Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 28 (24 July 2026)

Regional Situation: In epidemiological week 28, North America remains at low, inter-seasonal levels, with co-dominance of influenza A and B. The Caribbean continues an upward trend, with positivity at 8.8%, dominated by influenza A. Central America shows an increasing trend, with positivity at 12.4%, dominated by influenza A. The Andean subregion shows a decrease, with positivity at 6.9%. The Brazil and the Southern Cone subregion reports moderate positivity at 12.4%, with co-circulation of influenza A and B. Several countries remain at elevated levels, including Argentina (22.2%), Chile (24.4%) and Uruguay (24%), all declining from previous weeks. RSV positivity continues to rise in Central America (18.8%) and in Brazil and the Southern Cone subregion (13.4%), with a slight increase in the Andean subregion (11.8%) after previous declines. SARS-CoV-2 positivity is increasing in North America, particularly Mexico (19%), while continuing a downward trend in the Caribbean (7.9%). Syndromic surveillance shows declining ILI and SARI trends in North America, the Andean subregion and Central America, but rising ILI and SARI activity in Brazil and the Southern Cone, linked to higher influenza and RSV positivity among sampled patients.