The type A viruses are the most virulent human pathogens among the three influenza types and causes the most severe disease. The serotypes that have been confirmed in humans, ordered by the number of known human pandemic deaths, are H1N1, H2N2, H3N2, H5N1 and H7N7 just to name a few. Below is a chart on the latest flu pandemics.

Chart on latest flu pandemics

Name of pandemic	Date	Deaths	Subtype involved
Asiatic(Russian) Flu	1889-90	1 million	possibly H2N2
Spanish Flu	1918-20	40 million	H1N1
Asian Flu	1957-58	1 to 1.5 million	H2N2
Hong Kong Flu	1968-69	0.75 to 1 million	H3N2

Elderly and premmies are more immunocompromise, therefore they are more likely to get infected with influenza. Similar to rhinovirus, influenza occurs throughout the year. It has short incubation period of 1-4 days. There are few serotypes circulating simultaneously like rhinovirus. Take flu vaccine or antiviral medicines as treatment for influenza. Most importantly is drinking lots of water and have plenty of rest.

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