Influenza Update N° 554

Overview

Published 26 November 2025 | For reporting Week 46, ending 16 November 2025

Influenza

Globally, influenza activity continued to increase with influenza A viruses predominantly detected in all zones.

In the northern hemisphere, influenza activity remained low in most countries although increasing activity was reported in some countries. Influenza percent positivity was elevated in a few countries in Central America and the Caribbean, Northern and Middle Africa, South West and Eastern Europe and was over 30% in a few countries in Western and Eastern Africa, Northern Europe, Western, Southern and South-East and Eastern Asia. Increases in activity were observed in countries in Central America and the Caribbean, Tropical South America, Northern Africa, Europe, Southern, South-East and Eastern Asia.

In the southern hemisphere, influenza activity remained low and stable in most countries with elevated positivity (>10%) in a single country in Tropical South America and two countries in Temperate South America. Percent positivity was over 30% in single countries in Eastern Africa and South-East Asia. A small increase in activity was observed in a single country in Tropical South America.

In the zones with elevated positivity, influenza A(H1N1)pdm09 predominated in Central America and the Caribbean, Northern, Eastern and Middle Africa whereas influenza A(H3N2) was predominant in all other zones.

SARS-CoV-2

Globally, SARS-CoV-2 positivity remained stable at low levels, with some countries reporting elevated positivity (>10%) in Central America and the Caribbean, Northern and Eastern Europe and Temperate South America. Percent positivity was over 30% in one country in South West Europe. Increases in activity were reported in single countries in Central America and the Caribbean, Temperate South America, South-West and Northern Europe, and South-East Asia.

Respiratory Syncytial Virus (RSV)

RSV percent positivity remained elevated in a few countries in Central America and the Caribbean, with one country reporting positivity >30%, and single countries in Tropical South America, Western Africa and South West Europe. Compared to the previous reporting period, RSV positivity remained stable across most countries, with increases in activity in two countries in Central America and the Caribbean and one country in South West Europe. RSV and influenza activity were both elevated in three countries in Central America and the Caribbean and one country in 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.

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.