Global Respiratory Virus Activity: Weekly Update N° 595

Overview

In week 36 2026, globally, influenza positivity was around 10% and SARS-CoV-2 positivity remained stable and low. Influenza positivity was at 10% in the southern hemisphere temperate and subtropical areas and tropical areas. Influenza positivity increased to 10% in the northern hemisphere temperate and subtropical areas but there was also a decrease in the reported specimens tested for week 36. RSV positivity also remained low globally.

Influenza

Globally, influenza detections remained low in week 36 with influenza A viruses detections predominant.

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 Eastern Africa. Percent positivity was over 30% in one country in Oceania where a small increase in activity was observed. A small increase in activity was also reported in a single country in Temperate South America.

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

In the zones with elevated positivity, influenza A(H3N2) was predominant in Western Africa, Eastern Asia and Oceania; influenza A(H1N1)pdm09 was predominant in Eastern Africa, Western, Southern and South-East Asia and influenza B was predominant in Temperate South America. Influenza A and B were codominant in Central America and the Caribbean and 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 some countries in Central America and the Caribbean, Northern and South West Europe and Eastern Asia, and in single countries in Tropical South America and Western, Southern and Eastern Asia. Small increases in activity were observed in countries in Northern Europe, and in single countries in Tropical South America, South West Europe and Western, South-East and Eastern Asia.

Respiratory Syncytial Virus (RSV)

RSV positivity was elevated (>10%) in a few countries in Central America and the Caribbean and Temperate South America and in single countries in Western Africa and Southern Asia. Percent positivity was over 30% in a single country in Temperate South America. Increases in activity were observed in single countries in Central America and the Caribbean, Western Africa and Southern Asia. RSV and influenza activity were both elevated in countries in Temperate South America, Western 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 southern 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 in a single country. In the northern hemisphere temperate and subtropical areas, influenza-specific transmissibility was reported as below seasonal threshold in 14 countries, and low and moderate in single countries; transmissibility using syndromic data was reported as below seasonal threshold in nine countries. Influenza-specific transmissibility was reported as below seasonal threshold 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.