Regional Update, Influenza and Other Respiratory Viruses. Epidemiological Week 16 (1 May 2026)

Regional Situation: In EW16, influenza activity in the Americas reflects the characteristic seasonal divergence of the transition period: North America and the Caribbean are consolidating the end of the season, with positivity rates declining toward the interseasonal baseline; Central America is completing its post-peak decline; while Brazil and the Southern Cone are entering their austral winter season with a sustained upward trend. The Andean Region presents an intermediate pattern, with an overall decline but divergent trajectories between countries. A(H3N2) is the predominant subtype in most Southern Hemisphere subregions. RSV shows opposite patterns by hemisphere: declining in North America and increasing in the Andean Region and in Brazil and the Southern Cone, consistent with the start of the austral season. SARS-CoV-2 continues its widespread decline across all subregions, remaining at low levels without signs of resurgence. SARI and ILI indicators show declines in the Northern Hemisphere, with the highest relative burden concentrated in the Southern Hemisphere during this reporting period.