Summary
In the temperate zone of the northern hemisphere influenza activity continued to increase.
In North America, influenza activity continued to increase in the United States of America, with influenza A(H1N1)pdm09 as the dominant subtype, followed by influenza A(H3N2).
In Europe, influenza activity remained elevated across the continent and was reported as widespread in most of the countries. Influenza A viruses co-circulated.
In North Africa, influenza activity remained elevated.
In Western Asia, influenza activity peaked is some countries and increased in other, with all seasonal influenza subtypes co-circulating.
In East Asia, influenza activity appeared to decrease overall, with influenza A(H1N1)pdm09 virus predominating.
In Southern Asia, influenza activity remained elevated overall with influenza A viruses predominating.
In the Caribbean, Central American countries, and the tropical countries of South America, influenza and RSV activity were low in general.
In the temperate zones of the southern hemisphere, influenza activity remained at inter-seasonal levels, with the exception of some parts of Australia where influenza activity remained above inter-seasonal levels.
Worldwide, seasonal influenza A viruses accounted for the majority of detections.
National Influenza Centres (NICs) and other national influenza laboratories from 115 countries, areas or territories reported data to FluNet for the time period from 04 February 2019 to 17 February 2019 (data as of 2019-03-01 05:22:16 UTC). The WHO GISRS laboratories tested more than 220347 specimens during that time period. 74302 were positive for influenza viruses, of which 73225 (98.6%) were typed as influenza A and 1077 (1.4%) as influenza B. Of the sub-typed influenza A viruses, 19600 (65.2%) were influenza A(H1N1)pdm09 and 10447 (34.8%) were influenza A(H3N2). Of the characterized B viruses, 82 (26.2%) belonged to the B-Yamagata lineage and 231 (73.8%) to the B-Victoria lineage.
The WHO Consultation and Information Meeting on the Composition of Influenza Virus Vaccines for use in the 2019-2020 Northern Hemisphere Influenza Season was held on 18-21 February 2019 in Beijing, China. It was recommended that egg based quadrivalent vaccines contain the following: an A/Brisbane/02/2018 (H1N1)pdm09 - like virus; an A(H3N2) virus to be announced on 21 March 2019*; a B/Colorado/06/2017- like virus (B/Victoria/2/87 lineage); and a B/Phuket/3073/2013 - like virus (B/Yamagata/16/88 lineage). It was also recommended that the influenza B virus component of trivalent vaccines for use in the 2019-2020 northern hemisphere influenza season be a B/Colorado/06/2017-like virus of the B/Victoria/2/87-lineage.

* In light of recent changes in the proportions of genetically and antigenically diverse A(H3N2) viruses, the recommendation for the A(H3N2) component has been postponed.