Global Respiratory Virus Activity: Weekly Update N° 600

Overview

In week 41 2026, globally, influenza positivity was below 10% and SARS-CoV-2 positivity remained stable and low. Influenza positivity was below 10% in the northern hemisphere temperate and subtropical areas with a decrease in the reported specimens tested in the last three weeks. Influenza positivity was below 10% in the southern hemisphere temperate and subtropical areas and around 15% in the tropical areas. RSV positivity also remained low globally.

Influenza

Globally, influenza detections remained low in week 41 with influenza A virus detections predominant.

In the northern hemisphere, influenza percent positivity was elevated (>10%) in some countries in Central America and the Caribbean, Western Africa, Southern, South-East and Eastern Asia and a single country in Tropical South America and Northern Europe. Percent positivity was over 30% in some countries in Western, Southern and South-East Asia and in single countries in Western and Eastern Africa. Increases in activity were observed in some countries in Central America and the Caribbean, Western Africa, Western, Southern and South-East Asia and in single countries in South West Europe, Eastern Africa and Eastern Asia.

In the southern hemisphere, influenza percent positivity was elevated (>10%) in some countries in Tropical South America and in single countries in Temperate South America, Eastern Africa and Oceania. Percent positivity was over 30% in a single country in South-East Asia. A small increase in activity was reported in a single country in Tropical South America.

In the zones with elevated positivity, influenza A(H1N1)pdm09 was predominant in Northern Europe, Eastern Africa, Western, Southern and South-East Asia and Oceania and influenza A(H3N2) was predominant in Eastern Asia. Influenza B was predominant in Central America and the Caribbean, Tropical and Temperate South America and in Western Africa.

SARS-CoV-2

Globally, SARS-CoV-2 positivity remained stable and low across most reporting countries, with elevated positivity (>10%) reported in some countries in Central America and the Caribbean, Northern and South West Europe, and in single countries in Northern Africa, Western, South-East and Eastern Asia. Increases in activity were observed in two countries in Southern Asia and in single countries in Central America and the Caribbean, Northern Europe, Western, South-East and Eastern Asia.

Respiratory Syncytial Virus (RSV)

RSV positivity was elevated (>10%) in a few countries in Central America and the Caribbean and Temperate South America and in single countries in Western Africa and Eastern Asia. Percent positivity was over 30% in a single country in Southern Asia. Increases in activity were observed in single countries in Central America and the Caribbean, Western and Eastern Africa and Southern Asia. RSV and influenza activity were both elevated in countries in Central America and the Caribbean, Temperate South America, Western Africa, Southern and Eastern Asia.

Severity assessment

The severity assessments here are reported from countries, areas and territories. Assessments for transmissibility can be reported based on syndromic parameters and/or influenza-specific parameters. In the northern hemisphere temperate and subtropical areas, influenza-specific transmissibility was reported as below seasonal threshold in 16 countries, low in two countries and moderate in a single country; transmissibility using syndromic data was reported as below seasonal threshold in nine countries and low in two countries. In the southern hemisphere temperate and subtropical areas, influenza-specific transmissibility was reported as below seasonal threshold in one country. Influenza-specific transmissibility was reported as below seasonal threshold in a single country in the tropical areas.

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.