Epidemiological Alert Seasonal Influenza and other respiratory viruses in the Southern Hemisphere - 1 July 2026

Considering the increase in influenza B activity observed in some countries of the Americas Region, as evidenced by recent increases in detections reported by national surveillance systems, and given that this increase occurs in the context of the onset of the respiratory virus season—characterized by increased transmission of seasonal influenza and the progressive circulation of respiratory syncytial virus (RSV)— particularly in the Southern Hemisphere, the Pan American Health Organization/World Health Organization (PAHO/WHO) urges Member States to strengthen epidemiological and virological surveillance of acute respiratory infections, review response capacity, and reinforce prevention and control strategies targeting high-risk groups. In this context, the co-circulation of influenza and RSV could lead to a significant increase in outpatient visits, hospitalizations, and the demand for pediatric and intensive care beds, placing additional pressure on health services, particularly during periods of peak viral circulation.