Global Respiratory Virus Activity: Weekly Update N° 586

Overview

In week 27 2026, influenza positivity remained below 10% and SARS-CoV-2 activity remained low globally. Influenza positivity was just above 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 27 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 and South-East Asia. Percent positivity was over 30% in some countries in Temperate South America. A small increase in activity was observed in a single country in Tropical South America.

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

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

Influenza A and B were codominant in Tropical South America.

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, Tropical South America, Northern and Middle Africa, and 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. Small increases in activity were 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, Tropical and Temperate South America, 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 southern hemisphere temperate and subtropical areas, influenza-specific transmissibility was reported as below seasonal threshold (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 (7) and low (1). 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.