Global Respiratory Virus Activity: Weekly Update N° 593

Overview

In week 34 2026, and during the past few weeks, both influenza and SARS-CoV-2 positivity remained stable and low globally. Influenza positivity remained below 10% overall in the southern hemisphere temperate and subtropical areas, tropical areas and northern hemisphere temperate and subtropical areas. RSV positivity also remained low globally.

Influenza

Globally, influenza detections remained low in week 34 with influenza A and B viruses detected in similar proportions.

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. A small increase in activity was also observed in one country in Tropical South America.

In the northern hemisphere, influenza percent positivity was elevated (>10%) in some countries in Central America and the Caribbean, Tropical South America, Western Africa, Western, Southern, South-East and Eastern Asia and in single countries in Middle Africa, South West and Northern Europe.

Percent positivity was over 30% in a single country in Western Africa and two countries in Southern Asia. Increases in activity were observed in some countries in Western Africa and Southern Asia and in single countries in Northern Europe and South-East Asia.

In the zones with elevated positivity, influenza A(H3N2) was predominant in Western Africa, South West Europe, 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 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 in single countries in Southern, South-East and Eastern Asia. Small increases in activity were observed in single countries in Central America and the Caribbean, South West and Northern Europe and Southern 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 Eastern Africa and Southern Asia. Percent positivity was over 30% in a single country in 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 Central America and the Caribbean, 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 low in a single country and extraordinary 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 ten countries and low in two countries; transmissibility using syndromic data was reported as below seasonal threshold in seven countries. Influenza-specific transmissibility was reported as low 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.