WHO: Pandemic (H1N1) 2009 – Weekly update 77: 4 December 2009

The WHO continues to issue weekly “updates” and briefing notes as below:

Pandemic (H1N1) 2009 – update 77
Weekly update

4 December 2009 –
As of 29 November 2009, worldwide more than 207 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including at least 8768 deaths.

As many countries have stopped counting individual cases, particularly of milder illness, the case count is likely to be significantly lower than the actual number of cases that have occurred. WHO is actively monitoring the progress of the pandemic through frequent consultations with the WHO Regional Offices and member states and through monitoring of multiple sources of data.

Situation update:

In the temperate zone* of the northern hemisphere, the early arriving winter influenza season continues to intensify across central Europe and in parts of central, eastern, and southern Asia. Disease activity has peaked and is declining in North America and has either recently peaked or is currently peaking in much of western and northern Europe.

In both Canada and the United States, influenza virus circulation remains active and geographically widespread, however, disease activity appears to have peaked in past 3 to 4 weeks. In the United States, deaths due to pneumonia and influenza (P&I mortality) continued to increase past the epidemic threshold for the past 8 weeks and cumulative rates of hospitalizations for the current influenza season have exceeded rates seen in recent seasons among all age groups except those aged ≥ 65.

In Europe, widespread and intense transmission of pandemic influenza virus continued to be observed across most of the continent. In western and northern Europe the peak of disease activity has passed in Belgium, Iceland, Ireland, Netherlands, Norway and parts of the United Kingdom (Northern Ireland, Wales); activity may be peaking or plateauing in Spain, Portugal, Italy, Sweden and Denmark. Influenza activity continues to increase in much of Central Europe in the region between the Baltic and Balkan countries and from Germany to Romania. In Eastern Europe, recent peaks or plateaus in disease activity have also been observed in Ukraine, Belarus, Bulgaria and the Republic of Moldova. In the Russian Federation, influenza activity remains active and intense in some regions, with an overall increasing trend. A moderate impact on the healthcare system has been reported in parts of Northern and Eastern Europe. Over 99% of subtyped influenza A viruses in Europe were pandemic H1N1 2009.

In Western and Central Asia, influenza transmission remains active. Disease activity continues to increase in Kazakhstan, Kyrgyzstan, Uzbekistan, Iran and Iraq, while activity may have peaked in Israel, Jordan, and Afghanistan.

In East Asia, increasing ILI** or respiratory disease activity has been reported in Southern China and Japan. A recent decline in activity has been observed in Northern China. In South and Southeast Asia, influenza activity continues to increase in the north-western parts of India, Nepal, Sri Lanka, and Cambodia, while activity in the rest of region remain low.

In the tropical zone of Central and South America and the Caribbean, influenza transmission remains geographically widespread but overall disease activity has been declining except for focal areas of increasing activity in Jamaica, Venezuela, and Ecuador.

In Africa, pandemic H1N1 2009 virus continues to be isolated from all parts of the continent, and there is evidence of continued co-circulation of pandemic (H1N1) 2009 and seasonal H3N2 viruses.

In the temperate region of the southern hemisphere, little pandemic influenza activity has been reported.

The Global Influenza Surveillance Network (GISN) continues monitoring the global circulation of influenza viruses, including pandemic, seasonal and other influenza viruses infecting, or with the potential to infect, humans including seasonal influenza. For more information on virological surveillance and antiviral resistance please see the weekly virology update (Virological surveillance data, below).


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