Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 43 (1 November 2025)

Regional Situation: Influenza activity in the Americas remains at low levels but shows an upward trend. Circulation of RSV and SARS-CoV-2 continues to decline in the latest epidemiological week (EW). In North America, influenza activity remains at interseasonal levels. RSV circulation remains low, while SARS-CoV-2 decreases compared to the previous EW, with a positivity rate of 8.2%. In the Caribbean, circulation of influenza A(H1N1)pdm09 is increasing, with a positivity rate of 9%. RSV activity continues to rise, reaching a positivity rate of 16.4%, while SARS-CoV-2 maintains stable circulation levels with a 5% positivity rate. In Central America, influenza activity remains at low circulation levels, with a positivity rate of 4.8%. SARS-CoV-2 circulation decreases this week (3.2% positivity), while RSV continues its upward trend with a positivity rate of 16.6%. In the Andean subregion, influenza A activity remains low with a 4.4% positivity rate. RSV decreases this week to a 5.3% positivity rate, while SARS-CoV-2 remains stable compared to the previous EW, presenting a positivity rate of 6.7%. In Brazil and the Southern Cone, influenza activity continues to increase (8.5% positivity), with circulation mainly of influenza A(H3N2) and influenza B. RSV circulation reaches interseasonal levels, while SARS-CoV-2 is observed at low levels, with a trend toward stabilization (5.7% positivity). Circulation of other respiratory viruses (ORV) remains elevated (11.3% positivity) with a regional trend toward decline.