2021-06-20-世界卫生组织-Influenza_Update_N°_396_6页_773kb

报告摘要

Influenza Update N° 396 Summary (21 June 2021)

Core Content

This report provides an overview of global influenza activity as of 6 June 2021, with data categorized by influenza transmission zones. It highlights the impact of the ongoing COVID-19 pandemic on influenza surveillance and transmission patterns.

Main Points

Global Context:
Influenza activity remained at lower levels than expected for this time of the year, despite continued or increased testing in some countries. This is attributed to the influence of the pandemic on health-seeking behaviors, testing priorities, and public health measures.
Influenza Transmission Zones:
The report divides the world into different influenza transmission zones based on geographical and epidemiological similarities.

Southern Hemisphere Temperate Zone

Oceania: Influenza-like illness (ILI) and other indicators remained very low. Influenza detections were sporadic, while other respiratory viral diseases were detected at usual levels. In one state, parainfluenza virus activity was higher than historical levels.
South Africa: Influenza B/Victoria lineage viruses were still detected, though activity remained inter-seasonal. RSV activity continued, and SARS-CoV-2 activity decreased in ILI systems but increased in pneumonia systems.
South America (Tropical): No influenza detections were reported. RSV activity was elevated in Bolivia, while SARI cases decreased in Argentina and remained low in Chile. Paraguay had extraordinary SARI levels.

Tropical Zone

Central America and the Caribbean: Only Nicaragua reported influenza detection (one B virus). SARI cases decreased in Costa Rica.
Tropical South America: No influenza detections. RSV remained elevated in Bolivia, SARI cases decreased in Ecuador, and increased in Colombia.
Tropical Africa:
- Western Africa: Influenza A(H1N1)pdm09 was detected in Côte d'Ivoire and Ghana.
- Eastern Africa: Influenza B/Victoria lineage virus was detected in Mozambique. Influenza B and increasing SARI activity were reported in Kenya.
Tropical Asia:
- Southern Asia: Influenza A(H3N2) was detected in India and Nepal; A(H1N1)pdm09 in India; B in Pakistan; and B/Victoria lineage in Bangladesh and India.
- South East Asia: No influenza detections.

Northern Hemisphere Temperate Zone

North America: Influenza indicators, including positivity and ILI activity, were at very low levels. In the USA, ILI activity in 0-4-year-olds and pneumonia/influenza mortality were above the epidemic threshold. RSV activity increased in some parts of the USA.
Europe: Influenza activity was at inter-seasonal levels with sporadic detections. ORVs were reported in some countries. EuroMOMO mortality estimates were at expected levels.
Central Asia: No influenza detections.
Northern Africa: No influenza detections.
Western Asia: Influenza and ILI activity remained low. Oman and Saudi Arabia each reported one B virus, while the UAE reported one A(H3N2) virus.
East Asia: Influenza indicators and activity remained low. ILI levels in southern China were similar to previous years (except 2019-2020), while northern China showed slightly higher levels. Influenza B/Victoria lineage detections increased in both northern and southern China but remained low compared to previous years.

Key Information

Influenza Subtypes:
- Influenza A: 69 cases (7.2%) with 24 (55.8%) being A(H1N1)pdm09 and 19 (44.2%) being A(H3N2).
- Influenza B: 896 cases (92.8%) with 830 (99.8%) being B-Victoria lineage and 2 (0.2%) being B-Yamagata lineage.
Data Sources:
- Data from 78 countries, areas, and territories were reported to FluNet.
- WHO GISRS laboratories tested over 228,646 specimens, of which 965 were positive for influenza.
Recommendations:
- WHO encourages countries, especially those with access to multiplex reagent kits, to continue influenza surveillance and testing for both influenza and SARS-CoV-2 where possible.
- Updated guidance for adapting influenza surveillance during the pandemic is available.