Influenza B



Influenza — commonly known as the flu — is a respiratory infection caused by flu viruses. There are three main types of influenza: A, B, and C. Types A and B are similar, but influenza B can only pass from human to human.

The Centers for Disease Control and PreventionTrusted Source reports both types A and B can be equally severe, challenging a previous misconception that type B tends to be a milder disease.

A common indicator of the influenza virus is a fever, often more than 100ºF (37.8ºC). It is highly contagious and in more serious cases can cause life-threatening complications. Learn other symptoms that could indicate a type B influenza infection.

Influenza types

There are three main types of influenza:

  • Type A. The most common form of influenza, type A can spread from animals to humans and is known to cause pandemics.
  • Type B. Similar to type A, influenza B is also highly contagious and can have dangerous effects on your health in more severe cases. However, this form can only be spread from human to human. Type B influenza can cause seasonal outbreaks and can be transferred throughout the year.
  • Type C. This type is the mildest version of the flu. If infected with type C influenza, your symptoms will not be as damaging.

Influenza B symptoms

Early detection of an influenza infection can prevent the virus from worsening and help you find the best course of treatment. Common symptoms of type B influenza include:

Respiratory symptoms

Similar to a common cold, influenza B can cause you to experience respiratory symptoms. Onset symptoms may include:

Body symptoms

A common signal of the flu is a fever that could reach as high as 106ºF (41.1ºC). If your fever does not subside within a few days, seek immediate medical attention.

In addition, you may also experience symptoms including:

Stomach symptoms

In rare cases, the flu may cause diarrhea or stomach pains. These symptoms are more common in children. It can be mistaken for a stomach bug since children infected with type B influenza may experience:

  • nausea
  • vomiting
  • abdominal pain
  • loss of appetite


Media Contact:

Allison Grey
Journal Manager
Journal of Infectious Diseases and Diagnosis