Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 13 (10 April 2026)

Regional Situation: Influenza activity in the Americas continues to decrease compared to the previous epidemiological weeks. Positivity declined across most subregions, although sustained circulation persists (overall positivity 9.4%). Over the past four weeks, virus circulation in the Americas continued to be predominantly associated with influenza B (approximately 70% of the detected cases), despite a downward trend. Respiratory syncytial virus (RSV) activity remains stable, with low regional positivity (2.0%). SARS-CoV-2 activity continues to decrease with positivity remaining at low levels (3.2%) and showing a slight downward trend; no evidence of resurgence has been observed at the regional level. Circulation of other respiratory viruses (ORV) in the Americas has been increasing over the last weeks, with a rise in overall positivity (3.6%) suggesting a reactivation of transmission to be monitored, predominantly driven by rhinoviruses. Severe acute respiratory infection (SARI) and Influenza-like illness (ILI) cases in the Americas continue to decrease being that the overall burden of disease remains primarily associated with influenza, with lower contributions from RSV and SARS-CoV-2.