What are the types of Flu?

1. Influenza A

* Causes the most severe illness and is responsible for most flu pandemics.

* There are three types of influenza A viruses that can cause illness in humans:

* H1N1

* H2N2

* H3N2

* Influenza A viruses are constantly changing, so new strains emerge every year.

* This is why it's important to get a flu vaccine every year, to protect against the most recent strains.

2. Influenza B

* Causes less severe illness than influenza A, and is less likely to lead to hospitalization or death.

* There are two types of influenza B viruses that can cause illness in humans:

* Yamagata

* Victoria

* Influenza B viruses also change over time, but not as quickly as influenza A viruses.

* This is why it's possible to get the same strain of influenza B virus more than once.

3. Influenza C

* Causes mild illness that is usually limited to the respiratory tract.

* Influenza C viruses are not as common as influenza A and B viruses, and they do not cause pandemics.

* There are only a few strains of influenza C virus that can cause illness in humans.

* Influenza C viruses do not change very often, so it's possible to get the same strain of influenza C virus more than once.

4. Other respiratory viruses

* In addition to influenza viruses, there are a number of other respiratory viruses that can cause flu-like symptoms.

* These include:

* Respiratory syncytial virus (RSV)

* Parainfluenza virus

* Adenovirus

* Metapneumovirus

* These viruses can cause illness in people of all ages, but they are most common in children.