Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 41 (17 October 2025)

Regional Situation: Influenza activity in the Americas remains low but shows an upward trend. At the regional level, RSV circulation is declining, while SARS-CoV-2 remains stable during the latest epidemiological week (EW), reaching a positivity rate of 8.8%. In North America, influenza activity remains at interseasonal levels. RSV circulation is low and stable, while SARS-CoV-2 maintains the trend from the previous EW, with a positivity rate of 10.2%. In the Caribbean, influenza circulation continues with a positivity rate of 5.8%, predominantly subtype A(H1N1)pdm09. RSV activity increased this EW, reaching 10% positivity, while SARS-CoV-2 circulation decreased to 2.9%. In Central America, influenza activity declined to a positivity rate of 4.9%. SARS-CoV-2 remained stable this week (3.5% positivity), while RSV increased to 19.3%. In the Andean subregion, influenza A activity rose slightly to 5.8% positivity. RSV continued to increase this week (11.8% positivity), while SARS-CoV-2 increased compared to the previous week, reaching 8.5% positivity. In Brazil and the Southern Cone, influenza activity increased (5.9% positivity), mainly due to influenza A(H3N2) circulation. RSV circulation declined compared to the previous EW (2.7% positivity), while SARS-CoV-2 remained at low levels but showed an upward trend (8.5% positivity). Circulation of other respiratory viruses (ORVs) remains elevated and stable at the regional level.