Community-level surveillance
Studies have demonstrated that Influenza A RNA is reliably detectable in wastewater, while Influenza B is detectable but generally at lower concentrations. For example:
- A study of 100 samples from wastewater treatment plants in Karnataka, India found 18% positive for influenza A and 2% for influenza B, with detectable loads. (Panneerselvam, et al.)
- Another investigation demonstrated that concentrations of influenza A and B in wastewater followed trends observed in clinical laboratory data. (Boehm, et al.)
Thus, wastewater viral signals can serve as a leading indicator of influenza circulation, potentially giving public‐health authorities earlier warning of rising activity.
Integration of human and animal/zoonotic signals (One Health)
Influenza A viruses have zoonotic potential. For instance, the highly pathogenic avian influenza (HPAI) A(H5N1) outbreak among dairy cattle and poultry in the U.S. prompted wastewater surveillance; detection of H5 subtype RNA in wastewater aligned with animal outbreaks (Louis, et al.).
Wastewater signals thus might capture inputs from human excretion and from animal sources (via animal waste, farm runoff, milk processing, wild birds). This provides a broader view of influenza virus ecology and spill‐over risk.
Early‐warning and preparedness
Wastewater integrates signals from symptomatic, asymptomatic, and untested individuals, providing a more complete picture of population-level infection, therefore WBE can provide advance notice of rising transmission or unusual viral activity (e.g., a novel strain, bovine/poultry spill-over). For example, one study reported a 17-day lead time in forecasting a city‐wide outbreak of influenza via wastewater subtyping (Mercier, et al.).
Such lead time can support public-health stakeholders to ramp up diagnostics, vaccination campaigns, and communicate risks.
What are the implications of wastewater surveillance for Influenza A & B?
Vaccine and resource planning
Early signals of rising influenza viral load in wastewater can inform decisions on vaccination campaigns (timing, scale), hospital readiness (stockpiling antivirals, ICU capacity), and public messaging (e.g., encouraging immunization, hygiene).
Research and emerging pathogens
Although sequencing influenza from wastewater remains technically challenging, improving workflows may enable earlier detection of new variants and reassortments before they are widely identified in clinical settings (Mercier, et al.).
Tools like the GT Molecular GT‑Fast Prep Influenza A Library Kit for Illumina® are accelerating this progress by enabling targeted amplicon sequencing of the most important circulating subtypes (H1N1 and H3N2). By providing more sensitive and subtype‑specific genomic data directly from wastewater, these kits help generate actionable insights on flu variant dynamics and further bridge the gap between environmental surveillance and real‑time public health decision‑making.
A new frontier in public health
Although influenza tends to appear at lower concentrations in wastewater than enteric viruses, consistent detection across systems demonstrates that wastewater-based epidemiology is effective for community-level disease tracking.
Wastewater surveillance is proving that the pipes beneath our cities aren’t just carrying away waste, they’re carrying valuable health information. With continued research and integration into public health systems, keeping an eye on our sewers could soon become one of the smartest ways to stay ahead of the flu.
GT Molecular provides digital PCR assays optimized for wastewater matrices, including panels targeting Influenza A and B. These tools support routine surveillance, outbreak detection, and monitoring to help communities stay ahead of seasonal and emerging influenza activity.
GT Molecular provides digital PCR assays optimized for wastewater matrices, including panels targeting Influenza A and B. The GT Molecular Influenza A NGS Library Prep Kit provides further insights into circulating subtypes. These tools support routine surveillance, outbreak detection, and monitoring to help communities stay ahead of seasonal and emerging influenza activity.