What Exactly Is a Flu-Like Illness?

A flu-like illness is a term health care providers use to describe any virus that causes flu-like symptoms. The real "flu" is only caused by the influenza virus. It can be caused by influenza A or B. However, there are many, many illnesses that cause symptoms similar to those of the flu.

Flu symptoms include:

  • Fever
  • Cough
  • Headache
  • Body Aches
  • Fatigue
  • Congestion

If you have any of these symptoms, but your flu test is negative and your health care provider does not believe you have influenza, she may diagnose you with a "flu-like illness."


When you are diagnosed with influenza, your doctor may be able to prescribe antiviral medications to help shorten the duration and reduce the severity of your symptoms. Unfortunately, these antiviral medications are ineffective against flu-like illnesses that are not caused by the influenza virus.

Instead, treating a flu-like illness will most likely be similar to treating other viral infections. You can treat the symptoms with over-the-counter medications and wait for the virus to run its course.


There are no vaccines or medications that can prevent general flu-like illnesses. Although getting a flu vaccine will help you avoid influenza, you can still get other flu-like illnesses. Instead, taking other measures to stay healthy may help you avoid flu-like illnesses:

  • Washing your hands frequently, and properly, is the most effective way to prevent the spread of germs.
  • When you don't have access to soap and water, hand sanitizer is just as effective at cleaning your hands as long as they aren't visibly soiled. Make sure you always have some with you.
  • If you have a cough, make sure you cover your mouth to reduce the number of germs you are spreading to other people. Just don't cover your mouth with your hands.
  • Sick coworkers leave their germs all around the office and the last thing you want to do is bring them home with you. See what you need to do to stay healthy while you are at work.
  • Getting out of town may seem like a good way to get away from all of the sick people around you, but there will likely be other sick people wherever you are going, or at least on your way there. So be prepared for the germs so you don't end up bringing an illness home as a souvenir.
  • Schools are basically breeding grounds for germs. Lots of kids in tight spaces make for a lot of sick children. See what steps you can take to help minimize your child's chances of getting sick every other week.

A Word From Verywell

Many people get sick with flu-like illnesses every year and mistakenly "diagnose" themselves with the flu. Often, these people will then go on to assume that flu vaccines don't work because they still got the flu when in reality they don't have the flu at all, only a "flu-like illness". While it may seem silly to try to differentiate between the two since they can have very similar symptoms, it is important to understand the differences.

There are many viruses out there that can make us sick and even cause flu-like symptoms. If you have concerns that you may have the flu, contact your healthcare provider. If she diagnoses you with a flu-like illness rather than influenza, now you know a little more about what that means.

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