Recognizing and Treating Symptoms of Type B Influenza

Type B flu isn't always more mild than type A. Here's what you should know.

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Influenza, more commonly known as the flu, is a viral illness that affects millions of people every year. There are four types of flu viruses, but the two that cause illness in humans most commonly are influenza A and influenza B. Both cause the same flu symptoms including a runny nose, coughing, fever, and body aches.

This article will outline flu B symptoms and the difference from other flu strains. It will also answer common questions including what causes the flu and flu symptoms duration. 

Man with cold or flu takes his temperature

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Symptoms of Influenza B

Flu B symptoms are often said to be milder than symptoms caused by influenza A. However, flu B can be just as dangerous as flu A, especially in high-risk populations including people over 65.

Flu A and B cause the same types of symptoms, so it’s impossible to tell which variety you have from symptoms alone. Flu B symptoms often come on quickly and last for about a week. These are the most common flu symptoms:


Cough and chest pain are common symptoms of the flu. You may experience a stuffy nose, sneezing and a sore throat, but those are less common than coughing. If you experience severe chest pain or have trouble breathing, seek medical attention.


Most people with the flu have a fever that comes on quickly and lasts for three to four days. It’s also common to experience headaches and body aches, which may be severe. You might also experience chills and feel very tired.


Although many people associate the flu with stomach symptoms like nausea and vomiting, these are rare. Children with influenza are more likely to experience stomach symptoms than adults with the flu are.

How Is Flu B Treated?

In most cases, treatment for the flu involves home remedies (including resting, staying hydrated, and sticking to mild, comforting foods, like chicken soup) and letting the virus take its course.

However, prescription antiviral medications can be used to treat the flu if it is diagnosed within the first 48 hours of symptoms. This is especially important for high-risk individuals, including people over 65, those who are pregnant, or people with other health conditions. 

Since flu B symptoms can be as severe as those caused by flu A, the Centers for Disease Control and Prevention (CDC) recommends that people over the age of 65 and other high-risk individuals use antiviral medications for flu A and flu B infections. If you feel flu symptoms coming on, call your healthcare provider as soon as possible to start treatment.

Can Flu B Be Prevented?

The best way to prevent the flu is by getting your annual flu vaccine. The flu vaccine protects against the most common flu strains. For the 2022-2023 flu season, the vaccine protects against two flu A, and two flu B strains.

In addition to getting vaccinated, you can protect yourself from the flu by practicing good hygiene, including frequent hand washing. Since the pandemic started, flu cases have been lower, suggesting that COVID precautions such as social distancing and wearing masks might also help prevent flu. 


There are two common types of flu that affect humans. Flu A and flu B. The infections are caused by different types of the influenza virus. However, they have the same symptoms and treatment. Flu B is not necessarily more mild than flu A, as previously thought.

A Word From Verywell

The treatment for flu is the same, no matter which of the flu strains you are infected with. Because of that, it’s not important whether you have flu B symptoms or flu A. Rather than worrying, take care of yourself by resting and hydrating until you begin to feel better.

If you are in a high-risk group and feel flu symptoms coming on, consider consulting your healthcare provider, who can prescribe antiviral medications. These may help speed your recovery and reduce your risk of health complications from the flu.

Frequently Asked Questions

  • Is type A or type B influenza worse?

    It’s commonly said that flu A causes worse illness than flu B. However, research from the CDC indicates both flu strains are similarly dangerous.

  • How long does it take to get rid of type B influenza?

    The flu usually lasts about a week. A fever typically runs for three to four days. After that, you’ll slowly begin to feel better. 

  • Is flu B contagious?

    Yes, flu B is contagious and easily passed from person to person. To avoid infection, practice good hygiene, including frequent hand washing. 

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. Types of influenza.

  2. Centers for Disease Control and Prevention. New CDC study compares severity of illness caused by flu A and B viruses.

  3. Centers for Disease Control and Prevention. Flu symptoms and complications.

  4. Centers for Disease Control and Prevention. Frequently Asked Influenza (Flu) Questions: 2022-2023 Season.

By Kelly Burch
Kelly Burch is has written about health topics for more than a decade. Her writing has appeared in The Washington Post, The Chicago Tribune, and more.