Global Respiratory Virus Activity: Weekly Update N° 562

Overview

Globally, influenza activity decreased but remained elevated with positivity around 15% in week 3 2026. SARS-CoV-2 activity remained stable and low overall. Influenza predominated and positivity was around 15% in the northern hemisphere temperate and subtropical areas, and around 20% in the tropical areas. In the southern hemisphere temperate and subtropical areas, influenza and SARS-CoV-2 positivity were both low.

Influenza

Globally, influenza detections continued to decline. Influenza A viruses were predominant among influenza detections in week 3.

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

In the southern hemisphere, influenza activity remained low overall although elevated positivity (>10%) was reported in single countries in Tropical and Temperate South America, South-East Asia and Oceania; percent positivity was over 30% in one country in Eastern Africa. Small increases in activity were observed in two countries in Temperate South America and one country in Oceania.

In the zones with elevated positivity, influenza A(H3N2) was predominant in all zones except Tropical South America where there was codominance of influenza A(H1N1)pdm09 and A(H3N2).

SARS-CoV-2

Globally, SARS-CoV-2 positivity remained stable and low, with single countries reporting elevated positivity (>10%) in South West and Temperate South America. A small increase in activity was reported in a single country in South West Europe.

Respiratory Syncytial Virus (RSV)

Globally, SARS-CoV-2 positivity remained stable and low, with single countries reporting elevated positivity (>10%) in South West Europe and Temperate South America. A small increase in activity was reported in a single country in South West Europe. RSV and influenza activity were both elevated in single countries in Central America and the Caribbean, Northern and South West Europe, and Western 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 northern hemisphere temperate and subtropical areas, influenza-specific transmissibility was reported as moderate (2); transmissibility using syndromic data was reported as below seasonal threshold (8), low (14) and moderate (9). In tropical areas, influenza-specific transmissibility was reported as below seasonal threshold in a single country.

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.