Global Respiratory Virus Activity: Weekly Update N° 582

Overview

In week 23 2026, influenza positivity remained below 10% and SARS-CoV-2 activity remained low globally. Influenza positivity was around 10% in the southern hemisphere temperate and subtropical areas. RSV positivity also remained low globally. Please be aware that due to a transition of the data management system, data reporting is paused for three consecutive weeks (weeks 21 to 23) in the European region.

Influenza

Globally, influenza detections remained low in week 23 and influenza B viruses were predominant among influenza detections.

In the southern hemisphere, influenza percent positivity was elevated (>10%) in some countries in Temperate South America and Eastern Africa and in single countries in Tropical South America, Southern Africa and South-East Asia. Percent positivity was over 30% in a single country in Temperate South America. Small increases in activity were observed in two countries in Eastern Africa and in a single country in Temperate South America.

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

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

SARS-CoV-2

Globally, SARS-CoV-2 positivity remained stable and low across reporting countries, with elevated positivity (>10%) reported in single countries in Central America and the Caribbean, Tropical South America, Western and South-East Asia. Increases in activity were reported in two countries in Central America and the Caribbean and a single country in Tropical South America.

Respiratory Syncytial Virus (RSV)

RSV positivity was elevated (>10%) in a few countries in Central America and the Caribbean and Tropical South America. Percent positivity was over 30% in single countries in Eastern Africa and Southern Asia. Small 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 single countries in Central America and the Caribbean, Eastern Africa and Southern 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 low in one country. In the southern hemisphere temperate and subtropical areas, both influenza-specific transmissibility and transmissibility using syndromic data were reported as low in one country. Influenza-specific transmissibility was reported as below seasonal threshold in one 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.