2023-05-14-世界卫生组织-Influenza_Update_N°_445_12页_1mb

报告摘要

Influenza Update N° 445 Summary (15 May 2023)

Core Content

This update provides an overview of global influenza and SARS-CoV-2 surveillance data as of 30 April 2023, with a focus on the co-circulation of both viruses and their impact on public health. It also includes information on respiratory syncytial virus (RSV) where available. The report highlights the importance of integrated surveillance and timely reporting to global platforms like FluNet.

Main Recommendations

Countries are advised to monitor the co-circulation of influenza and SARS-CoV-2 and report to RespiMART (FluNet and FluID) directly or through regional platforms.
Southern hemisphere countries are encouraged to step up their influenza vaccination campaigns to prevent severe disease and hospitalizations.
Clinicians should consider influenza in the differential diagnosis, especially for high-risk groups, and follow national and WHO guidance for testing and treatment.

Global Influenza Activity

Global influenza detections decreased further due to a decline in the northern hemisphere, while some southern hemisphere countries reported increases.
Influenza B viruses predominated in most regions, including North America, Europe, and East Asia.
Influenza A(H1N1)pdm09 was the most common subtype detected in several regions, including Europe and East Asia.
Influenza activity was low in Central Asia, Northern Africa, and Western Asia.
RSV activity was generally low globally, except in Australia and parts of the Americas, where it remained elevated in some areas.

SARS-CoV-2 Surveillance

Global SARS-CoV-2 positivity from sentinel surveillance increased to 17%, with higher levels in the Eastern Mediterranean and Western Pacific regions.
Non-sentinel SARS-CoV-2 positivity was reported at around 30% globally.
WHO encourages integrated influenza and SARS-CoV-2 surveillance to better understand co-circulation and public health impact.

Influenza Data by Region

North America

Influenza activity was low, with most indicators at inter-seasonal levels.
Influenza B viruses were predominant in Canada and the USA.
Influenza-associated pediatric hospitalizations remained low, though there was a recent increase due to B viruses.
RSV activity was low in both countries.

Europe

Overall influenza detections decreased, with sentinel positivity below the 10% epidemic threshold.
Influenza B viruses predominated in sentinel and non-sentinel surveillance.
Influenza activity was low in most countries, with a few reporting medium or widespread activity.
Pooled all-cause mortality estimates from EuroMOMO showed no excess mortality.
Influenza B viruses were predominant in most subregions, with some countries reporting A(H1N1)pdm09 as the main subtype.

East Asia

Influenza activity decreased overall, with A(H1N1)pdm09 predominant.
In Hong Kong SAR, influenza positivity and hospital admission rates increased.
In the Republic of Korea, influenza activity increased slightly.
In Japan, influenza activity remained low.

South-East Asia

Influenza activity decreased, with Malaysia reporting lower detections.
Influenza A viruses predominated in Malaysia, with equal proportions of A(H1N1)pdm09 and A(H3N2).
In Singapore, ARI rates remained elevated with A(H3N2) as the main subtype.

Tropical Countries (Central America, Caribbean, and South America)

Influenza activity was generally low, with B/Victoria lineage viruses predominant.
In Guatemala, influenza activity returned below the epidemic threshold, while SARI cases increased.
In Bolivia, influenza positivity reached an extraordinary level with A(H1N1)pdm09 predominant.
In Brazil, influenza B and A(H1N1)pdm09 co-circulated.
RSV activity was elevated in Bolivia, Brazil, and Colombia.

Tropical Africa

Influenza detections were low across reporting countries.
Influenza A(H1N1)pdm09 was predominant in Western Africa.
In Middle Africa, low detections were reported in Cameroon.
In Eastern Africa, activity remained low, with ILI returning to baseline in Mayotte.

Temperate Southern Hemisphere

Influenza activity remained low in most countries, though there were slight increases in Australia and Chile.
Influenza A viruses were predominant, with A(H1N1)pdm09 most common.
In South Africa, influenza activity increased slightly in pneumonia surveillance.
RSV and SARS-CoV-2 activity increased in Chile and Paraguay.

Key Information

Total specimens tested by WHO GISRS laboratories globally from 17 April to 30 April 2023: 266,317.
Influenza-positive specimens: 18,330 (77.52% A, 22.48% B).
Subtyped influenza A viruses: 8816 (A(H1N1)pdm09) and 3854 (A(H3N2)).
Subtyped influenza B viruses: All 587 belonged to the B/Victoria lineage.
SARS-CoV-2-positive specimens from sentinel surveillance: 6,835 (15.35%).
Non-sentinel SARS-CoV-2-positive specimens: 16,706.

Additional Notes

The report emphasizes the importance of timely and consistent reporting to FluNet for accurate surveillance.
RSV and SARS-CoV-2 activity is included in the update where available, highlighting their co-circulation with influenza.
Data completeness and quality may vary due to the availability of information at the time of the update.