2025-12-11-世界卫生组织-Wastewater_and_Environmental_Surveillance_summary_for_hepatitis_A_and_E_viruses_18页_562kb

Summary for Hepatitis A and E Viruses

Wastewater and Environmental Surveillance (WES) Overview

• Public Health Significance: Hepatitis A (HAV) and E (HEV) viruses are of intermediate public health significance, causing outbreaks but with limited pandemic potential. Both are vaccine-preventable, however vaccines are often targeted to high-risk groups or during outbreaks.
• WES Technical Feasibility：
  • Strength: Proven through multiple global pilot studies; technical and operational success has been demonstrated.
  • Testing: Early warning of 1-3 weeks before clinical detection; correlations improve with higher viral loads.
  • Limitations: Routinely useful examples for WES are limited; zoonotic HEV is confounded by animal shedding (e.g., pigs), especially genotypes 3 and 4.
• Implementation
  • Integration: WES can be integrated with existing programs for other pathogens like SARS-CoV-2 or poliovirus in both sewered (reticulated systems) and non-sewered (open drains) settings.
  • Optimal Workflow: Composite sampling (flow-weighted automatic sampling) is recommended; WES actionability should include baseline monitoring and triggers for public health actions.
  • Routine Use: Cost-effective and feasible but requires standardized methods and proven concentration.

Key WES Guidance Components

1. Key WES Criteria Categorical Assessment (CA)
CA for HAV and HEV:

CA = Categorical Assessment (High = Optimal, Intermediate = Good; Low = Needs More Work; Not Supported or Applicable)

2. Methodological Considerations and Recommendations

• Sampling： Prioritize existing WES sites, wastewater treatment plant (sewered) and environmental water (non-sewered) sampling in high-risk areas (e.g., low socioeconomic groups, endemic zones). Use composite sampling for optimal virus load representation. Choose targets based on feasibility and actionable thresholds.
• Analytical Methods: Simplified concentration methods (centrifugation, PEG precipitation) are used. Primers/probes for detection are generally available but not universally standardized. RNA quantification via RT-qPCR or RT-dPCR is common; sequencing assesses genotypes/clades. Conservatively high LoDs (around 4 log viral genome copies/L).
• Integration: WES for HAV and HEV can be added to existing multi-target surveillance programs (especially for poliovirus or SARS-CoV-2) without major infrastructure changes (low marginal cost); add primer/probes to existing assays.
• Challenges: Variable analytical and sampling methods limit high-quality comparisons; clinical WES integration is necessary for actionability but data on impacts is sparse.

Context

• The document is a supplementary summary for the broader WES Guidance document.
• More detailed methods for sampling and analysis can be found in the linked guidance.
• WES targets alongside other surveillance data can provide early warnings and complement clinical surveillance.

Sources

• WHO; Public health agencies; Select WES pilot studies

*Note: This summary highlights the wearable environmental surveillance findings and recommendations for Hepatitis A and E based on the provided text.*