Influenza Update N° 528

Overview

^{Published 28 May 2025 | For reporting Week 20, ending 18 May 2025}

Influenza

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

 

SARS-CoV-2

• Globally, SARS-CoV-2 positivity remained stable and low across the majority of reporting countries. Positivity was elevated in a few countries in Central America and the Caribbean, Southern, South-East and Western Asia where minor increases in activity were also reported. Increases were also reported in single countries in Northern and Western Africa.

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.