Global Respiratory Virus Activity: Weekly Update N° 572

Overview

Globally, influenza positivity was below 10% in week 13 2026. SARS-CoV-2 activity remained low overall. Influenza predominated and positivity was below 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. Holidays in some regions may have affected surveillance and testing practices in week 13 2026.

Influenza

Globally, influenza detections continued to decline in week 13 and influenza B viruses were predominant among influenza detections.

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

In the southern hemisphere, influenza activity remained low overall although elevated positivity (>10%) was reported in single countries in Temperate and Tropical South America, Southern Africa and South-East Asia. Percent positivity was over 30% in one country in Tropical South America. Small increases were reported in single countries in Temperate South America and 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 and Southern Asia. Influenza A(H1N1)pdm09 was predominant in Northern Europe and Southern Africa. Influenza B was dominant in North America, Western Africa, Eastern and South-East Asia.

SARS-CoV-2

Globally, SARS-CoV-2 positivity remained stable and low. A small increase was reported in one country in Central America and the Caribbean.

Respiratory Syncytial Virus (RSV)

Globally, RSV positivity remained stable and low, with a few countries reporting elevated positivity (>10%) in Tropical South America, Europe and a single country in Northern Africa. Percent positivity was over 30% in a single country in Eastern Africa. Small increases in activity were reported in a few countries in Eastern Europe and a single country in Eastern Africa. RSV and influenza activity were both elevated in a few 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 low in a single country; transmissibility using syndromic data was reported as below seasonal threshold and moderate in single countries. Influenza-specific transmissibility was reported as below seasonal threshold in a single country in the southern hemisphere temperate and subtropical areas and 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.