Global Respiratory Virus Activity: Weekly Update N° 592

Overview

In week 33 2026, influenza positivity was below 10% and SARS-CoV-2 activity remained low globally. During the past few weeks, influenza positivity remained just below 10% overall 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 33 with influenza A and B viruses detected in similar proportions.

In the southern hemisphere, influenza percent positivity was elevated (>10%) in one country in Temperate South America. Percent positivity was over 30% in one country in Oceania where a medium increase in activity was observed.

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 and South-East Asia and in single countries in Middle Africa, South West and Northern Europe and Eastern Asia. Percent positivity was over 30% in single countries in Tropical South America, Western and Eastern Africa and Southern Asia. Increases in activity were observed in some countries in Central America and the Caribbean and Southern Asia and in single countries in Tropical South America, Western, Eastern and Middle Africa, South West Europe and Western Asia.

In the zones with elevated positivity, influenza A(H3N2) was predominant in South West Europe, Eastern Africa, 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 Western 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 in single countries in Tropical South America, Southern and South-East Asia. Small increases in activity were observed in countries in Central America and the Caribbean, Northern Europe and in a single country in Southern Asia.

Respiratory Syncytial Virus (RSV)

RSV positivity was elevated (>10%) in a few countries in Central America and the Caribbean, Tropical and Temperate South America and in a single country in Southern Asia. Percent positivity was over 30% in a single country in Temperate South America. Small increases in activity were observed in two countries in Central America and the Caribbean. RSV and influenza activity were both elevated in single countries in 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 (1) and moderate (1); transmissibility using syndromic data was reported as moderate (1). In the northern hemisphere temperate and subtropical areas, influenza-specific transmissibility was reported as below seasonal threshold (11) and low (2); transmissibility using syndromic data was reported as below seasonal threshold (8). Influenza-specific transmissibility was reported as moderate 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.