Botulism Outbreak Linked to ByHeart Infant Formula Affects Over 100 Babies

California health officials are reporting a significant outbreak of infant botulism linked to ByHeart infant formula, with more than 100 babies receiving treatment. The outbreak, which has affected infants in 15 states, was preceded by several cases beginning in November 2024.

As of now, 31 confirmed patients have been hospitalized, but thankfully, none have died. The California Department of Public Health, or CDPH, noted that at least six cases of infant botulism were detected between November 2024 and March 2025.

Initially, it was believed that the outbreak began in August 2025, but the CDPH spokesperson clarified that they cannot connect any pre-August 1 cases to the current outbreak. This confusion arose because, prior to the current outbreak, the number of cases was within expected trends based on previous years.

Importantly, prior to this incident, no powdered infant formula had tested positive for Clostridium botulinum in the United States. From August 1 to November 19, 2025, a total of 107 infants nationwide were treated with BabyBIG, a human plasma-derived treatment specifically for infants with botulism.

This figure includes confirmed cases and those who were treated while awaiting test results. The BabyBIG treatment is developed by the CDPH and is the only source of this critical treatment. The investigation by the CDPH, in collaboration with the Centers for Disease Control and Prevention and the Food and Drug Administration, was initiated after an increase in requests for BabyBIG treatment.

In response to the outbreak, ByHeart initially recalled two lots of its powdered infant formula, but as investigations progressed, the company expanded the recall to include all of its infant formula products.

The FDA has issued warnings to parents and caregivers, indicating that some of the recalled formula may still be available on store shelves. The infant formula has also been sold in several other countries, prompting those nations to issue alerts as well.

Symptoms of infant botulism include constipation, poor feeding, loss of head control, and difficulty swallowing, which can escalate to respiratory arrest. It is important to note that symptoms can take several weeks to develop after ingestion of the contaminated formula.

According to the CDC, all infants affected in this outbreak were fed ByHeart formula, as spores linked to botulism poisoning were found in unopened containers of the product. This outbreak raises critical public health concerns regarding food safety and the urgent need for stringent regulations in the infant nutrition sector.