Influenza update

13 January 2014 - Update number 202


  • In North America influenza activity has sharply increased over recent weeks. The predominant subtype of influenza viruses detected was A(H1N1)pdm09.
  • In China influenza activity has been increasing with influenza (H1N1)pdm09, A(H3N2) and influenza B circulating.
  • For the rest of the northern hemisphere as well as in the southern hemisphere influenza activity remained low.
  • In countries of tropical areas variable influenza activity was reported.
  • Based on FluNet reporting (as of 9 January 2014, 08:05 UTC), during weeks 50 to 52 (8 December 2013 to 28 December 2013), National Influenza Centres (NICs) and other national influenza laboratories from 99 countries, areas or territories reported data. The WHO GISRS laboratories tested more than 88 471 specimens. 17 640 were positive for influenza viruses, of which 15 233 (86.4%) were typed as influenza A and 2406 (13.6%) as influenza B. Of the sub-typed influenza A viruses, 6889 (67.2%) were influenza A(H1N1)pdm09, and 3365 (32.8%) were influenza A(H3N2). Of the characterized B viruses, 352 (81.1%) belong to the B-Yamagata lineage and 82 (18.9%) to the B-Victoria lineage.

Full influenza update

For regional updates on influenza see the following links

For updates on the influenza at the human-animal interface see the following WHO web pages:

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.