Infant Botulism Outbreak Linked to ByHeart Formula Affects 51 Babies

A widespread outbreak of infant botulism linked to ByHeart baby formula has resulted in the hospitalization of 51 infants across 19 states, according to the U.S. Food and Drug Administration (FDA). This serious illness can lead to paralysis and, in severe cases, death. The FDA’s report on December 10, 2025, indicates a significant increase in cases from the previous count of 39, highlighting the severity of the situation.

The outbreak began affecting infants between August 9 and November 19, with cases reported in multiple states, including California, Texas, and Ohio. The FDA’s updated data reflects a broader definition of the outbreak, incorporating additional cases identified by the Centers for Disease Control and Prevention (CDC) and state health partners. All affected infants were hospitalized, but fortunately, no deaths have been reported.

Details of the Outbreak and Response

In response to the outbreak, the FDA has recalled all ByHeart infant formula products, which includes both cans and single-serve “anywhere pack” sticks. The agency emphasized that these products should not be available for sale in stores or online, as they have not received reports of recalled formula on shelves since November 26, 2025. Despite this, some consumers reported finding ByHeart products in stores such as Walmart and Target.

ByHeart, which captures about 1% of the U.S. infant formula market, had been distributing approximately 200,000 cans monthly. The company stated that parents and caregivers who have the formula at home should cease using it immediately and dispose of it.

California health officials confirmed that a sample from an open can of ByHeart formula, consumed by an infant who subsequently fell ill, contained the botulism-causing bacteria. Dr. Erica Pan, California’s state health officer, noted that testing involved injecting mice with the cultured bacterium to observe symptoms, which appeared rapidly in the test subjects.

Officials have not identified any other brands of infant formula or sources of exposure linked to this outbreak. ByHeart is conducting independent testing of the recalled batches and is collaborating closely with the FDA to ensure safety.

Understanding Botulism in Infants

Botulism is a rare but serious condition, usually affecting fewer than 200 infants annually in the U.S. It is caused by a bacterium that produces a toxin in the intestines. Infants are particularly susceptible due to their underdeveloped gut microbiomes, which cannot prevent the spores from germinating and producing toxins. The spores are commonly found in dust, dirt, and can also be present in contaminated honey.

Symptoms of infant botulism can take weeks to develop and may include poor feeding, loss of head control, drooping eyelids, and a flat facial expression. Affected infants may appear “floppy” and experience difficulties in swallowing or breathing. The only known treatment is BabyBIG, an intravenous medication derived from the blood plasma of immunized adults, developed by California’s Infant Botulism Treatment and Prevention Program. All affected infants in this outbreak have received the medication, which costs approximately $69,300 per vial.

Experts maintain that the current situation will not likely result in a shortage of infant formula, given that ByHeart represents a minor share of the market. This contrasts sharply with the formula crisis of late 2021 and 2022 when Abbott Nutrition’s products were linked to serious illnesses and subsequent recalls led to nationwide shortages.

In 2022, ByHeart had also faced scrutiny, recalling five batches of formula after a sample tested positive for cronobacter sakazakii. More recently, the FDA issued a warning letter to the company regarding areas requiring corrective actions.

As investigations continue, health officials urge parents to remain vigilant and prioritize safety when selecting infant formula products.