The Pan American Health Organization (PAHO/WHO) has issued a warning over increasing influenza activity across several countries in the Southern Hemisphere, as the region enters the respiratory virus season. Health authorities are urging stronger surveillance, expanded vaccination coverage, and improved preparedness to manage rising demand on health systems.
PAHO reports that influenza is circulating alongside other respiratory viruses, including respiratory syncytial virus (RSV), creating a potential for increased pressure on hospitals, outpatient services, and intensive care units. Children under five years of age and older adults are identified as the most vulnerable groups during this seasonal surge.
While influenza A—particularly the A(H3N2) subtype—continues to dominate circulation, a noticeable rise in influenza B cases has been observed in parts of the Southern Cone, including countries such as Brazil and Chile. Although current data does not indicate unusually severe disease, the co-circulation of multiple respiratory viruses is expected to increase healthcare demand in the coming weeks.
PAHO highlights that seasonal influenza remains a major global health concern, causing millions of severe infections and hundreds of thousands of deaths each year. In the Americas alone, influenza is responsible for hundreds of thousands of hospitalizations and tens of thousands of deaths annually, underscoring the importance of preventive measures.
In response to the rising trend, PAHO is calling on countries to strengthen epidemiological and virological surveillance systems for influenza, RSV, and other respiratory viruses. Health systems are also encouraged to ensure adequate hospital capacity, particularly in pediatric and intensive care services, to manage potential surges in cases.
Vaccination remains the central public health recommendation, especially for high-risk groups such as older adults, young children, people with chronic illnesses, and health care workers. PAHO emphasizes that immunization is the most effective tool for preventing severe illness and reducing strain on health systems.
Alongside vaccination, the organization also recommends basic preventive measures such as hand hygiene, improved indoor ventilation, and mask use when experiencing respiratory symptoms or in high-risk environments. These combined strategies are aimed at reducing transmission and protecting vulnerable populations during the peak respiratory virus season.
