In January 2024, public health officials in California and the US Food and Drug Administration investigated two concurrent norovirus outbreaks associated with raw oysters. Outbreak 1 consisted of individuals who consumed raw oysters from food service facilities in San Diego County. Additional illness reports came from multiple jurisdictions that included Los Angeles County and other areas in Southern California. In total, approximately 400 people across 8 local health jurisdictions reported gastrointestinal illness after raw oyster consumption. A multiagency investigation confirmed that outbreaks 1 and 2 were unrelated and implicated oysters traced to two separate, nonoverlapping harvest regions in Mexico.

A total of 179 outbreak-associated cases, including 24 laboratory-confirmed cases, were identified. Patient samples from both outbreaks identified norovirus genogroups I and II; other enteric viruses (sapovirus, astrovirus, rotavirus, and adenovirus) were also identified from one or both outbreaks. Noroviruses were genetically related by genotype within each outbreak but dissimilar between outbreaks.

On January 12, 2024, a recall notice of Rocky Point oysters distributed by EMG Industries, Inc. and harvested in Bahia Salina, Sonora, Mexico was posted.

On January 17, 2024, the FDA advised restaurants and retailers not to serve or sell certain oysters from Baja California, Mexico potentially contaminated with norovirus. The oysters were from Acuacultura Integral De Baja California SA de CV - MX 4 SS from harvest area Laguna Manuela, B.C., Mexico harvested on 12/15/2023, 12/16/2023, or 12/23/2023 or Laguna De Guerrero Negro, B.C., Mexico, harvested on 12/15/2023, 12/16/2023, 12/19/2023, or 12/29/2023.