2021-12-19-世界卫生组织-Influenza_Update_N°_409_11页_1mb

Influenza activity globally remains low but is increasing, primarily in temperate zones of the northern hemisphere, due to COVID-19 pandemic impacts that reduced transmission and affected surveillance but also emphasized the need for integrated monitoring.

Influenza A predominates, with A(H3N2) the most common subtype (accounting for 90.1% of subtyped A viruses), alongside B strains primarily of the Victoria lineage.

Regional summaries: North America shows low but rising activity, Europe is experiencing increases mainly driven by A(H3N2), East Asia continues slow growth with low indicators, the Caribbean and Central America report sporadic detections, Tropical Africa shows a decreasing trend, Southern Asia has declining detections, South-East Asia saw a single detection in the Philippines, and the southern hemisphere remains low with some RSV activity noted.

SARS-CoV-2 co-circulation is ongoing, with decreasing positivity rates in many areas, highlighting the reduction in transmission likely linked to pandemic measures.

WHO recommends enhancing integrated influenza and COVID-19 surveillance, increasing vaccination efforts in high-risk groups, and ensuring timely reporting based on routine surveillance data.