Influenza Update N° 512

Overview

^{Published 5 February 2025 | For reporting Week 4, ending 26 January 2025}

Influenza

• In the Northern hemisphere, influenza activity remained elevated in many regions, including Europe (due to seasonal influenza viruses of all subtypes), part of North America (predominantly influenza A), Central America and the Caribbean (predominantly influenza A(H3N2)), part of Tropical South America, Western Africa (predominantly influenza B), Northern Africa (predominantly A(H3N2)), and Asia (predominantly influenza A(H1N1)pdm09). Activity increased in most parts of Europe, parts of Asia, and in one country each in Central America and the Caribbean, and Northern Africa.
• In the Southern hemisphere, elevated activity was observed in a few countries in Eastern Africa (predominantly influenza B), Melanesia (predominantly influenza A(H1N1)pdm09), and South-East Asia (predominantly A(H1N1)pdm09). Activity increased in one country in eastern Africa. In all other reporting countries, activity was similar or decreased in comparison to previous report.

SARS-CoV-2

• Elevated activity remained in some countries in South America, Eastern and Southern Africa and South Asia. Increased SARS-CoV-2 activity was noted in one country in Central America. Most countries showed stable or declining trends.

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.