流感最新消息N°541

GLOBAL INFLUENZA SURVEILLANCE AND RESPONSE SYSTEM (GISRS) RSV SARS-CoV-2 Influenza Co-circulation SUMMARY (Based on data reported to WHO for week 33, ending 17 August 2025) Globally, influenza and SARS-COV-2 activity remained low. Influenza predominated in most areas, except in the temperate and subtropical areas of theNorthern hemisphere where SARS-CoV-2 percent positivity increased in recent weeks. In tropical regions and in the temperate and subtropical areas of theSouthern hemisphere, influenza activity predominated. [Figures 1a, 1b, 1c and 1d] qInfluenza Globally, influenza activity remained low, with influenza A viruses continuing to predominate. Different patterns were observed across hemispheres In the Southern hemisphere, influenza activity remained stable in most reporting countries with an increase in activity observed in a single country inOceania. Influenza positivity remained elevated (>10%) in South-East Asia and Oceania. [Figures 3 and 4] In the Northern hemisphere, over the past few weeks, influenza activity remained low and stable in most transmission zones.Influenzapositivity was elevated in Central America and the Caribbean, Western and Eastern Africa, Southern and South-East Asia and percent positivitywas over 30% in some countries. An increase in activity was observed in Tropical South America, Northern Europe and South-East Asia. [Figures 3 and 4] In the transmission zones with elevated positivity, influenza A(H1N1)pdm09 predominated in Central America and the Caribbean, Western Africa andOceania whilst influenza A(H3N2) was the predominant circulating virus in Southern Asia and South-East Asia. In Eastern Africa, influenza A and Bviruses were detected in similar proportion. [Figures 5 and 6] qSARS-CoV-2Globally, SARS-CoV-2 positivity remained at low levels but increased slightly, with a few countries reporting elevated positivity (>10%) in Central America and the Caribbean, Europe, Western, Southern and Eastern Asia with increases in activity reported in some countries in each of these zonesapart from Southern Asia. An increase in activity was also observed in a single country in Tropical South America. [Figures 7 and 8] qRespiratory Syncytial Virus (RSV)Positivity remained elevated in some countries in Central America and the Caribbean, Tropical and Temperate South America where positivity rates were over 30% in a few countries. RSV positivity remained stable and low across the majority of reporting countries, with small increases in activityreported only in Central America and the Caribbean. [Figures 9 and 10] Co-circulation of influenza and SARS-CoV-2 1a) Weekly numbers of influenza and SARS-CoV-2 virus specimens tested and percent positivity at the global level(last 12 months) 1c) Weekly numbers of influenza andSARS-CoV-2 virus specimens tested andpercent positivity in Tropical areas 1b) Weekly numbers of influenza andSARS-CoV-2 virus specimens tested andpercent positivity in Northern hemispheretemperate and subtropical areas 1d) Weekly numbers of influenza andSARS-CoV-2 virus specimens tested andpercent positivity in Southern hemispheretemperate and subtropical areas Influenza 2) Weekly numbers of influenza virus positive specimens by type and subtype and percent positivity at the globallevel (last 12 months) 3) Proportions of specimens that tested positive forinfluenza (year-week:2025-33) 4) Change in proportions of specimens that testedpositive for influenza (year-week:2025-33) 6) Weekly distribution of influenza virus types andsubtypes by geographic zone (last 12 months) 5) Proportions of influenza virus types and subtypes byinfluenza transmission zones (year-week:2025-33) SARS-CoV-2 7) Proportions of specimens that tested positive forSARS-CoV-2 (year-week:2025-33) 8) Change in proportions of specimens that testedpositive for SARS-CoV-2 (year-week:2025-33) Respiratory syncytial virus 9) Proportions of specimens that tested positive for RSV(year-week:2025-33) 10) Change in proportions of specimens that testedpositive for RSV (year-week:2025-33) Additional information Data and methods The data presented in this report originates from virologic surveillance conducted by countries, areas, and territories (CATs) andsubmitted to WHO FluNet through participation or collaboration with the Global Influenza Surveillance and Response System(GISRS). These CATs employ diverse methodologies to monitor respiratory virus activity, which may result in variations betweenthis report and other surveillance summaries published elsewhere. This report includes virologic data from bothsentinel surveillance and other systematically conducted surveillance. Dueto differences in surveillance strategies, direct comparisons of percent positivity between CATs should be interpreted with caution.The data source used for each CAT was decided jointly corresponding with WHO Regional Offices and the respective reporting entity. To assess trends, the proportion of specimens te