Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 48 (5 December 2025)

Regional Situation: Influenza activity in the Americas continues an upward trend mainly driven by activity in the Northern Hemisphere, with a positivity of 6.3%. RSV circulation remains at low levels in the last epidemiological week (EW), while SARS-CoV-2 shows a downward trend with a positivity of 6.5%. In North America, influenza and RSV activity remain at low levels and show an upward trend. SARS-CoV-2 decreases compared to the previous EW, with a positivity of 6%. In the Caribbean, influenza circulation increases, with a positivity of 12.4%. RSV activity decreases to a positivity of 19%, while SARS-CoV-2 remains at low levels with a positivity of 5%. In Central America, influenza activity increases its circulation, with a positivity of 11.4%. SARS-CoV-2 remains at low and stable levels, while RSV decreases this week with a positivity of 15.3%. In the Andean subregion, influenza A and RSV activity decrease this week to 4.9% and 3.3% positivity. SARS-CoV-2 remains stable compared to the previous EW, presenting a positivity of 5.9%. In Brazil and the Southern Cone, influenza activity remains similar to the previous EW with 12.3% 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 and with an upward trend (8% positivity). Circulation of other respiratory viruses (ORV) decreases to 3.5% at the regional level. The main viruses detected regionally correspond to rhinovirus and parainfluenza.