Respiratory Viruses Surveillance Bulletin: Epidemiological Week 39, 2026

Overview

• Regional influenza positivity decreased from 16% in week 37 to 14% in week 39 of 2026. SARS-CoV-2 positivity remained at 2% from weeks 37 to 39 (Figure 1).
• The predominant circulating influenza subtype is influenza A(H3), which now accounts for 53.2% of all detections, followed by influenza B(Victoria) (35.2%) and influenza A(H1N1)pdm09 (11.1%) (Figure 2).
• Influenza activity increased in most countries in the South-East Asia transmission zone, with a sharp increase in positivity observed in Cambodia, Indonesia and the Philippines. Influenza positivity decreased in both the Eastern Asia and the Oceania, Melanesia and Polynesia transmission zones in recent weeks; however, it remined elevated in China, Hong Kong SAR and the Republic of Korea.