Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 35 (11 September 2026)

Regional Situation: In epidemiological week 35, influenza activity in the Region of the Americas shows mixed trends. Circulation remains low in North America, while the Caribbean and Central America continue to show low-to-moderate activity, with positivity rates of 5.4% and 6%, respectively. The Andean Region shows a decreasing trend, with a positivity rate of 5.5%, dominated by influenza A. In contrast, Brazil and the Southern Cone are experiencing an increase in activity, with a positivity rate of 9.4% in EW 35, dominated by influenza B. RSV shows an increasing trend in Brazil and the Southern Cone (14.2%) and moderate activity in Central America (15.7%), while a continuous decreasing trend persists in the Andean Region (5.6%). Meanwhile, SARS-CoV-2 circulation continues to increase in the Caribbean, reaching 17.1%, and remains at moderate-to-low levels in Central America (8.7%) and low levels in North America (2.6%). Regarding other respiratory viruses, the trend continues upward in several countries, with rhinovirus the most frequently detected.