Hepatitis A, caused by the Hepatitis A virus (HAV), remains a public-health concern worldwide despite being vaccine-preventable and typically an acute infection (does not become chronic) (Hepatits A Surveillance Report, CDC). Traditional surveillance focuses on reported cases via clinical diagnosis, but many infections go undetected because they may be mild or asymptomatic, and vulnerable populations, may be under-represented in case reporting.
Monitoring HAV in wastewater (i.e., sewage or influent to treatment plants) offers an additional surveillance tool. By measuring viral RNA shed into the sewer system, wastewater surveillance can provide insight into community-level circulation, potentially detect outbreaks earlier, and identify geographic or socioeconomic hotspots of transmission.
Why monitor Hepatitis A in wastewater?
Broad community‐level surveillance
- HAV is excreted in feces of infected individuals, and thus viral particles (or viral RNA) can be present in wastewater influent. This makes WBE (Wastewater-Based Epidemiology) a feasible method for population-level monitoring. For example, one study found HAV RNA in raw sewage over an 8-month period in southern Italy (Morace, et al.).
Early warning and outbreak detection
- Because wastewater aggregates signal from many individuals, possibly including asymptomatic infections, detection of HAV in wastewater could precede or at least complement clinical case detection, offering earlier insight into rising circulation.
For instance:- A study during a hepatitis outbreak in Detroit found that HAV concentrations in wastewater correlated with reported case counts one week later (McCall et al.).
- A longitudinal study examining wastewater in an urban city in Argentina found that HAV concentrations in the collected samples correlated with reported clinical trends for Hepatitis A. Genetic characterization of these samples found that the Hepatitis A lineages in wastewater were the same as those found in clinical cases at given time points (Fantilli et al.)
Monitoring equality and vulnerability
- The association of wastewater HAV detection with socioeconomic vulnerability suggests the method can highlight disparities in disease burden. For example, the U.S. national study found that states with above-average rates of homelessness had ~48 % higher likelihood of HAV detection in wastewater (Zulli, et al.).
Complement to clinical surveillance
- Traditional surveillance for hepatitis A relies on reported laboratory confirmed cases (anti-HAV IgM or HAV RNA), and on providers reporting to public-health bodies (Hepatitis A Surveillance Guidance, CDC).
- Many mild or asymptomatic infections may go undetected, and people in vulnerable settings may have limited access to care and testing. Therefore, wastewater surveillance offers a complementary data stream which provides a non-biased, population-level signal, improving situational awareness.
Public health implications
- Wastewater surveillance for HAV can help identify hidden or underreported transmission, especially in populations underserved or outside routine clinical surveillance (e.g., homeless shelters, food service workers).
- Early detection via wastewater can enable timely public health interventions, such as targeted vaccination campaigns, improving hygiene/sanitation in high-risk settings, or food-safety inspections.
- By linking wastewater HAV signals to socioeconomic vulnerability data, health authorities can drive equity-focused responses (e.g., prioritizing vaccination in communities with high homelessness or overdose-death rates).
- As part of One Health/environmental health thinking, wastewater monitoring underscores that liver-infecting viruses transmitted by the fecal oral route (like HAV) leave detectable community-level signatures beyond clinical case numbers.
At GT Molecular, we translate wastewater surveillance into actionable insights, giving users the tools to detect pathogens early and respond before outbreaks escalate. Our HepA digital PCR kit helps public health teams monitor transmission proactively and protect vulnerable populations.
