Global Respiratory Virus Activity: Weekly Update N° 581

Overview

In week 22 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 22 and influenza A and B viruses were detected in similar proportions.

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

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

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

SARS-CoV-2

Globally, SARS-CoV-2 positivity remained stable and low across reporting countries, with elevated positivity (>10%) reported in a single country in South-East Asia. A small increase in activity was reported in single countries in Central America and the Caribbean, Northern and Eastern Africa.

Respiratory Syncytial Virus (RSV)

RSV positivity was elevated (>10%) in a few countries in Central America and the Caribbean, Tropical South America and Eastern Africa. Percent positivity was over 30% in single countries in Eastern Africa and Southern Asia. A small increase in activity was observed in single countries in Central America and the Caribbean and Tropical South America. 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 (1); transmissibility using syndromic data was reported as low (1). In the southern hemisphere temperate and subtropical areas, influenza-specific transmissibility was reported as moderate (1) and below seasonal threshold (1); transmissibility using syndromic data was below seasonal threshold (1). 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.