The webinar “Analysis of the 2025 Season of Respiratory Virus Circulation in the Southern Hemisphere of the Region of the Americas” brought together PAHO specialists and national experts to review the patterns, impacts, and lessons learned from the 2025 respiratory virus season in the Southern Hemisphere.
Each year, influenza and other respiratory viruses affect countries across the Americas with varying intensity. The seasonal behavior of influenza, the concurrent circulation of RSV and SARS-CoV-2, and the performance of vaccination strategies provide valuable insights to strengthen surveillance systems and immunization programs. With the peak season concluded, this session offered an important opportunity for countries to present their analyses, exchange experiences, and reflect on key findings relevant for preparedness in both hemispheres.
Regional platforms such as SARInet plus, PAHOGen, and REVELAC-i continue to play a central role in supporting timely data sharing, collaborative analyses, and cross-country learning. The content of this webinar was developed based on feedback received during the most recent SARInet/REVELAC regional meeting, ensuring alignment with country needs and priorities.
During the session, participants reviewed:
Surveillance data on respiratory viruses during the 2025 Southern Hemisphere season
Virological characterization of seasonal influenza viruses and implications for the 2026 Southern Hemisphere vaccine composition
National epidemiological updates from Brazil, Chile, and Uruguay
Preliminary findings on influenza vaccine effectiveness
Experiences from Paraguay and Panama with the introduction of RSV immunization strategies