Two more infants have been hospitalized amid an outbreak of botulism, a type of severe illness caused by botulinum toxin, federal health officials say.

As of Monday, a total of 15 infants have been reported to have “suspected or confirmed” cases of infant botulism across 12 states, the U.S. Food and Drug Administration said in an advisory published Tuesday.

The total includes two new cases from two new states, Kentucky and North Carolina, according to an update from the Centers for Disease Control and Prevention.

“For 14 cases with illness onset information available, illnesses started on dates ranging from August 9 to November 10, 2025,” the FDA said in its advisory. “All 15 infants were hospitalized.”

Of the 14 infants with age and sex information available, ages ranged from 16 days to just over 5 months, and half are female, it added.

According to the advisory, no deaths have been reported to date.

The infants who fell ill were all fed ByHeart Whole Nutrition powdered infant formula, the FDA said.

The multistate outbreak investigation is being carried out by the FDA and CDC, in collaboration with the California Department of Public Health Infant Botulism Treatment and Prevention Program and other state and local health authorities, the advisory stated.

ByHeart first announced a voluntary recall of two batches of its Whole Nutrition Infant Formula on Nov. 8, “following notification from the [FDA] of a broader ongoing investigation into a recent outbreak of infant botulism.”

On Tuesday, the company said it was expanding its earlier recall to include all batches of its ByHeart Whole Nutrition Infant Formula cans and Anywhere Pack single-serve sticks nationwide.

ByHeart said it was partnering with the FDA on the recall expansion “despite the fact that no unopened ByHeart product has tested positive for Clostridium botulinum spores or toxin.”

“The safety and well‑being of every infant who uses our formula is, and always will be, our highest priority,” ByHeart president and co-founder Mia Funt said in a statement. “This nationwide recall reflects our commitment to protecting babies and giving families clear, actionable information. Alongside this recall, we are conducting a comprehensive investigation to do our part to get the answers parents expect and deserve.”

Clostridium botulinum bacteria can appear in food and produce the botulinum toxin that can result in botulism.

Botulism is a rare but serious illness. According to the CDC, the botulinum toxin can attack the nerves, leading to difficulty breathing, muscle weakness and paralysis, visual disturbances, trouble swallowing, speech issues and even death.

Infant botulism occurs when a baby swallows Clostridium botulinum spores, which can then grow in the gut and produce the botulinum toxin, the agency states.

Symptoms of infant botulism can include poor feeding, constipation, pupils that are slow to react to light, drooping eyelids, fewer facial expressions than usual, low muscle tone or a weaker-than-normal cry.

“Seek immediate medical care if your infant has consumed ByHeart Whole Nutrition Infant Formula and has any of these symptoms,” the CDC states.

According to Tuesday’s FDA advisory, information shared by the California Department of Public Health Infant Botulism Treatment and Prevention Program shows that since Aug. 1, 2025, “84 infants nationwide have received treatment for infant botulism.”

“Notably, more than 40% (15) infants who had powdered infant formula exposure consumed ByHeart Whole Nutrition infant formula,” the advisory stated. “This information shows that ByHeart brand formula is disproportionately represented among sick infants in this outbreak, especially given that ByHeart represents an estimated 1% of all infant formula sales in the United States.”

The agency said investigations into the outbreak are ongoing, but health officials have not yet identified “other infant formula brands or shared exposures that pose a risk to infants.”

ByHeart has advised anyone with recalled ByHeart infant formula cans to stop using the product and dispose of it and to seek emergent medical care for any infant that may be exhibiting any symptoms related to infant botulism.

Parents can contact the company via email at hello@byheart.com or by phone at (833) 429-4327.