Influenza

Influenza update - 257

22 February 2016, - Update number 257, based on data up to 07 February, 2016

Summary

Globally, influenza activity in the northern hemisphere continued to increase. High levels of influenza activity have been reported in some countries in Europe. In North America, northern Africa, central and western Asia, increasing activity predominantly of influenza A(H1N1)pdm09 virus was observed. In the temperate countries of northern Asia, activity was ongoing with various proportions of circulating seasonal influenza viruses.

  • Increasing influenza A(H1N1)pdm09 activity continued to be reported in northern , eastern and southern Europe. Belarus, Greece and Ireland reported high-intensity influenza activity and Finland, the Russian Federation and Ukraine reported very high activity. Influenza A(H1N1)pdm09 viruses predominated.
  • In North America, Canada and the United States of America reported increasing activity predominantly of influenza A(H1N1)pdm09 virus. Mexico reported low levels of A(H3N2) virus activity.
  • In northern Asia, influenza activity was increasing in the Republic of Korea mainly due to influenza A(H1N1)pdm09 virus while in northern China a mixture of influenza A(H1N1)pdm09, A(H3N2) and B viruses were detected. Influenza activity in Mongolia seemed to have peaked with influenza A(H1N1)pdm09 predominating.
  • In Western Asia, influenza activity remained at high levels in Israel and Jordan. Oman reported a decrease in influenza activity.
  • In East Africa in Mauritius increasing influenza A(H1N1)pdm09 activity was reported. In northern Africa, Algeria and Morocco reported increasing influenza A(H1N1)pdm09 virus activity during this period.
  • In tropical countries of the Americas, Central America and the Caribbean, influenza and other respiratory virus activity were overall at low levels in most countries. In Cuba and Jamaica, influenza activity increased during this period.
  • In tropical Asia, countries in Southern and South East Asia continued to report ongoing low influenza activity.
  • In the temperate countries of the Southern Hemisphere respiratory virus activity remained low.
  •  National Influenza Centres (NICs) and other national influenza laboratories from 100 countries, areas or territories reported data to FluNet for the time period from 25 January 2016 to 07 February 2016 (data as of 2016-02-18 13:53:12 UTC).The WHO GISRS laboratories tested more than 154579 specimens during that time period. 38419 were positive for influenza viruses, of which 31846 (82.9%) were typed as influenza A and 6573 (17.1%) as influenza B. Of the sub-typed influenza A viruses, 20503 (86.6%) were influenza A(H1N1)pdm09 and 3163 (13.4%) were influenza A(H3N2). Of the characterized B viruses, 595 (28.4%) belonged to the B-Yamagata lineage and 1499 (71.6%) to the B-Victoria lineage.
  • A European and WHO risk assessment can be found at the links below.

Detailed influenza update

Seasonal 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.