WHO : Influenza Update number 152

The latest influenza update from WHO, excerpt from the full report :

" Summary

• Influenza activity in the temperate regions of the northern hemisphere remains low overall though notable local increases in activity have been reported in North America, the western part of Europe, and northern China.

• Countries in the tropical zone reported low levels of influenza activity with the exceptions of southern China, Colombia, and Ecuador.

• Influenza activity in the temperate countries of the southern hemisphere is at inter-seasonal levels. The low level inter-seasonal transmission of A(H3N2) previously noted in Chile and Australia appears to be diminishing and becoming more sporadic.

• The most commonly detected virus type or subtype throughout the northern hemisphere temperate zone has been influenza A(H3N2) with the exception of China, which is reporting a predominance of influenza type B, and Mexico, where influenza A(H1N1)pdm09 is the predominant subtype circulating. In addition to Mexico, some southern states of the United States of America and Colombia in northern South America have also reported a predominance of A(H1N1)pdm09 in recent weeks.

• Nearly all influenza A viruses characterized are antigenically related to the viruses contained in the current northern hemisphere trivalent vaccine. About half of the small number of influenza type B viruses characterized are of the Yamagata lineage, which is not contained in the current vaccine.

• Oseltamivir resistance has been observed at very low levels and has not increased notably over levels reported in previous seasons."