Image courtesy of the FDA

California health officials report that the current infant botulism outbreak linked to ByHeart infant formula follows earlier cases dating back to November 2024. The California Department of Public Health documented at least six cases between November 2024 and March 2025. The current outbreak, initially thought to have started in August 2025, now includes 31 confirmed patients across 15 states.

All affected infants have been hospitalized, but no deaths have occurred. Botulism spores have been detected in unopened containers of ByHeart formula, and all sick infants had consumed the product. Between August 1 and November 19, 2025, 107 infants nationwide received BabyBIG treatment, a plasma-derived therapy exclusively provided by the California program.

ByHeart first recalled two formula lots, then expanded to a full product recall as the investigation continued. The FDA warns that some recalled formula remains on shelves. Infant botulism symptoms include constipation, poor feeding, loss of head control, swallowing difficulties, and in severe cases, respiratory problems.