Respiratory Viruses Surveillance Bulletin: Epidemiological Week 37, 2026

Overview

• Regional influenza positivity increased from 14% in week 35 to 16% in week 37 of 2026. SARS-CoV-2 positivity remained at 2% from weeks 35 to 37 (Figure 1).
• The predominant circulating influenza subtype is influenza A(H3), which now accounts for 48.4% of all detections, followed by influenza A(H1N1)pdm09 (26.7%) and influenza B(Victoria) (23.8%) (Figure 2).
• Influenza activity has increased in all transmission zones, except in Oceania, Melanesia and Polynesia.  In the Eastern Asia transmission zone, activity continued to increase in all countries and areas, except Mongolia, where influenza positivity has been 0% since May 2026. In the South-East Asia transmission zone, activity increased in most countries, except Malaysia, Philippines and Viet Nam. Influenza activity in Oceania, Melanesia and Polynesia has decreased during the reporting period, after several weeks of increase.