of fluids. You need to see your doctor if the symptoms become severe.

flu symptoms image

How long does the flu last?

The flu normally lasts anywhere from three days to about a week.

However, you may experience symptoms for longer if you are a young child, older adult, pregnant woman, or a person with a weakened immune system.

The fever usually lasts anywhere from one to four days after symptoms start while cough and fatigue can last up to two to three weeks.

It is important to note that you are contagious a day before the symptoms start and are still contagious for up to seven days after your initial symptoms.

You are most contagious during the first three to four days due to the fact that this is when you are most sick and likely to cough or sneeze which spreads the virus.

To tell if you are no longer contagious, you need to have no fever for at least 24 hours without the use of fever-reducing medication.

What are the treatment options for the flu?

There is no specific cure for the flu and most healthy people will recover on their own without any treatment.

If your symptoms are not severe the best way to recover from the flu is to get plenty of rest, take an over-the-counter medication such as ibuprofen (Advil, Motrin) or acetaminophen (Tylenol) if you have a fever, and drink lots of fluids to stay hydrated.

There are also four antiviral drugs approved by the Centers for Disease Control and Prevention (CDC) that can be used to treat the flu although these are generally not needed unless you are at a higher risk of complications from the flu, in which case, you can get a prescription from your doctor or health care provider.

The four antiviral flu medications include:

  • Oseltamivir phosphate (Tamiflu)
  • Zanamivir (Relenza)
  • Peramivir (Rapivab)
  • Baloxavir marboxil (Xofluza)

Only oseltamivir phosphate is available in a generic form.

These antiviral medicines work best if they are started within the first 48 hours of symptom onset.

Antiviral drugs can help to reduce the severity and duration of your symptoms as well as prevent serious complications from the flu. The most common side effects of these drugs are nausea and vomiting.

If you experience these side effects, it is important to drink plenty of fluids and eat small meals throughout the day.

When do I need to see a doctor?

You will most likely not need to see your doctor if you are a healthy adult and have the flu but there are some circumstances where it may be necessary.

You need to seek medical attention if you have the flu and you are:

  • Younger than two years old
  • Older than 65 years old
  • Pregnant
  • Have a weakened immune system
  • Have a chronic health condition such as heart disease, diabetes, or asthma

You also need to see your doctor if you are experiencing any of the following symptoms:

  • Shortness of breath or difficulty breathing
  • Severe or persistent vomiting
  • Flu-like symptoms that improve but then return with fever and worse cough

You may also consult with your doctor if you have any questions regarding prescribed antiviral medications.

What are the best ways to prevent the flu?

The best way to prevent the flu is to get vaccinated every year.

The CDC recommends that everyone six months of age and older need to get the annual flu vaccine.

There are two types of vaccines available: the flu shot which is given with a needle, and the nasal spray vaccine which is given as a mist into your nose.

The flu vaccine takes about two weeks to become effective so it is best to get vaccinated as soon as the vaccine becomes available in your area which is typically somewhere between August and October.

You can also help to prevent the flu by taking some simple everyday precautions such as:

  • Washing your hands often with soap and water for at least 20 seconds, or use an alcohol-based hand sanitizer if soap and water are not available
  • Avoiding close contact with sick people
  • Staying home from work, school, or other public places if you are feeling sick
  • Covering your mouth with your elbow, sleeve, or tissue instead of your hands when you cough or sneeze
  • Avoiding touching your eyes, nose, and mouth as much as possible
  • Cleaning and disinfecting surfaces that are often touched such as door handles, countertops, light switches, remote controls, etc.

The flu vaccine is effective for several months to a year which is one of the reasons why you need to get it annually.

Summary

The influenza virus is a contagious respiratory illness caused by influenza viruses that infect the nose, throat, and lungs and is different from the common cold because it usually causes more severe symptoms.

Symptoms of the flu include fever, headache, sore throat, muscle aches, fatigue, and cough among several others.

The flu typically lasts for about a week but some of the symptoms can last for up to two weeks.

The best way to prevent the flu is by getting vaccinated every year and following the list above to help prevent it.

There are also antiviral drugs that can help to reduce the severity and duration of your symptoms if you are at risk for complications from the flu or if you have severe symptoms.

If you have any more questions about the flu or how long the symptoms last, please consult with your doctor or health care provider.

References, Studies and sources:

GoodRX Health 

Harvard Health Publishing

WebMD

CDC