Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 34 (29 August 2025)

Regional Situation: Influenza activity across the Americas remains low. SARS-CoV-2 activity has shown an increase in recent epidemiological weeks (EW). At the regional level, RSV circulation is trending downward. In North America, influenza activity remains at interseasonal levels. In the Caribbean, circulation is increasing, with a positivity rate of 9.3%. Subtype A(H1N1)pdm09 continues to be the predominant strain. RSV activity remains low and stable in North America, while in the Caribbean it is decreasing, reaching a positivity rate of 6.2% in the latest EW. SARS-CoV-2 activity is increasing in North America, where positivity reached 5.8%, while in the Caribbean it is decreasing to 18.6%. In Central America, influenza activity continues to decline, with a positivity rate of 7.5%. SARS-CoV-2 activity remains steady this week, with a positivity rate of 5.8%, while RSV is rising again, reaching 15.4%. In the Andean subregion, influenza A activity continues its downward trend, with a positivity rate of 6%. RSV activity remains high, with a stable trend and a positivity rate of 10.6%, while SARS-CoV-2 circulation has slightly increased compared to the previous week, with a positivity rate of 4.4%. In Brazil and the Southern Cone, influenza activity continues to decline, with a positivity rate of 3.1%. RSV circulation has decreased compared to the previous EW, with a positivity rate of 12.9%, while SARS-CoV-2 activity remains low. Circulation of other respiratory viruses (ORVs) is elevated and trending upward in most subregions except North America. The Brazil and Southern Cone subregion stands out for the detection of Rhinovirus, Parainfluenza, and Metapneumovirus.