2022-01-09-世界卫生组织-Influenza_Update_N°_410_11页_1003kb

Influenza Update Summary (January 10, 2022)

This report analyzes global influenza surveillance data up to December 26, 2021, based on data from the World Health Organization's Global Influenza Surveillance and Response System (GISRS). The ongoing COVID-19 pandemic has influenced interpretations due to changes in health-seeking behaviors, surveillance routines, and transmission reduction measures, which may have reduced influenza spread.

Key Highlights

• Interpretation Caution: Data should be viewed carefully, as pandemic-related factors have impacted influenza surveillance and testing capacities.
• Global Activity: Influenza activity remains low in many regions but is increasing, particularly in northern hemisphere temperate zones, reaching or exceeding levels seen before the pandemic in some countries. Co-circulation with SARS-CoV-2 is emphasized.
• Dominant Strains: Influenza A(H3N2) is predominant in most areas, with Influenza B-Victoria lineage showing growth in some regions like East Asia.
• SARS-CoV-2 Impact: SARS-CoV-2 sentinel surveillance shows high positivity (approximately 30% in some areas), highlighting increased detections during the pandemic.

Regional Influenza Activity

• Northern Hemisphere Temperate Zones: Activity increased, with A(H3N2)-predominated cases reported widely, including in North America and Europe. North America saw low but rising detections; Europe experienced sharp increases crossing seasonal thresholds.

• East Asia: Influenza activity is rising, driven largely by China, where B-Victoria lineage dominates and activity is similar to pre-pandemic levels. Surrounding areas remain low.

• Tropical Regions: Variable trends include decreases in tropical Africa with some fluctuations, stability in Asia, and increases in South America with A(H3N2) predominance.

• Southern Hemisphere: Overall low activity persists, but reports from South America indicate increases in some countries, mostly A(H3N2) detections.

Recommendations

• Countries should enhance integrated surveillance for influenza and SARS-CoV-2, strengthen vaccination campaigns, and integrate influenza into differential diagnosis for severe respiratory cases to prevent hospitalizations.

• The global community is encouraged to monitor influenza closely, especially in regions with co-circulation, and report data promptly to regional WHO platforms.