Influenza

Influenza update

22 September 2014 - Update number 220

Summary

Globally the influenza season was ongoing in the southern hemisphere. Elsewhere influenza activity remained low, except for some tropical countries in the Americas.

  • In Europe and North America, overall influenza activity remained at inter-seasonal levels.
  • In tropical countries of the Americas, influenza B was predominant with co-circulation of respiratory syncytial virus (RSV).
  • In Africa (with exception of the southern cone) and western Asia, influenza activity was low.
  • In eastern Asia, influenza activity remained low in most countries with influenza A(H3N2) the main detected virus subtype. Influenza A(H3N2) and B activity continued in south China.
  • In the southern hemisphere, the influenza season was ongoing. In the temperate zone of South America, influenza activity associated mainly with A(H3N2) viruses decreased. In Australia and New Zealand, the influenza season was ongoing. Australia reported continued high activity associated with A(H1N1)pdm09 and A(H3N2) viruses. In South Africa the influenza season continued with A(H3N2) predominating.
  • Based on FluNet reporting (as of 18 September 2014 15:50 UTC), during weeks 35 to 36 (24 August 2014 to 6 September 2014), National Influenza Centres (NICs) and other national influenza laboratories from 50 countries, areas or territories reported data. The WHO GISRS laboratories tested more than 22 607 specimens. 2675 were positive for influenza viruses, of which 2168 (81%) were typed as influenza A and 507 (19%) as influenza B. Of the sub-typed influenza A viruses, 529 (30.1%) were influenza A(H1N1)pdm09 and 1231 (69.9%) were influenza A(H3N2). Of the characterized B viruses, 66 (98.5%) belonged to the B-Yamagata lineage and 1 (1.5%) to the B-Victoria lineage.

Full influenza update


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Source of data

The Global Influenza Programme monitors influenza activity worldwide and publishes an update every two weeks.
The updates are based on available epidemiological and virological data sources, including FluNet (reported by the WHO Global Influenza Surveillance and Response System) and influenza reports from WHO Regional Offices and Member States. Completeness can vary among updates due to availability and quality of data available at the time when the update is developed.

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