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Volume 32, Supplement –Summer 2026

SUPPLEMENT ISSUE
Supplement

Early-Season Detection of Influenza A(H3N2) Subclade K in Wastewater, Colorado, USA, 2025–2026

Molly C. Hetherington-Rauth, Van Nguyen, Emily Washeleski, Kevin Castro Vital, Gabrielle Lequia, Deborah Aragon, Nisha B. Alden, Kirsten Weisbeck, Laura Bankers, Alexandria Rossheim, Allison Wheeler, and Shannon R. MatzingerComments to Author 
Author affiliation: Colorado Department of Public Health and Environment, Denver, Colorado, USA

Main Article

Figure 1

Comparison of hospitalizations, clinical specimens sequenced, and wastewater detection in study of early-season detection of influenza A(H3N2) subclade K in wastewater, Colorado, USA, 2025–2026. A) Influenza hospitalizations of influenza A and influenza B case-patients, by collection week. B) Clinical specimens sequenced and grouped by subclade characterization, by collection week. C) Unique wastewater utility sites at which concentrations of influenza A were above the limit of quantification, by collection week. No sites had concentrations above the limit of quantification for the weeks ending October 18 and 25, 2025. Collection week is shown by the week ending date.

Figure 1. Comparison of hospitalizations, clinical specimens sequenced, and wastewater detection in study of early-season detection of influenza A(H3N2) subclade K in wastewater, Colorado, USA, 2025–2026. A) Influenza hospitalizations of influenza A and influenza B case-patients, by collection week. B) Clinical specimens sequenced and grouped by subclade characterization, by collection week. C) Unique wastewater utility sites at which concentrations of influenza A were above the limit of quantification, by collection week. No sites had concentrations above the limit of quantification for the weeks ending October 18 and 25, 2025. Collection week is shown by the week ending date.

Main Article

Page created: June 29, 2026
Page updated: August 06, 2026
Page reviewed: August 06, 2026
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