Pan American Health Organization warns of rising influenza B in South America

The Pan American Health Organization (PAHO) issued an alert on 1 July 2026 about increased influenza activity across several Southern Hemisphere nations, notably Brazil and Chile. While influenza A (especially subtype A(H3N2)) remains dominant, recent weeks have seen a progressive rise in influenza B cases, coinciding with heightened circulation of respiratory syncytial virus (RSV) and other respiratory pathogens.

PAHO cautioned that the co‑circulation of these viruses could boost outpatient visits, hospital admissions, and demand for pediatric and intensive‑care beds, placing additional strain on health services. The organization urged member states to strengthen epidemiological and virological surveillance, ensure vaccine availability, and prioritize vaccination for high‑risk groups such as older adults, young children, people with chronic conditions, and health‑care workers. It also recommended standard preventive measures like hand hygiene, ventilation, and mask use for symptomatic individuals.

Globally, seasonal influenza causes 3‑5 million severe cases and up to 650 000 deaths each year; in the Americas the disease accounts for roughly 772 000 hospitalisations and 41 000‑72 000 deaths annually. SARS‑CoV‑2 circulation remains low and stable in the region.