On June 11, 2009, in response to the global spread of a new strain of influenza, the World Health Organization (WHO) declared the outbreak to be an influenza pandemic, the first since 1968. The new influenza virus and pandemic was named "Pandemic (H1N1) 2009."

In Ontario, the pandemic occurred in two waves. The first wave peaked in spring 2009, the second in fall/winter 2009.

The H1N1 influenza virus is expected to circulate for years as a regular seasonal influenza strain.

Read more on seasonal influenza

The WHO declared the H1N1 pandemic over on August 10, 2010.

For more information:

• H1N1 Flu Virus General Fact Sheet. (PDF) Huron County Health Unit, October 27, 2009.
• How Ontario Fared: A Report by Ontario's Chief Medical Officer of Health. (PDF) Ministry of Health and Long-Term Care, June 2, 2010.
• The Pandemic H1N1 flu is a different flu. Ontario Ministry of Health and Long-Term Care.

Government of Canada

• Canadian Pandemic Influenza Plan for the Health Sector.
• FightFlu.ca
• Your H1N1 Preparedness Guide. (PDF) Public Health Agency of Canada, 2009.

Archived Weekly Surveillance Bulletins