Influenza Update N° 527

Overview

^{Published 21 May 2025 | For reporting Week 19, ending 11 May 2025}

Influenza

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

 

SARS-CoV-2

• Globally, SARS-CoV-2 positivity continued to remain low across reporting countries except for a few countries in Central America and the Caribbean and Western and South-East 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.