Key points
CDC, public health officials in several states, the California Department of Public Health Infant Botulism Treatment and Prevention Program, and the U.S. Food and Drug Administration, are investigating a multistate outbreak of infant botulism linked to infant formula. Infant botulism happens when a baby swallows Clostridium botulinum spores that grow in the gut and make toxin. Infant botulism often starts with constipation but is usually first noticed as difficulty feeding (sucking and swallowing), a weak and altered cry, and lack of head control.
Investigation details
CDC, public health and regulatory officials in several states, the Infant Botulism Treatment and Prevention Program (IBTPP), and the U.S. Food and Drug Administration (FDA) are collecting different types of data to investigate a multistate outbreak of infant botulism.
Epidemiologic and laboratory data show that ByHeart Whole Nutrition infant formula might be contaminated with Clostridium botulinum and has made infants sick.
Epidemiologic data
Since the last update on November 26, 2025, two new cases and one new state (Virginia) have been added to this investigation. Both infants were hospitalized and treated with BabyBIG®.
As of December 3, 2025, this outbreak includes 39 infants with suspected or confirmed infant botulism from 18 states (see map). Laboratory confirmation for some cases is ongoing. Illnesses started on dates ranging from August 9 through November 19, 2025 (see timeline). All 39 infants were hospitalized and treated with BabyBIG®.
No deaths have been reported. For 38 infants with age and 39 with sex information available, they range in age from 16 to 264 days and 15 (38%) are female.
Previous updates
Epidemiologic data
Since the last update on November 20, 2025, six new cases and two new states (Massachusetts and Wisconsin) have been added to this investigation. All six infants were hospitalized and treated with BabyBIG®.
As of November 26, 2025, this outbreak includes 37 infants with suspected or confirmed infant botulism from 17 states (see map). Laboratory confirmation for some cases is ongoing. For 36 cases with illness onset information available, illnesses started on dates ranging from August 9 through November 19, 2025 (see timeline). All 37 infants were hospitalized and treated with BabyBIG®.
No deaths have been reported. For 35 infants with age and sex information available, they range in age from 16 to 264 days and 15 (43%) are female.
Laboratory data
On November 19, 2025, ByHeart reported that testing of unopened ByHeart infant formula at a third-party lab identified Clostridium botulinum in the formula.
The California Department of Public Health confirmed the presence of Clostridium botulinum type A in a culture from an opened can of ByHeart infant formula that was fed to a sick infant in this outbreak.
Additional testing of ByHeart infant formula by multiple agencies is ongoing.
Epidemiologic data
Since the last update on November 14, 2025, eight new cases and two new states (Idaho and Maine) have been added to this investigation. All eight infants were hospitalized and treated with BabyBIG®.
As of November 19, 2025, this outbreak includes 31 infants with suspected or confirmed infant botulism from 15 states (see map). Laboratory confirmation for some cases is ongoing. For 27 cases with illness onset information available, illnesses started on dates ranging from August 9 to November 13, 2025 (see timeline). All 31 infants were hospitalized and treated with BabyBIG®. No deaths have been reported. For 23 infants with age and 24 with sex information available, they range in age from 16 to 200 days and 11 (46%) are female.
Epidemiologic data
Since the last update on November 11, 2025, eight new cases and one new state (Michigan) have been added to this investigation. All 8 cases were hospitalized and treated with BabyBIG®.
As of November 14, 2025, this outbreak includes 23 infants with suspected or confirmed infant botulism from 13 states (see map). Laboratory confirmation for some cases is ongoing. For 22 cases with illness onset information available, illnesses started on dates ranging from August 9 to November 11, 2025 (see timeline). All 23 infants were hospitalized and treated with BabyBIG®. No deaths have been reported. For 22 infants with age and sex information available, they range in age from 16 to 200 days and 10 (45%) are female.
Epidemiologic data
Since the last update on November 8, 2025, two new cases from two new states have been added to this investigation: Kentucky and North Carolina. Both cases were hospitalized and treated with BabyBIG®.
As of November 10, 2025, this outbreak includes 15 infants with suspected or confirmed infant botulism from 12 states (see map). Laboratory confirmation for some cases is ongoing. For 14 cases with illness onset information available, illnesses started on dates ranging from August 9 to November 10, 2025 (see timeline). All 15 infants were hospitalized and treated with BabyBIG®. No deaths have been reported. For 14 infants with age and sex information available, they range in age from 16 to 157 days and 7 (50%) are female.
State and local public health officials are interviewing caregivers about the foods infants were fed in the month before they got sick. Fifteen infant botulism cases have been identified that were fed ByHeart Whole Nutrition powdered infant formula before getting sick.
According to information shared by IBTPP, since August 1, 2025, through November 10, 2025, 84 infants nationwide have received BabyBIG® treatment. Among them, 36 (43%) had any powdered infant formula exposure. Notably, more than 40% (15) consumed ByHeart Whole Nutrition infant formula. This information shows that ByHeart brand formula is disproportionately represented among sick infants in this outbreak, especially given FDA's data that ByHeart represents an estimated 1% of all infant formula sales in the United States. Investigations remain ongoing but have not identified any other infant formula brands or shared exposures that pose a risk to infants at this time.
Laboratory and traceback data
Officials in several states have collected leftover infant formula for testing. Preliminary laboratory results reported by the California Department of Public Health suggest the presence of the bacteria that produce botulinum toxin in an open can of ByHeart infant formula (lot 206VABP/251131P2) that was fed to an infant with infant botulism. Additional product testing by states, CDC, and FDA is ongoing with results expected in the coming weeks.
Public health actions
CDC and FDA are concerned that other lots of ByHeart Whole Nutrition infant may be contaminated and are making infants sick with infant botulism. Parents and caregivers have reported feeding infants in this outbreak different lots of ByHeart infant formula that were not included in the company's initial recall on November 8, 2025. Parents and caregivers are urged to stop using any ByHeart Whole Nutrition infant formula immediately.
Epidemiologic data
As of November 8, 2025, 13 infants with suspected or confirmed infant botulism have been reported from 10 states: Arizona, California (2), Illinois (2), Minnesota, New Jersey, Oregon, Pennsylvania, Rhode Island, Texas (2), and Washington. Laboratory confirmation for some cases is ongoing. Illnesses started on dates ranging from mid-August to November 2025. All 13 infants were hospitalized and treated with BabyBIG®. No deaths have been reported. Infants ranged in age from 16 to 157 days.
State and local public health officials are interviewing caregivers about the foods infants were fed in the month before they got sick. All 13 (100%) reported feeding ByHeart Whole Nutrition infant formula.
Laboratory and traceback data
Officials in several states have collected leftover infant formula for testing. This testing is underway, and results are not yet available but expected in the coming weeks.
Public health actions
FDA has been in contact with the firm and has recommended the firm conduct a voluntary recall due to the number of cases, severity of illness, and the strong epidemiological signal. Today, ByHeart, Inc. agreed to initiate a recall of the two lots of ByHeart Whole Nutrition infant formula (Lot: 206VABP/251261P2 and Lot: 206VABP/251131P2) that were reported to have been consumed by sick infants. FDA is continuing to work with the firm to ensure all potentially impacted products are removed from the market. FDA's investigation is ongoing to determine the point of contamination and if any additional products are impacted.