Global Respiratory Virus Activity: Weekly Update N° 602

Overview

In week 43 2026, globally, influenza positivity was below 10% and SARS-CoV-2 positivity increased slightly but remained low. Influenza positivity increased slightly but remained below 10% in the northern hemisphere temperate and subtropical areas. Influenza positivity decreased to around 5% in the southern hemisphere temperate and subtropical areas and remained around 15% in the tropical areas. RSV positivity also remained low globally.

Influenza

Globally, influenza detections remained low in week 43 with influenza A virus detections predominant.

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

In the southern hemisphere, influenza percent positivity was elevated (>10%) in some countries in Tropical South America and Oceania and in single countries in Temperate South America and Eastern Africa. Percent positivity was over 30% in a single country in South-East Asia.

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

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 South West Europe and in single countries in Central America and the Caribbean, Northern Europe, Northern Africa and Eastern Asia. Small increases in activity were observed in single countries in Northern and South West Europe.

Respiratory Syncytial Virus (RSV)

RSV positivity was elevated (>10%) in a few countries in Central America and the Caribbean and in single countries in Tropical and Temperate South America and Southern Asia. Percent positivity was over 30% in a single country in Southern Asia. Small increases in activity were observed in some countries in Central America and the Caribbean and in a single country in Tropical South America. RSV and influenza activity were both elevated in single countries in Central America and the Caribbean 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 northern hemisphere temperate and subtropical areas, influenza-specific transmissibility was reported as below seasonal threshold in 13 countries, low in four countries and moderate in a single country; transmissibility using syndromic data was reported as below seasonal threshold in seven countries and low in one country. 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.