Past Flu Pandemics

An influenza pandemic is a global outbreak of a new influenza A virus that is very different from current and recently circulating human seasonal influenza A viruses. Influenza A viruses are constantly changing, making it possible on very rare occasions for non-human influenza viruses to change in such a way that they can infect people easily and spread efficiently from person to person. Read more about pandemics in recent history.

More Information on Past Pandemics

More information on past pandemics is available from the CDC Archive website.

Red Cross workers carring patient to ambulance
1918 Pandemic (H1N1 virus)
map of asia
1957-1958 Pandemic (H2N2 virus)
woman working in lab
1968 Pandemic (H3N2 virus)
Speaker at podium for CDC press conference
2009 H1N1 Pandemic (H1N1pdm09 virus)