全球呼吸道病毒活动：每周更新N°555

GLOBAL INFLUENZA SURVEILLANCE AND RESPONSE SYSTEM (GISRS) Co-circulationInfluenza SUMMARY (Based on data reported to WHO for week 47, ending 23 November 2025) Globally, influenza activity was elevated with positivity over 20% in week 47.SARS-CoV-2 activity remained stable and low overall while influenzapredominated in all areas with positivity above 10% in the northern hemisphere temperate and sub-tropical zones and in the tropical zones. [Figures 1a, 1b,1c and 1d] . qInfluenza Globally, influenza activity continued to increase with influenza A viruses predominantly detected in all zones. [Figure 2] In the northern hemisphere, influenza percent positivity was elevated in countries in Central America and the Caribbean, Africa, Northern andSouth-West Europe and in Asia, with positivity over 30% in some countries in Western and Eastern Africa, Northern Europe, Western, Southern, In the southern hemisphere, influenza activity remained low overall although elevated positivity (>10%) was reported in a few countriesin Tropical and Temperate South America, Eastern and Southern Africa and Oceania; percent positivity was over 30% in a single country In the zones with elevated positivity, influenza A(H1N1)pdm09 predominated in Northern and Middle Africa whereas influenza A(H3N2) waspredominant in all other zones except Central America and the Caribbean where there was codominance of the two subtypes. [Figures 5 and 6] qSARS-CoV-2 Globally, SARS-CoV-2 positivity remained stable at low levels, with some countries reporting elevated positivity (>10%) in Central America and theCaribbean, Temperate South America, Southern Africa, Europe, and South-East Asia. Percent positivity was over 30% in a single country in South qRespiratory Syncytial Virus (RSV) RSV activity was low overall although elevated percent positivity was reported in few countries in Central America and the Caribbean, TropicalSouth America, South West Europe and Southern Asia. Compared to the previous reporting period, RSV positivity remained stable across mostcountries, with increases in activity in single countries in Central America and the Caribbean and South West Europe. [Figures 9 and 10] RSV and 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 1b) Weekly numbers of influenza andSARS-CoV-2 virus specimens tested and Influenza SARS-CoV-2 Respiratory syncytial virus 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 between 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. To assess trends, the proportion of specimens tested positive for influenza or SARS-CoV-2 was smoothed over a 3-weeks period. Thisanalysis includes only countries that tested 10 or more specimens in at least two of the three weeks. Weekly changes in the smoothedpositivity rate for each virus were calculated as absolute differences from the previous week. These absolute changes were cate- The influenza transmission zones map is based on data aggregated over a 3-weeks period, moving backward from the current weekuntil a minimum threshold of 100 tested samples is reached within each influenza transmission zone. Pie charts are displayed on Activity summaries are organized by geographical groupings of CATs.These groupings are intended solely for geographicreference and do not imply uniformity in respiratory virus transmission patterns within each group. It is important to note that Suggested citation:Global respiratory virus activity:weekly update No 555 (week 2025-47).Geneva:World HealthOrganization; 2025; Licence: CC BY-NC-SA 3.0 IGO. Disclaimer: The designations employed and the presentation of the material in this publication do not imply the expression of any opinionwhatsoever on the part of WHO concerning the legal status of any country, territory, city or area or of its authorities, or concerning The mention of specific companies or of certain manufacturers’ products does not imply that they are endorsed or recommendedby WHO in preference to others of a similar nature that are not mentioned.Errors and omissions excepted, the names of All reasonable precautions have been taken by WHO to verify the information contained in this publication.However, thepublished material is being distributed without warranty of any kind, either expressed or implied. The responsibility for the Additional surveillance