全球呼吸道病毒活动：每周更新 No.570

GLOBAL INFLUENZA SURVEILLANCE AND RESPONSE SYSTEM (GISRS) Co-circulationInfluenza SUMMARY Globally, influenza positivity was around 10% in week 11 2026. SARS-CoV-2 activity remained low overall. Influenza predominated and positivity wasaround 10% in the northern hemisphere temperate and subtropical areas and in tropical areas. In the southern hemisphere temperate and subtropical areas, qInfluenza Globally, influenza detections continued to decline in week 11. Influenza B viruses were predominant among influenza detections. [Figure 2] In the northern hemisphere, influenza percent positivity was elevated (>10%) in countries in North America, Western, Southern and South-East Asia.Percent positivity was over 30% in countries in Central America and the Caribbean, Western Africa, Europe and Eastern Asia. Increases in activity In the southern hemisphere, influenza activity remained low overall although elevated positivity (>10%) was reported in single countries in TemperateSouth America, Southern and Eastern Africa and South-East Asia. Percent positivity was over 30% in one country in Tropical South America. A In the zones with elevated positivity, influenza A(H3N2) was predominant in Central America and the Caribbean, Tropical and Temperate SouthAmerica, Eastern Europe, Western and Southern Asia. Influenza A(H3N2) and B were codominant in North America and South-East Asia andinfluenza A(H1N1)pdm09 and A(H3N2) were codominant in South West and Northern Europe. Influenza B was dominant in Western Africa and qSARS-CoV-2 Globally, SARS-CoV-2 positivity remained stable and low, with a single country reporting a small increase in activity and positivity above 10% in qRespiratory Syncytial Virus (RSV) Globally, RSV positivity remained stable and low, with a few countries reporting elevated positivity (>10%) in Eastern Africa, Europe and WesternAsia. Percent positivity was over 30% in one country in Northern Africa. A small increase in activity was reported in a single country in South West qSeverity assessment The severity assessments here are reported from countries, areas and territories. Assessments for transmissibility can be reported based on syndromicparameters and/or influenza-specific parameters. In the northern hemisphere temperate and subtropical areas, influenza-specific transmissibilitywas reported as moderate (1); transmissibility using syndromic data was reported as below seasonal threshold (23), low (2) and moderate (2). Co-circulation of influenza and SARS-CoV-2 1b) Weekly numbers of influenza andSARS-CoV-2 virus specimens tested and 1c) Weekly numbers of influenza andSARS-CoV-2 virus specimens tested and Influenza SARS-CoV-2 Respiratory syncytial virus Severity assessment Additional information Data and methods The data presented in this report originates from virologic surveillance conducted by countries, areas, and territories (CATs) and submitted to WHO FluNet through participation orcollaboration with the Global Influenza Surveillance and Response System (GISRS). These CATs employ diverse methodologies to monitor respiratory virus activity, which may resultin variations between this report and other surveillance summaries published elsewhere. To assess trends, the proportion of specimens tested positive for influenza or SARS-CoV-2 was smoothed over a 3-weeks period. This analysis includes only countries that tested 10 ormore specimens in at least two of the three weeks. Weekly changes in the smoothed positivity rate for each virus were calculated as absolute differences from the previous week. These The influenza transmission zones map is based on data aggregated over a 3-weeks period, moving backward from the current week until a minimum threshold of 100 tested samples isreached within each influenza transmission zone. Pie charts are displayed on the map only if the total percent positivity in a influenza transmission zones map is 20% or higher. All trend analyses are based on ISO 8601 calendar week numbering. surveillance systems. Severity assessments: The severity assessments here are reported from countries, areas and territories.WHO’s Pandemic influenza severity assessment (PISA): a WHO guide to assess the severityof influenza in seasonal epidemics and pandemics, 2nd ed outlines the methods for which countries, areas and territories can derive these severity assessments. Assessments fortransmissibility can be reported based on syndromic parameters and/or influenza-specific parameters. Countries, areas and territories may not provide assessments year-round. The assessments may be revised over time if there is retrospective/delayed reporting or updating of previouslyreported data. These assessments are made in the context of historical data from the country making the assessment and thus are not comparable between countries. Assessments may The quality and consistency of influenza surveillance data are influenced by changes in health seeking behaviours, routines in