Influenza Update N° 529

Overview

^{Published 4 June 2025 | For reporting Week 21, ending 25 May 2025}

Influenza

• In the Southern hemisphere, influenza activity remained stable in most countries with increases reported in a few countries in Temperate South America and Eastern Africa. Influenza positivity was elevated (>10%) in Tropical and Temperate South America (predominantly A(H1N1)pdm09), Southern Africa (predominantly A(H3N2)), Eastern Africa (predominantly A(H1N1)pdm09) and South-East Asia (predominantly A(H3N2)).
• In the Northern hemisphere, influenza activity continued to decline or remained stable in most countries with increases reported in a few countries in Central America and the Caribbean and single countries in Tropical South America and Western Asia. Influenza positivity remained elevated in Central America and the Caribbean (predominantly A(H1N1)pdm09), Western, Southern and South-East Asia (A(H1N1), A(H3N2) and B viruses cocirculating in similar proportions).

 

SARS-CoV-2

• Globally, SARS-CoV-2 positivity remained stable and low across the majority of reporting countries. Positivity was elevated in North America, Central America and the Caribbean, Western, Southern and South-East Asia. Minor increases in activity were reported in a few countries in Central America and the Caribbean, Tropical South America, Middle Africa and South-East Asia.

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.