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What are the Different Types of Flu Viruses?

Learn more about the different types of flu viruses, including Influenza A, B, C and D, and how they spread today.

What are the Different Types of Flu Viruses?

With the flu being one of the most common diseases, you’ve most likely had it at least once. According to the Centers for Disease Control, 3% to 11% of the U.S. population is infected by flu viruses each year. Not every flu is the same, though. Understanding the different types of flu can help you make more informed decisions about your health.

Why does the flu make me sick?

The flu is caused by a group of viruses called influenza. Once an influenza virus has entered your body, it begins to replicate in your nose and throat, causing flu symptoms.

The most common symptoms of the flu are:

  • Fever (usually occurring suddenly)

  • Cough (usually dry)

  • Muscle and joint pain

  • Headache

  • Sore throat

  • Runny nose

  • Malaise and fatigue

Most of these symptoms last about 7-10 days, although the cough may last more than 2 weeks. Flu symptoms are usually fairly mild and treatable at home. However, flu cases can also become severe and even life-threatening. This can happen to anyone. The risk increases in young children and older adults, as well as people with weakened immune systems, chronic health conditions, pregnancy or obesity.

Severe flu symptoms requiring medical attention are:

  • Shortness of breath

  • Breathing difficulty

  • Chest pain

  • Intense muscle pain

  • Severe weakness

  • Seizures

  • Lasting dizziness

  • Worsening of existing medical issues

In children, severe flu symptoms also include:

  • Gray or blue nail beds or lips

  • Dehydration

Always seek immediate medical care if you or your child have any severe symptoms of the flu.

How do flu strains spread?

The flu is highly contagious. When an infected person coughs, sneezes, or speaks, tiny influenza virus droplets fly through the air. The virus can enter your body if these droplets contact your eyes, nose, or mouth. This can also happen when you touch a surface containing an influenza virus and then touch your face. Thorough hand washing, disinfecting frequently used surfaces, and getting vaccinated can help protect you from the spread of the flu.

What are the different types of flu?

People often wonder: how many strains of flu are there? Two main types of flu affect humans. These are known as influenza A and B. Some types of flu also have variations called subtypes or lineages.

Influenza A

Influenza A is the most common form of influenza. Because influenza A viruses can live and reproduce in humans and many species of animals, they can mutate quickly. As a result, several subtypes of influenza A. Examples include H5N1 (bird flu) and H1N1 (swine flu). Influenza A circulates during the flu season and is the only type of flu that has caused pandemics.The fast evolution of influenza A viruses can make it harder for our immune systems to produce effective antibodies against them. Scientists work hard to create up-to-date vaccines that provide better protection against the flu.

Influenza B

Influenza B viruses are also very active during flu season. This type of flu only infects humans and doesn’t mutate as quickly as influenza A. While influenza B hasn’t been known to cause pandemics, it does cause outbreaks and epidemics. It tends to appear later in the flu season and is more likely to infect children.

What types of influenza cause the seasonal flu?

Influenza A and B circulate seasonally during periods of colder weather. In the United States, flu season typically occurs between October and April. Influenza A and B viruses are more active during this season – although it is possible to catch the flu at any time of the year.

How are the different types of flu treated?

No matter what types of flu are circulating or which one you have, treatment is generally the same. Most people can treat their symptoms at home without needing medical intervention. If you have mild to moderate flu symptoms, try these home remedies:

  • Keep hydrated by drinking liquids like water, juice, and soup.

  • Get extra sleep to help your body’s immune system do its work.

  • Reduce your activity levels to get more rest during the day.

  • Take painkillers if needed. Over-the-counter pain medications like acetaminophen (Tylenol) and ibuprofen (Advil) can ease headaches and body pains and reduce fevers. Note that acetylsalicylic acid (Aspirin) should never be given to children.

  • Stay home until symptoms resolve to avoid spreading the flu to others. If you need to go out in public, wear a face mask.

Treatment for at-risk groups or people with severe flu symptoms:

  • Antiviral medications can reduce the length of your illness, as well as the likelihood of complications. They are available by prescription only.

  • Hospitalization may be required in the most severe cases.

Most cases of the flu can be treated with self-care or a virtual health visit. A healthcare provider can speak with you over the phone and provide treatment advice and prescriptions if necessary.

How do I protect myself from the different types of flu?

Because there are many strains of the flu, immunity to one type of influenza does not result in immunity to the others. This means that if you catch the flu early in the season, you can still catch a different type of flu later in the season. Your body won’t have the antibodies needed to protect against the different strains. The best way to protect against all different types of flu is by getting a flu vaccine. The flu vaccine will help your body produce antibodies for multiple influenza viruses.

Influenza viruses often mutate, and different subtypes and lineages circulate at different times. This means immunity from an infection or vaccination last season might not be as effective this season. Scientists update vaccines annually to help make them more effective for the current year’s influenza strains. Getting a flu shot annually helps keep your body up to date with the most protective antibodies.

Other flu prevention measures include washing your hands often, disinfecting frequently touched items like phones and toys, covering your mouth when you sneeze or cough, and staying home when sick.

Need treatment for the flu? Schedule a virtual visit today

Do you have questions about the flu? You can get easy answers to your healthcare questions with WellNow. With virtual care available 24/7, you can speak with a provider from the comfort of your own home, anytime you need it. Feel better, faster with WellNow. Start your virtual visit now or walk into any of our urgent care locations!

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Information contained in this blog is for informational or educational purposes only and does not substitute professional medical advice or consultations with healthcare professionals. The content is not meant to be complete or exhaustive or to apply to any specific individual's medical condition. Always refer to the personalized information given to you by your doctor or contact us directly.