Global Respiratory Virus Activity: Weekly Update N° 594

Overview

In week 35 2026, globally, influenza positivity remained below 10% and SARS-CoV-2 positivity remained stable and low. Influenza positivity was at 10% in the southern hemisphere temperate and subtropical areas, and just below 10% in the tropical areas and northern hemisphere temperate and subtropical areas. RSV positivity also remained low globally.

Influenza

Globally, influenza detections remained low in week 35, with influenza A viruses detections predominant.

In the southern hemisphere, influenza percent positivity was elevated (>10%) in single countries in Tropical and Temperate South America and South-East Asia. Percent positivity was over 30% in one country in Oceania where a small increase in activity was observed.

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

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

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 South West Europe and in single countries in Northern Europe, Western, Southern and Eastern Asia. Small increases in activity were observed in countries in Central America and the Caribbean, South West Europe, and a single country in Tropical South America.

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 single countries in Central America and the Caribbean and Temperate South America. A small increase in activity was observed in a single country in Central America and the Caribbean. RSV and influenza activity were both elevated in single 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 and moderate in a single country; transmissibility using syndromic data was reported as low in a single country. In the northern hemisphere temperate and subtropical areas, influenza-specific transmissibility was reported as below seasonal threshold in twelve countries and low in a single country; transmissibility using syndromic data was reported as below seasonal threshold in seven 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.