流感最新消息N°539

GLOBAL INFLUENZA SURVEILLANCE AND RESPONSE SYSTEM (GISRS) RSV SARS-CoV-2 Influenza Co-circulation SUMMARY (Based on data reported to WHO for week 31, ending 03 August 2025) Globally, influenza and SARS-COV-2 activity remained low. Influenza predominated compared to SARS-CoV-2 in most areas, except in the temperateand subtropical areas of the Northern hemisphere where SARS-CoV-2 percent positivity increased in recent weeks. In tropical regions, influenza andSARS-CoV-2 activity slightly increased. In the temperate and subtropical areas of the Southern hemisphere, influenza activity continued to decrease overall,and SARS-CoV-2 remained low. A total of 72 countries reported data for influenza and 66 countries for SARS-CoV-2 for week 31. [Figures 1a, 1b, 1c and 1d] qInfluenza Globally, influenza activity remained low, with influenza A viruses continuing to predominate. Different patterns were observed across hemispheresand transmission zones. [Figure 2] In the Southern hemisphere, influenza activity decreased overall, although with different trends reported across geographical regions. Influenza activityremained elevated in Oceania and some countries in Tropical and Temperate South America, Eastern Africa and South-East Asia. Compared with theprevious week, most countries reported stable activity, with a small increase in countries in Oceania. [Figures 3 and 4] In the Northern hemisphere, over the past few weeks, influenza activity remained low and stable in most transmission zones except for Tropical SouthAmerica, Western, Middle and Eastern Africa, Southern and South-East Asia where an increasing trend was observed and percent positivity was over30% in some countries. Influenza positivity remained elevated but stable also in some countries in Central America and the Caribbean. [Figures 3 and4] Influenza A(H1N1)pdm09 predominated in the Americas, Western and Middle Africa, South West Europe and Oceania whilst influenza A(H3N2) wasthe predominant circulating virus in Eastern and Southern Africa, Northern Europe, and in Asia. Influenza B predominated in Northern Africa.[Figures 5 and 6] qSARS-CoV-2Globally, SARS-CoV-2 positivity remained stable and low overall, with a few countries reporting elevated positivity (>10%). Increases were reported in countries in Central America and the Caribbean, Western Africa, Northern and Eastern Europe, Western and Eastern Asia. [Figures 7 and 8] qRespiratory Syncytial Virus (RSV)RSV positivity remained stable and low across reporting countries, with small increases reported only in Central America and the Caribbean. Activity remained elevated in some part of Central America and the Caribbean, and Tropical and Temperate South America where positivity was over 30% ina few countries. [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 1d) Weekly numbers of influenza andSARS-CoV-2 virus specimens tested andpercent positivity in Southern hemispheretemperate and subtropical areas 1b) Weekly numbers of influenza andSARS-CoV-2 virus specimens tested andpercent positivity in Northern 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:2025-31) 4) Change in proportions of specimens that testedpositive for influenza (year-week:2025-31) 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:2025-31) SARS-CoV-2 7) Proportions of specimens that tested positive forSARS-CoV-2 (year-week:2025-31) 8) Change in proportions of specimens that testedpositive for SARS-CoV-2 (year-week:2025-31) Respiratory syncytial virus 9) Proportions of specimens that tested positive for RSV(year-week:2025-31) 10) Change in proportions of specimens that testedpositive for RSV (year-week:2025-31) 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 interpret