Influenza Update N° 533

Overview

^{Published 3 July 2025 | For reporting Week 25, ending 22 June 2025}

Influenza

• Globally, influenza activity continued to decrease and was low with influenza A viruses predominant and A(H1N1)pdm09 viruses predominant among the subtyped influenza A viruses.
• In the Southern hemisphere, influenza activity remained stable with a small increase reported from a single country in Temperate South America. Influenza positivity was elevated in countries of Tropical and Temperate South America, Southern and Eastern Africa and South-East Asia.
• In the Northern hemisphere, influenza remained stable or continued to decline in most countries with increases reported from a single countries in Northern Europe and Southern Asia. Influenza positivity remained elevated in Central America and the Caribbean, Tropical South America, Western Africa, Western, Southern and South-East Asia.
• Influenza A(H1N1)pdm09 predominated in the Americas whilst influenza A(H3N2) was the predominant circulating virus in Southern and Eastern Africa, Western, Southern, Eastern and South-East Asia.

SARS-CoV-2

• Globally, SARS-CoV-2 positivity remained stable and low across the majority of reporting countries. Positivity was elevated (>10%) in a few countries in Central America and the Caribbean, Tropical South America, Western Africa, South West Europe, Western, Southern and South-East Asia. Small increases were reported in Central America and the Caribbean, Western Africa, Western and South-East Asia.

Respiratory Syncytial Virus (RSV)

• Among reporting countries, RSV positivity remained low overall, with elevated activity reported in a few countries in Central America and the Caribbean, Tropical and Temperate South America. Overall, RSV activity remained stable compared to previous weeks, except for slight increases in single countries in Central America and the Caribbean.

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 https://covid.comesa.int/publications/i/item/WHO-2019-nCoV-integrated_sentinel_surveillance-2022.1.
 

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.