Global Respiratory Virus Activity: Weekly Update N° 567

Overview

Globally, influenza activity remained stable and positivity was above 10% in week 8 2026. SARS-CoV-2 activity remained low overall. Influenza predominated and positivity was around 15% in the northern hemisphere temperate and subtropical areas but below 10% in tropical areas. In the southern hemisphere temperate and subtropical areas, influenza and SARS-CoV-2 positivity were both low. Globally, RSV positivity remained stable and low.

Influenza

Globally, influenza detections continued to decline in week 8. Influenza A viruses were predominant among influenza detections, with a slight increase in the proportion of influenza B virus detections in recent weeks.

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

In the southern hemisphere, influenza activity remained low overall although elevated positivity (>10%) was reported in a few countries in Tropical South America and Eastern Africa and a single country in Temperate South America. No increases in activity were observed in any countries in the southern hemisphere.

In the zones with elevated positivity, influenza A(H3N2) was predominant in most of the zones except Central America and the Caribbean where influenza A(H1N1)pdm09 was dominant and Western Asia where influenza A(H1N1)pdm09 and A(H3N2) were codominant. In Western Africa and South-East Asia influenza A and B were codominant.

SARS-CoV-2

Globally, SARS-CoV-2 positivity remained stable and low, with single countries reporting elevated positivity (>10%) in Central America and the Caribbean, Northern Europe and Eastern Africa. A small increase in activity was reported in a single country in Northern Europe.

Respiratory Syncytial Virus (RSV)

Globally, RSV positivity remained stable and low, with a few countries reporting elevated positivity (>10%) in Central America and the Caribbean, Northern Africa, South West and Northern Europe and Western Asia. Small increases in activity were reported in single countries in Northern Africa, South West Europe and Central Asia and a few countries in Central America and the Caribbean, Northern and Eastern Europe.  RSV and influenza activity were both elevated in countries in Central America and the Caribbean, Northern Africa, South West and Northern Europe and Western 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 (1) and moderate (1); transmissibility using syndromic data was reported as below seasonal threshold (19), low (9) and moderate (5). Influenza-specific transmissibility was reported as below seasonal threshold in a single country in the southern hemisphere temperate and subtropical 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.