Can You Get Hepatitis A from Seafood?
Yes, you can absolutely get Hepatitis A from seafood, particularly from raw or undercooked shellfish such as oysters, mussels, and clams that have been contaminated with fecally-polluted water. 1, 2
Primary Transmission Route for Seafood-Associated Hepatitis A
While person-to-person fecal-oral transmission is the most common route of Hepatitis A spread in the United States, foodborne transmission through contaminated seafood represents a well-documented and clinically significant risk. 1, 2
Shellfish are particularly high-risk because they filter large volumes of water and can concentrate Hepatitis A virus (HAV) from sewage-contaminated or inadequately treated water sources. 1
Common-source outbreaks occur from exposure to fecally contaminated food, with uncooked foods frequently recognized as outbreak sources. 1, 2
Evidence from Documented Outbreaks
Multiple investigations have confirmed shellfish as vectors for Hepatitis A transmission:
A 1988 multistate outbreak linked to raw oysters from Panama City, Florida resulted in 61 cases across five states, with HAV antigen and nucleic acid detected in oysters from both approved and unapproved harvesting beds. 3
A 2005 multistate outbreak involving 39 persons across four states was molecularly confirmed, with 100% homology found between HAV sequences in patient sera and contaminated oysters—the first U.S. investigation to identify identical HAV strains in both patients and implicated food. 4
Surveillance studies in Spain found HAV present in 8.5% of bivalve molluscs sampled from fish markets, and Italian studies detected HAV-RNA in 20% of non-depurated mussels and 23% of market samples. 5, 6
Critical Temperature Requirements for Safety
HAV is remarkably heat-stable and environmentally persistent, requiring specific cooking parameters for inactivation:
Foods must be heated to temperatures above 185°F (85°C) for at least 1 minute to inactivate HAV. 1, 2
Experimental studies demonstrate that treatments at 60°C for 30 minutes, 80°C for 10 minutes, or even immersion at 100°C for 1 minute are insufficient to completely inactivate the virus in mussels. 7
Complete viral inactivation requires prolonged treatment at 100°C for at least 2 minutes, as the shellfish body may protect the virus from heat. 7
Cooked foods can still transmit HAV if cooking is inadequate or if food is contaminated after cooking (as occurs with infected food handlers). 1, 2
High-Risk Populations Who Should Avoid Raw Shellfish
Immunocompromised individuals and those with chronic liver diseases should avoid consumption of undercooked shellfish entirely. 1
Persons with chronic liver disease who acquire Hepatitis A are at increased risk for fulminant hepatitis. 1
The European Association for the Study of the Liver (EASL) recommends that immunocompromised patients consume shellfish only if thoroughly cooked to temperatures of at least 70°C. 1
Important Caveats
Depuration (purification) processes are inadequate: Studies show no significant difference in HAV prevalence between depurated (11.1%) and non-depurated (20%) mussels, indicating current depuration methods do not reliably eliminate viral contamination. 6
Bacterial indicators are unreliable: Conventional fecal bacterial indicators do not correlate with viral contamination, making them useless for demonstrating the presence or absence of HAV in shellfish. 5, 6
Approved harvesting areas are not foolproof: HAV has been detected in oysters from both approved and unapproved harvesting beds, indicating that current monitoring and enforcement of shellfish harvesting regulations may not adequately protect consumers. 3
Environmental persistence: HAV can remain stable in the environment for months under appropriate conditions, allowing prolonged contamination of shellfish beds. 1
Note on Hepatitis E vs. Hepatitis A
The evidence provided includes extensive discussion of Hepatitis E virus (HEV) transmission through shellfish 1, but your question specifically asks about Hepatitis A. While both can be transmitted through contaminated shellfish, they are distinct viruses with different epidemiological patterns. The recommendations above apply specifically to Hepatitis A.