2021-09-12-世界卫生组织-Influenza_Update_N°_402_10页_1mb

报告摘要

Influenza Update Summary - 13 September 2021

Overview

The annual influenza activity is interpreted with caution due to the ongoing COVID-19 pandemic, which has influenced health-seeking behaviors, surveillance routines, and testing capacities globally. Influenza activity remains lower than expected for this time of year, with various factors, including public health measures, contributing to reduced transmission.

Global Influenza Activity

Despite increased testing in some countries, influenza activity is below seasonal averages.
Similar proportions of influenza A and B viruses were detected worldwide based on WHO GISRS data (62.2% A, 37.8% B).
Of influenza A viruses, 93.3% were A(H3N2), and 6.7% were A(H1N1)pdm09; B viruses were predominantly Victoria lineage (99.6%).
For the period 16-29 August 2021, 1580 specimens tested positive globally.

Regional Breakdown

Southern Hemisphere Temperate Zones (e.g., South Africa, Australia): Influenza activity at inter-seasonal levels; low or no detections in most areas, with some reports of elevated RSV activity.
Caribbean and Central America: Sporadic detections of influenza B/Victoria in Mexico; declining SARI cases, but moderate to extraordinary levels in some regions.
Tropical Africa (e.g., West, Middle, East Africa): Few detections; sporadic COVID-19 increases.
Southern Asia (e.g., India, Nepal): Rising influenza A(H3N2) detections; no change in Bangladesh.
South East Asia: No influenza detections reported.
Northern Hemisphere Temperate Zones (e.g., North America, Europe): Overall below baseline; low influenza activity, but influenza B/Victoria may increase in specific areas like southern China.

SARS-CoV-2 Influence

SARS-CoV-2 sentinel surveillance shows elevated positivity rates in sentinel specimens.
SARS-CoV-2 cases declined in some WHO regions (African and Eastern Mediterranean), while remained stable or increased in others.

Recommendations

Encourage Member States to continue influenza surveillance and share timely data to monitors, as COVID-19 may continue to affect transmission and testing.