Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to site content Skip directly to page options
CDC Home

2009 H1N1 Flu: International Situation Update

This website is archived for historical purposes and is no longer being maintained or updated. For updated information on the current flu season, see the CDC Seasonal Flu website.

December 18, 2009, 3:30 PM ET

This report provides an update to the international situation as of December 18, 2009. The World Health Organization (WHO) continues to report laboratory-confirmed 2009 H1N1 flu cases and deathsExternal Web Site Icon on its Web page. These laboratory-confirmed cases represent a substantial underestimation of total cases in the world, as most countries focus surveillance and laboratory testing only on people with severe illness. The 2009 H1N1 influenza virus continues to be the dominant influenza virus in circulation in the world. For the most recent period in which data are available, from November 15 to December 5, 2009, 92.2% of influenza specimens reported to WHO were 2009 H1N1, 1% were seasonal A (H1), 0.9% were A (H3), 5.2% were influenza A viruses that were not subtyped, and 0.8% were influenza B viruses. In temperate regions of the Southern Hemisphere, sporadic cases of 2009 H1N1 have been reported in recent weeks but no sustained transmission has been observed. In tropical regions of the Americas and Asia, influenza activity due to 2009 H1N1 remains variable. In temperate regions of the Northern Hemisphere, influenza-like illness (ILI) activity due to 2009 H1N1 has passed its peak in North America and in parts of Western and Northern Europe, but activity continues to increase in parts of Central and Southeastern Europe, as well as in South and Central Asia.

Selected Highlights

  • The 2009 H1N1 influenza virus is the predominant influenza virus in circulation worldwide.
  • The epidemiology of disease caused by 2009 H1N1 influenza in the Southern Hemisphere is very similar to that described in the United States in the spring of 2009.
  • According to WHO, the majority of 2009 H1N1 influenza isolates tested worldwide remain sensitive to oseltamivir, an antiviral medicine used to treat influenza disease. 136 2009 H1N1 isolates tested worldwide have been found to be resistant to oseltamivir – 44 of these isolates were detected in the United States.
  • On September 17, 2009, several countries including the United States announced plans to donate 2009 H1N1 vaccine or funds to support vaccination campaigns in less developed countries.

International Resources for 2009 H1N1 Information

Health Organizations

World Health Organization (WHO) Regional Offices

Travel and 2009 H1N1 Flu

Human cases of 2009 H1N1 flu virus infection have been identified in the United States and several countries around the world. For information on 2009 H1N1 flu and travel, see the CDC H1N1 Flu and Travel website.

Reports and Publications

 
Contact Us:
  • Centers for Disease Control and Prevention
    1600 Clifton Rd
    Atlanta, GA 30333
  • 800-CDC-INFO
    (800-232-4636)
    TTY: (888) 232-6348
  • Contact CDC-INFO
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Centers for Disease Control and Prevention   1600 Clifton Rd. Atlanta, GA 30333, USA
800-CDC-INFO (800-232-4636) TTY: (888) 232-6348 - Contact CDC–INFO
A-Z Index
  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #