Global Respiratory Virus Activity: Weekly Update N° 570

Overview

Globally, influenza positivity was around 10% in week 11 2026. SARS-CoV-2 activity remained low overall. Influenza predominated and positivity was around 10% in the northern hemisphere temperate and subtropical areas and in tropical areas. In the southern hemisphere temperate and subtropical areas, influenza and SARS-CoV-2 positivity were both low. Globally, RSV positivity remained stable and low.

Influenza

Globally, influenza detections continued to decline in week 11. Influenza B viruses were predominant among influenza detections.

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

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

In the zones with elevated positivity, influenza A(H3N2) was predominant in Central America and the Caribbean, Tropical and Temperate South America, Eastern Europe, Western and Southern Asia. Influenza A(H3N2) and B were codominant in North America and South-East Asia and influenza A(H1N1)pdm09 and A(H3N2) were codominant in South West and Northern Europe. Influenza B was dominant in Western Africa and Eastern Asia and influenza A(H1N1)pmd09 was dominant in Southern Africa.

SARS-CoV-2

Globally, SARS-CoV-2 positivity remained stable and low, with a single country reporting a small increase in activity and positivity above 10% in Oceania.

Respiratory Syncytial Virus (RSV)

Globally, RSV positivity remained stable and low, with a few countries reporting elevated positivity (>10%) in Eastern Africa, Europe and Western Asia. Percent positivity was over 30% in one country in Northern Africa. A small increase in activity was reported in a single country in South West Europe. RSV and influenza activity were both elevated in countries in Europe.

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 moderate (1); transmissibility using syndromic data was reported as below seasonal threshold (23), low (2) and moderate (2). Influenza-specific transmissibility was reported as below seasonal threshold in a single country in the southern hemisphere temperate and subtropical 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.