2021-12-05-世界卫生组织-Influenza_Update_N°_408_11页_1mb

Influenza Update N° 408: Globally, influenza activity remained below levels of previous years. Aspects: COVID-19 reduced health-seeking behaviors and influenced surveillance, potentially affecting data, but not completely suppressing influenza circulation. Based on data up to 21 November 2021, reported on 6 December 2021.

In temperate Northern Hemisphere (NA) zones, overall activity below baseline. Canada: ILI below expected, RSV elevated. USA: ILI stable, Atypical ILI? ILI activity low but slightly increased. ILI activity rose but remained below national threshold. Influenza detections increased but stayed low, with H3N2 predominant. Pneumonia, Influenza & COVID-19 deaths remained above epidemic threshold; RSV elevated in parts of Canada and decreased in USA.

In Europe (Europe), activity generally low, similar to prepandemic levels in some countries (e.g., non-primary reporting) non-primary). Pooled EuroMOMO data showed a slight increase but uneven; Wales saw high excess mortality likely linked to COVID-19. Dominated by H3N2 in many countries. RSV levels mixed.

In Asia: North Asia saw very few cases; Subtypes involved. Reduced intensity compared to prior winters. Central Asia: some detections of A(H3N2) and subtype N1pdm09. Influenza decreased in some Eastern/Southern/Western Asia countries (e.g., SE Asia reported few new cases maybe placeholder). Southern/Oceania Asia: Indonesia? Indonesia Not specified, no data from. Influenzase - some countries like in Southern Asia saw steep increases in B-type in China.

In Africa (Africa): West Africa: A predominated, including H1N1pdm09 in several countries. Mostly A viruses detected across Middle/Southern/Western Africa. Eastern Africa: A and B detected similarly; Mayotte had an influenza-like activity increase possibly indicating a delayed pre-epidemic period.

In the Southern Hemisphere (SH): Globally NA overall influenza activity low. Oceania: activity remained low despite testing. South Africa: detection rates stable or increasing locally but overall still low. SH Americas: Paraguay reported single episodes of A(H3N2); activity lower than previous years.

Boosters: COVsCoVI19 data mentioned separately among other things. High sensitivity for COVID and reduced ACE2 availability.