Health authorities in the Americas are on high alert due to a concerning development: the simultaneous circulation of seasonal influenza and respiratory syncytial virus (RSV). This dual threat could put additional strain on hospitals and clinics during the winter months in the Northern Hemisphere. The Pan American Health Organization (PAHO) has issued an urgent alert, urging countries to take proactive measures to strengthen their health systems and protect vulnerable populations.
The alert is based on recent epidemiological data, which indicates that influenza activity has been steadily rising since October 2025, with A(H3N2) as the predominant strain. Early signs of seasonal activity have been observed in several Northern Hemisphere countries, while RSV circulation is showing a gradual upward trend. In the Americas, influenza positivity rates remain above 10% in the Northern Hemisphere, with significant increases in North and Central America and levels approaching 20% in the Caribbean, where A(H3N2) is dominant.
The situation is particularly concerning as some countries are experiencing higher activity levels than usual, measured by influenza detection and outpatient visits for influenza-like illness. This could lead to increased hospitalizations, especially among older adults and young children. However, it's important to note that no excess mortality has been observed to date, and the overall severity remains comparable to previous seasons.
Dr. Marc Rondy, PAHO Regional Adviser in Epidemiology of Epidemic- and Pandemic-Prone Diseases, emphasizes the need for urgent action. He states, 'The simultaneous circulation of influenza and RSV is a significant challenge that requires us to prioritize vaccination, which protects against severe cases that may require hospitalization, and maintain close surveillance, enabling timely action to prevent larger outbreaks and avoid hospital overcrowding.'
PAHO recommends several key actions for countries in the region:
- Strengthening integrated surveillance of influenza, RSV, SARS-CoV-2, and other respiratory viruses, reporting weekly data to FluNET and FluID for regional and global monitoring.
- Preparing and adjusting health service response plans to address potential increases in influenza and RSV cases and hospitalizations.
- Prioritizing influenza and COVID-19 vaccination for at-risk groups, including older adults, young children, pregnant people, individuals with chronic conditions, and healthcare workers.
- Implementing RSV prevention strategies, such as maternal vaccination and long-acting monoclonal antibodies for newborns and infants, in line with PAHO/WHO recommendations.
- Enhancing risk communication to promote essential preventive practices.
PAHO also provides practical advice for the public, emphasizing the importance of simple yet effective measures such as vaccination, frequent handwashing, covering the mouth when coughing or sneezing, wearing masks indoors if symptomatic, staying home when experiencing fever or respiratory symptoms, and seeking prompt medical care for severe symptoms. These actions can help protect individuals and their families, especially young children and older adults, from the impact of these viruses.
