CDC Investigates Multi-State Hepatitis A Outbreak Linked to Imported Frozen Clams

In the 2016 Genki Sushi outbreak in Hawaii, 292 people were sickened by Hepatitis A traced to raw frozen scallops, with roughly 25 percent requiring hospital care. The current multi-state Hepatitis A outbreak linked to imported frozen clams differs in one alarming respect: of the 37 people infected so far, 30 have been hospitalized.

As food safety advocates at Marler Clark note, "An 81 percent hospitalization rate is extraordinary for a foodborne hepatitis A outbreak." For consumers, the immediate actionable takeaway is to check freezers for La Serranita-brand concha negra (black shell) fresh frozen shell meat and dispose of it immediately.[1][4]

The Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) are actively investigating the cluster, which has affected residents in New York, Pennsylvania, Massachusetts, and Minnesota. Illness onset dates range from July 30, 2025, to June 23, 2026, with patients ranging in age from 6 to 40 years old. The long shelf life of the 16-ounce frozen packages means the contaminated product could still be in residential or commercial freezers, posing an ongoing threat.[1][2][3][4]

Traceback data has pointed investigators toward the La Serranita-brand clams imported from Ecuador. The FDA issued a safety alert advising restaurants, retailers, and consumers not to serve or eat the product, and dealers in New York and New Jersey have initiated recalls. However, the FDA notes the clams were distributed to at least six states—including Connecticut and Ohio—and potentially further through secondary distribution networks.[3]

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Epidemiological interviews revealed a strong common denominator among the victims. According to the CDC, 77 percent of interviewed patients reported eating ceviche—raw fish or shellfish marinated in citrus juice—and 47 percent specifically recalled consuming raw or undercooked conchas negras in the 15 to 50 days before falling ill.

These figures significantly exceed the baseline consumption rates for raw shellfish in the general population, cementing the link to the imported clams. The CDC cautions that "the true number of sick people in this outbreak is likely higher than the number reported," as some individuals recover without medical care.[1][3]

Hepatitis A is a highly contagious liver infection, with symptoms including jaundice, fatigue, nausea, and abdominal pain typically appearing two to seven weeks after exposure. Because the virus has a long incubation period, recent infections may not yet be reported to health authorities. Furthermore, the 14-day window for post-exposure prophylaxis—which can prevent the infection if administered shortly after consuming contaminated food—has passed for anyone exposed before late August 2026.[1][4]

Legal and food safety advocates emphasize that the true number of illnesses is likely higher than the 37 confirmed cases. Some individuals recover without seeking medical care or are not tested specifically for the Hepatitis A virus. The timeline of the outbreak also shows a significant gap, with a long run of illnesses through February 2026, a pause, and then five more illnesses in May and June 2026.[1][3]

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The delay between the first illness in July 2025 and the FDA's initial safety alert in April 2026 has drawn scrutiny from food safety experts. Because Hepatitis A can be prevented if a vaccine or immune globulin is administered within 14 days of exposure, timely public alerts are critical. By the time the recall was initiated, the window for preventative treatment had closed for the majority of the victims.

The investigation remains open as the CDC and FDA work to identify whether additional sources or distribution networks are involved. Until the traceback is complete, public health officials urge consumers and restaurant operators to strictly adhere to the recall notice. Anyone who develops symptoms of Hepatitis A after consuming raw or undercooked clams is advised to seek medical attention immediately.[1][4]