Table 1. . Main characteristics of Russian-, Spanish-, Asian-, Hong-Kong-, Swine influenza pandemics, including the virus strain involved, the geographical area of onset, the clinical impact in distinct regions of the globe and the death rate in the general population or in the different age classes.

Name of pandemic	Virus strains	Date of onset/duration	Waves/period of onset (n)	Suspected origin of epidemic	Estimated world population	Estimated infected population	Deaths in the world (n)	Case fatality rates	Ref.
‘Russian’ pandemic influenza	Likely H3N8 or H2N2 Or Corona-virus OC43	1889 1889–1894	4 waves First: October 1889–December 1890; Second: March–June 1891; Third: November 1891–June 1892; Fourth: winter 1893–1894	Russia	1.5 billion	300–900 million	1 million	0.1–0.3%	[100,104,106]
‘Spanish’ pandemic influenza	H1N1	1918 1918–1920	4 waves First: March 1918 Second: second half of August 1918 Third: January–June 1919 Fourth: January–April 1920	China	1.8 billion	500 million–1 billion	17–50 million	2–3% Until 10%	[96,98,103]
Asian influenza	H2N2	1957 1957–1958	2 waves First: October–December 1957 Second: January–March 1958 Recurrences of H2N2 virus associated pandemic in: January–March 1960 January–March 1963	China	3 billion	About 500 million	1.1 million	0.2–0.3%	[95,102,105]
Hong Kong influenza	H3N2	1968 1968–1970	2 waves First: July 1968–April 1969 Second: November 1969–March 1970	Hong Kong	3.5 billion	About 500 million	1–4 million	0.1–0.3%	[94,97]
Swine influenza	H1N1/09	2009 2009–2010	2/3 waves First: April–July 2009 Second: August 2009–March 2010. Third: November/December 2010–February 2011	Mexico	6.8 billion	About 700 million–1.4 billion	151,000–575,000	0.01%	[99,101]