On February 26, 2026, the FDA and CDC, in collaboration with the California Department of Public Health (CDPH), Infant Botulism Treatment and Prevention Program (IBTPP), and other state and local partners, investigated a multistate outbreak of infant botulism. Epidemiologic and laboratory analyses indicated that ByHeart Whole Nutrition infant formula is the source of this multistate outbreak of infant botulism. As of February 26, 2026, the CDC declares the outbreak over. Over recent weeks, public health officials at state and local health departments, IBTPP, and CDC reviewed the medical records of the 51 infants initially included in the investigation and applied additional criteria to characterize the cases further. Since December 10, 2025, no new cases were added, and 3 previously reported cases from 3 states were ultimately diagnosed with other illnesses and excluded from the case count. As of February 26, 2026, the investigation includes 28 cases of confirmed infant botulism and 20 cases of probable infant botulism. As of February 26, 2026, two isolates from one lot of organic whole milk powder, collected and analyzed by the FDA, have been shown by WGS analysis to match a cluster of isolates reported by the FDA on January 23, 2026. The FDA collected these two new isolates at Dairy Farmers of America, the processor for Organic West Milk, which supplies ByHeart. WGS analysis of two recently analyzed clinical isolates collected and analyzed by CDPH matches clusters of isolates from product samples. To date, WGS analysis has identified 17 different strains of this bacterium in samples from patients, finished products, and ingredients. While these sample results add to the available evidence needed to investigate the root cause of this outbreak, due to the complexities of Clostridium botulinum and limited scientific evidence currently available, the FDA has not yet determined a root cause(s). Additional sample analysis and research are being conducted to inform possible conclusions about this outbreak. The agency is now focused on post-incident response actions and activities, which may include additional surveillance, as well as prevention and compliance activities. @ https://www.fda.gov/food/outbreaks-foodborne-illness/outbreak-investigation-infant-botulism-infant-formula-november-2025?utm_medium=email&utm_source=govdelivery
