Influenza, or the flu, is a highly contagious respiratory infection that is caused by the influenza virus. According to the Centers for Disease Control and Prevention (CDC), an uncomplicated influenza infection will last from three to seven days in most people, including children, although a cough and feelings of weakness or fatigue can last for two weeks or longer.

Some people are at an increased risk of developing flu-related complications, which can include:

Flu-related complications can lead to hospitalization and even death.

Additionally, flu infection may make preexisting conditions worse. For example, if you have asthma, you may experience more severe asthma attacks while you have the flu.

You are at increased risk of developing flu-related complications if you:

  • are aged 65 and older
  • are younger than 5 years old and particularly younger than 2 years old
  • are pregnant or two weeks postpartum
  • are extremely obese (BMI of 40 or more)
  • live in a nursing home or long-term care facility
  • have a weakened immune system, such as people with cancer or HIV
  • have a chronic illness, such as asthma, diabetes, or chronic obstructive pulmonary disease
  • have a liver or kidney disorder

Do some strains of the flu last longer than other strains?

Although different influenza subtypes don’t generally affect the duration of illness, some subtypes can cause more severe illness than others.

According to the CDC, influenza A (H3N2) viruses are associated with more hospitalizations and deaths in children and the elderly than other human influenza subtypes, such as influenza A (H1N1) and influenza B. Additionally, vaccine effectiveness for A (H3N2) viruses is generally lower.

Flu vs. cold duration

Despite having some overlapping symptoms, colds and the flu are two separate illnesses. Colds are typically milder than the flu. Cold symptoms will typically resolve in about 7 to 10 days. Learn more about the differences between a cold and the flu.

It may take one to four days after exposure to the influenza virus for symptoms to develop.

If you have the flu, you’ll be contagious one day prior to developing symptoms and up to five to seven days after becoming ill. Younger children or people with a weakened immune system may be contagious for longer.

The influenza virus can also survive on surfaces, such as doorknobs and tables, for up to 24 hours. Viruses live longer on materials such as stainless steel, plastic, and other hard surfaces. To avoid spreading the virus, it’s always important to wash your hands frequently and avoid touching your face or mouth.

If you have the flu, your doctor may prescribe an antiviral medication, such as oseltamivir (Tamiflu). Antiviral medications may reduce the length of your illness or help prevent complications. Additionally, receiving the flu vaccine can also shorten the duration of your illness.

There isn’t current scientific evidence supporting the effectiveness of natural products or home remedies against the flu.

If you are sick, be sure to drink plenty of liquids and get plenty of rest. You can also take over-the-counter pain relievers such as ibuprofen or acetaminophen to help relieve your symptoms. It’s recommended that you stay at home while you’re ill, and for at least 24 hours after your fever has gone down.

Most flu symptoms will typically resolve within a week. However, the flu can cause serious complications in at-risk groups or in people with preexisting conditions. If you or your child experience any of the following symptoms, you should seek medical attention immediately:


  • trouble breathing or feeling short of breath
  • pressure or pain in your chest or abdomen
  • dizziness that comes on suddenly
  • confusion
  • vomiting
  • symptoms that seem to improve, but then return or worsen

Children and infants

  • trouble breathing or breathing quickly
  • not getting enough fluids
  • not being able to eat
  • not waking up
  • not interacting or not wanting to be held
  • skin that is blue in color
  • fever that comes with a rash
  • fewer wet diapers than usual
  • symptoms that seem to improve, but then return or worsen

If you come down with the flu, your symptoms will typically resolve on their own within a week. Prescribed antiviral medication may reduce this duration.

But if you have a high risk of complications or start to experience the more severe symptoms outlined above, contact your doctor right away.