Global Respiratory Virus Activity: Weekly Update N° 587

Overview

In week 28 2026, influenza positivity remained below 10% and SARS-CoV-2 activity remained low globally. Influenza positivity was around 10% in the tropical areas and southern hemisphere temperate and subtropical areas. RSV positivity also remained low globally.

Influenza

Globally, influenza detections remained low in week 28 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 in single countries in Tropical South America, Southern and Eastern Africa and South-East Asia. Small increases in activity were observed in single countries in Tropical South America and South-East Asia.

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

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

SARS-CoV-2

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

Respiratory Syncytial Virus (RSV)

RSV positivity was elevated (>10%) in a few countries in Central America and the Caribbean and Tropical and Temperate South America. Percent positivity was over 30% in single countries in Eastern Africa and Southern Asia. A small increase in activity was observed in a single country in Central America. RSV and influenza activity were both elevated in a few countries in Central America and the Caribbean and Temperate South America and in a single country in 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 southern hemisphere temperate and subtropical areas, influenza-specific transmissibility was reported as below seasonal threshold (1) and low (1); transmissibility using syndromic data was low (1). In the northern hemisphere temperate and subtropical areas, influenza-specific transmissibility was reported as below seasonal threshold (10) and low (1); transmissibility using syndromic data was reported as below seasonal threshold (6). Influenza-specific transmissibility was reported as low 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.