Hepatitis A Outbreak Linked to Frozen Clams Sickens Dozens Across Four States

The Centers for Disease Control and Prevention (CDC) is investigating a multi-state outbreak of Hepatitis A that has sickened 37 people across Massachusetts, Minnesota, New York, and Pennsylvania. Of those infected, 30 have been hospitalized, though no deaths have been reported.

The outbreak, which began with illnesses starting as early as July 30, 2025, and continuing through June 23, 2026, is potentially linked to imported frozen clams. The CDC indicated that the true number of illnesses is likely higher than reported, as some individuals may recover without medical attention and not be tested, and recent cases may not yet be accounted for.

Epidemiological data from the CDC revealed that individuals interviewed reported a high consumption of ceviche, raw or undercooked shellfish, and raw or undercooked black clams. This suggests that contaminated clams may be the source of the illnesses. Further traceback investigations are underway to pinpoint the origin of the frozen clams.

The CDC's investigation has also referenced an FDA safety alert issued in April 2026 concerning La Serranita-branded concha negra (black shell) shell meat products from Ecuador. This product was distributed to restaurants and retailers in Connecticut, Massachusetts, New Jersey, New York, Ohio, and Pennsylvania, and may have been further distributed. The FDA advised consumers not to eat, serve, or sell these products due to potential Hepatitis A contamination. By May 2026, the FDA reiterated this warning and noted recalls in New York and New Jersey.

Hepatitis A is a highly contagious liver disease spread through the fecal-oral route, close personal contact, or consumption of contaminated food and beverages. Symptoms, which can appear two to seven weeks after exposure, include fatigue, fever, nausea, vomiting, abdominal pain, dark urine, and jaundice. While most individuals recover fully, severe cases can lead to acute liver failure, particularly in older adults or those with pre-existing liver conditions. The virus does not cause chronic infection like Hepatitis B or C.

Globally, the World Health Organization estimated 35,570 deaths from Hepatitis A in 2023. In the U.S., the CDC reported 1,648 cases in 2023, with an estimated 3,300 infections when accounting for underdiagnosis and underreporting, leading to 85 deaths.

There is no specific cure for Hepatitis A; treatment focuses on rest, hydration, and nutrition. Prevention is primarily through vaccination, recommended for children starting at one year of age and for adults at increased risk of infection. The vaccine can also be administered as post-exposure prophylaxis within two weeks of exposure for unvaccinated individuals.