Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 37 (25 September 2026)

Regional Situation: In epidemiological week 37, respiratory virus activity in the Americas was driven mainly by RSV in Central America and the Southern Cone. Positivity was high in Panama (26.6%) and Uruguay (30.7%) and moderate-to-high in Argentina, Paraguay, Chile and Costa Rica, though trends are decreasing in most of these countries. Influenza positivity is increasing at low levels in North America and the Caribbean. It is higher in Ecuador and Argentina (17.2% each), with influenza B predominating in the Southern Cone and influenza A in the Andean Region. SARS-CoV-2 positivity is decreasing in the Caribbean, Central America, the Andean Region and Mexico, and increasing at low levels in North America overall. Barbados maintains moderate-to-high, stable activity (23.5%). ILI and SARI cases are decreasing in most subregions. The exceptions are Argentina, which reports an increase in SARI cases; Paraguay and Uruguay, which report high SARI levels; and Chile, which reports a high SARI cases, with RSV the most frequently detected virus among sampled SARI patients.