Here's Everything You Need to Know About the 3 Different Types of Flu Viruses Coming Your Way

Updated on 9/30/2018 at 8:20 PM

One day you're feeling great, the next day you're coughing, and before you know it, you've got the flu virus — now would be the perfect time to knock on wood.

According to the Center For Disease Control, contracting the flu virus is most common during the Fall and Winter. Typically, flu activity begins to increase in October and peaks between December and February, although it can unfortunately last until May.

While there are four viruses in total — A, B, C, and D — only the first three affect humans. Flu D primarily affects cattle and is not known to infect people, so you don't need to bother yourself worrying about that one. As one of the most common illnesses, the CDC also reports that between 9.2 and 35.6 million people become ill from the flu each year in the US.

The flu is spread through droplets created whenever people sneeze, speak, or cough and can infect people in up to a six-foot radius. If you come into contact with a surface or object that has the flu virus on it, and then touch your mouth, nose, or eyes, you are also at risking of catching the flu. The virus can "live" for up to 48 hours depending on the surface — this fact has us washing our hands frequently during flu season.

To prevent catching the flu, experts advise getting a flu shot before the flu seasons begins. As always, avoid contact with sick people, and if you're sick, try limit your contact with those who are not ill. If you do have flu-like symptoms, the CDC recommends staying home for 24 hours after your fever breaks. Like you learned when you were a toddler, always cover your nose and mouth when you sneeze (sneeze and cough into your elbow), and wash your hands thoroughly and often.

Now it's time to learn the "A"s, "B"s, and "C"s of various types of flu.

Influenza A

Type A virus can affect animals, but most commonly affects people. This virus is typically responsible for the larger flu epidemics and is spread by people who are already infected. According to the CDC, "The emergence of a new and very different influenza A virus to infect people can cause an influenza pandemic." Since the flu strain is new, people don't have immunity to it so it can spread quickly.

Influenza A viruses are divided into subtypes determined by the two proteins found on the surface of the virus: hemagglutinin (H) and the neuraminidase (N). Currently, there are 18 different hemagglutinin subtypes and 11 different neuraminidase subtypes.

The Type A flu virus can be further broken down into strains. The H1N1 and H3N2 strains are found in people, and in 2009, the CDC found that a new H1N1 virus (also known as 2009 H1N1) causes illness in people and caused the first flu pandemic in 40 years.

Influenza B

Unlike influenza Type A, the B viruses are not broken down into subtypes, but can be broken down into lineage and strains. According to the CDC, the two B strains in circulation belong to either the B/Yamagata lineage or the B/Victoria lineage.

Influenza B is only found in humans and may be less severe than Type A, but it's still harmful. The Type B virus typically does not cause a pandemic.

Influenza C

Of the three viruses that affect humans, Influenza Type C is the mildest, and most people don't become very ill from it. The CDC states that the Type C virus generally causes mild respiratory illness and does not cause epidemics.

If you do come down with the flu, do take care of yourself by getting plenty of rest and drinking ample fluids. In the meantime, wash your hands.