Influenza Update N° 522

Overview

^{Published 16 April 2025 | For reporting Week 14, ending 06 April 2025}

Influenza

• In the Northern hemisphere, activity continued to decline or remained stable in most countries with minor increases reported in a few countries in Central America and the Caribbean, Western Asia and Northern and Southwest Europe. Influenza positivity remained elevated (>10%) in parts of North America, Tropical South America and Central America and the Caribbean (predominantly A(H1N1)pdm09), Northern and Eastern Africa (all subtypes), Southwest, Northern and Eastern Europe (predominantly A(H3N2) and B viruses), Western and Southern (predominantly A(H3N2)), Southeast (predominantly A(H1N1)pdm09 and B) and Eastern Asia (predominantly A(H1N1)pdm09).
• In the Southern hemisphere, activity was stable or decreased in all countries except for one country in Oceania. Influenza positivity remained elevated in a few countries in Eastern Africa, and one country in Oceania (predominantly A(H1N1)pdm09).

 

SARS-CoV-2

• Globally, activity continued to be low across reporting countries except for single countries in Western Africa and Eastern Asia. Activity decreased or remained stable in all reporting countries except for few countries in Central America and the Caribbean.

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://covid.comesa.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.