Global Alert and Response (GAR)

Pandemic (H1N1) 2009 - update 107

Weekly update

As of 27 June, worldwide more than 214 countries and overseas territories or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including over 18239 deaths.

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 information.

Situation update:

Summary: Worldwide, overall pandemic and seasonal influenza activity remains low. In the temperate regions of the Southern Hemisphere, Chile, and Argentina report low activity and only sporadic detections of both pandemic and seasonal influenza viruses during the early part of winter. South Africa, New Zealand, and Australia have all recently noted slight increases in the rate of respiratory disease. South Africa recently reported their first case of confirmed H1N1; however, the predominant influenza virus there currently is seasonal influenza A(H3N2). The H3N2 virus detected in South Africa is similar to the Perth-like strain, which is currently a component of the trivalent seasonal influenza vaccine. Active transmission of pandemic influenza virus still persists in localized areas of the tropics, particularly in South and Southeast Asia, the Caribbean and West Africa. During the last 2 to 3 weeks, seasonal influenza H3N2 viruses have also been detected at increasing levels in Nicaragua, and low levels or sporadically in Australia, Central America, South Africa and East Africa. Global circulation of seasonal influenza virus type B viruses persists at low levels in parts of East Asia, Central Africa, and Central America.

Regional Details: In most countries of the temperate zone of the southern hemisphere (Chile, Argentina, South Africa, Australia, and New Zealand) pandemic and seasonal influenza viruses have been detected only sporadically in June 2010 and activity is low, indicating a late start of the influenza season compared to 2008. Overall levels of respiratory disease in the population remain low. In Argentina, small numbers of influenza type B viruses were detected during mid June 2010. In both Chile and Argentina, respiratory syncitial virus (RSV) continued to be the predominant circulating respiratory virus resulting in high rates of respiratory illness in children. In South Africa, small and slightly increasing numbers of seasonal H3N2 and type B viruses were detected during mid June 2010. In both Australia and New Zealand, levels of ILI are increasing, but still below recent historical seasonal levels.

In Asia, the most active areas of pandemic influenza virus transmission currently are in parts of southern India, Bangladesh, Singapore, and Malaysia. Rates are decreasing in the latter three countries but in India, the number of laboratory confirmed cases of pandemic influenza has increased since mid June. This activity has been primarily observed in Southern state of Kerala, and includes reports of a number of severe and fatal cases, particularly among pregnant women. In Bangladesh, pandemic and seasonal influenza type B viruses co-circulated at low levels during early June 2010. In Singapore, during the third week of June 2010, the levels of ARI remained below warning levels and the proportion of patients with ILI testing positive for pandemic influenza virus fell from 19% to 15%. In Malaysia, data suggests that overall pandemic influenza activity has declined throughout June 2010 though pandemic virus continues to circulate at low levels. Throughout East Asia, influenza activity remained very low. In China and Japan, levels of ILI remained at or below baseline levels for the summer months. Low and declining levels of influenza type B viruses continued to circulate across China, Hong Kong SAR (China), Chinese Taipei and Republic of Korea.

In the tropical regions of the Americas, overall pandemic and seasonal influenza activity remained very low. In Cuba, pandemic influenza virus transmission remains active but has declined substantially since peaking during mid-April to mid-May 2010; no new fatal cases have been reported over the past five reporting weeks. In several countries of the region, there has been recent circulation of seasonal influenza A (H3N2) viruses (Venezuela during May 2010) and B viruses (Bolivia during March and May 2010; El Salvador during late May and early June 2010). Nicaragua notably has seen a sharp increase in the detection of seasonal influenza A (H3N2) and Panama has detected low numbers of the same. In addition, after 20 weeks with no circulating pandemic virus, Panama reported the detection of pandemic influenza (H1N1) 2009 in early June. Many countries in the area also report ongoing co-circulation of other respiratory viruses, most notably RSV.

In sub-Saharan Africa, pandemic and seasonal influenza activity has been observed in several countries. Ghana, in West Africa, continues to have active circulation of pandemic influenza virus several weeks after activity peaked during early April 2010. Seasonal influenza type B viruses continue to circulate in parts of central and southern Africa, most notably in Cameroon. As reported in previous updates, small numbers of seasonal H3N2 viruses continue to be detected across Africa, particularly in eastern Africa; the most recent detections have been reported in Ghana, Kenya, and South Africa during mid June 2010. The persistence of H3N2 in this area over time very likely represents sustained community transmission of the virus.

Overall, in the temperate regions of the northern hemisphere (North America and Europe), pandemic and seasonal influenza viruses have been detected sporadically or at very low levels during the past month.

*Countries in temperate regions are defined as those north of the Tropic of Cancer or south of the Tropic of Capricorn, while countries in tropical regions are defined as those between these two latitudes.

**Abbreviations: influenza-like-illness (ILI), acute respiratory infection (ARI), and severe acute respiratory infection (SARI)

MAP OF INFLUENZA ACTIVITY AND VIRUS SUBTYPES (WEEK 24: 13 JUNE - 19 JUNE 2010)

  • Map of influenza activity and virus subtypes
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    Description: Displayed data reflect the most recent data reported to Flunet (www.who.int/FluNet), WHO regional offices or on Ministry of health websites in the last 2 weeks. The percent of specimens tested positive for influenza includes all specimens tested positive for seasonal or pandemic influenza. The pie charts show the distribution of virus subtypes among all specimens that were tested positive for influenza. The available country data were joined in larger geographical areas with similar influenza transmission patterns to be able to give an overview (http://www.who.int/csr/disease/swineflu/transmission_zones/en)

Qualitative indicators (Week 29 to Week 24: 13 July 2009 - 19 June 2010)

The qualitative indicators monitor: the global geographic spread of influenza, trends in acute respiratory diseases, the intensity of respiratory disease activity, and the impact of the pandemic on health-care services.

The maps below display information on the qualitative indicators reported. Information is available for approximately 60 countries each week. Implementation of this monitoring system is ongoing and completeness of reporting is expected to increase over time.

Geographic spread of influenza activity
Trend of respiratory diseases activity compared to the previous week
Intensity of acute respiratory diseases in the population
Impact on health care services
Laboratory-confirmed cases of pandemic (H1N1) 2009 as officially reported to WHO by States Parties to the IHR (2005) as of 20 June 2010

The countries and overseas territories/communities that have newly reported their first pandemic (H1N1) 2009 confirmed cases since the last web update (No. 106): none.

The countries and overseas territories/communities that have newly reported their first deaths among pandemic (H1N1) 2009 confirmed cases since the last web update (No. 106): none.

*The reported number of fatal cases is an under representation of the actual numbers as many deaths are never tested or recognized as influenza related

**No update since 7 March 2010

***No update since 23 May 2010

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