Influenza Update N° 526

Overview

^{Published 14 May 2025 | For reporting Week 18, ending 04 May 2025}

Influenza

• In the Northern hemisphere, influenza positivity continued to decline or remained stable in most countries. Influenza positivity remained elevated in a few countries in Central America and the Caribbean, Tropical South America, and in Western Africa (predominantly A(H1N1)pdm09), Eastern Africa and Europe (predominantly A viruses), in Western Asia (seasonal influenza viruses of all subtypes), Southern Asia (predominantly A(H3N2)), Eastern and South-East Asia (predominantly A viruses).
• In the Southern hemisphere, influenza positivity increased or remained stable across reporting countries. Influenza positivity was elevated in Temperate South America (predominantly A(H1N1)pdm09), Southern Africa (predominantly A(H3N2)), Eastern Africa and South-East Asia (predominantly A viruses) and part of Oceania (predominantly A(H1N1)pdm09).

 

SARS-CoV-2

• Globally, positivity continued to remain low across reporting countries except for a few countries in Central America, South-West Europe and Western Asia where positivity was elevated.

WHO encourages countries, especially those that have received the multiplex influenza and SARS-CoV-2 reagent kits from GISRS, to conduct integrated surveillance of influenza and SARS-CoV-2 and report epidemiological and laboratory information in a timely manner to established regional and global platforms. The guidance can be found here https://www.who.int/publications/i/item/WHO-2019-nCoV-integrated_sentinel_surveillance-2022.1.
 

Starting with report #501, the Global Respiratory Virus Activity Weekly Update included data from sentinel surveillance and other types of systematically conducted virologic surveillance. Countries, areas, and territories use a variety of approaches to monitor respiratory virus activity and data in this report may vary from surveillance reports posted elsewhere. Analyses stratified by source of surveillance is available through Respimart.