WHO | Influenza update – 325

Information in this report is categorized by influenza transmission zones, which are geographical groups of countries, areas or territories with similar influenza transmission patterns. For more information on influenza transmission zones, see the link below:


In the temperate zones of the southern hemisphere, influenza activity appeared to decrease in South America and Southern Africa. Influenza activity remained at low seasonal levels in Australia and New Zealand and at inter-seasonal levels in most of temperate zone of the northern hemisphere. Increased influenza detections were reported in some countries of Southern and South-East Asia. Worldwide, seasonal influenza subtype A viruses accounted for the majority of detections.

National Influenza Centres (NICs) and other national influenza laboratories from 85 countries, areas or territories reported data to FluNet for the time period from 03 September 2018 to 16 September 2018 (data as of 2018-09-28 04:54:34 UTC). The WHO GISRS laboratories tested more than 68731 specimens during that time period. 2512 were positive for influenza viruses, of which 2120 (84.4%) were typed as influenza A and 392 (15.6%) as influenza B. Of the sub-typed influenza A viruses, 1104 (65.3%) were influenza A(H1N1)pdm09 and 586 (34.7%) were influenza A(H3N2). Of the characterized B viruses, 54 (55.1%) belonged to the B-Yamagata lineage and 44 (44.9%) to the B-Victoria lineage.

The WHO Consultation and Information Meeting on the Composition of Influenza Virus Vaccines for Use in the 2019 Southern Hemisphere Influenza Season was held on 24-26 September 2018 in Atlanta, United States of America. It was recommended that trivalent vaccines contain the following: an A/Michigan/45/2015 (H1N1)pdm09-like virus; an A/Switzerland/8060/2017 (H3N2)-like virus; and a B/Colorado/06/2017-like virus (B/Victoria/2/87 lineage). It was also recommended that quadrivalent vaccines containing two influenza B viruses contain the above three viruses and a B/Phuket/3073/2013-like virus (B/Yamagata/16/88 lineage).
The vaccine recommendation for the 2019 Southern Hemisphere Influenza Season can be consulted at this link below:

Source: WHO | Influenza update – 325