The Centers for Disease Control and Prevention (CDC) has released an update on its investigation into a nationwide outbreak of infant botulism linked to ByHeart infant formula. Working with the California Department of Public Health’s Infant Botulism Treatment and Prevention Program (IBTPP), CDC investigators have expanded the outbreak timeline to include 10 cases dating back to December 2023.
As of December 10, 2025, 51 infants from 19 states have been hospitalized due to this outbreak and treated with BabyBIG, a medication used for infant botulism. No deaths have been reported so far. Infant botulism occurs when babies ingest Clostridium botulinum spores that produce toxins in the gut. Early symptoms can include constipation, difficulty feeding, weak or altered crying, and poor head control.
CDC officials are urging parents to immediately stop using any ByHeart Whole Nutrition infant formula, regardless of where it is found for sale. Laboratory testing has confirmed contamination of the formula with botulism spores capable of causing illness in infants.
The CDC described its response as an example of rapid action to protect public health. The agency was first alerted by IBTPP on November 7, 2025, after a rise in cases among infants consuming ByHeart formula—a rare occurrence since infant botulism typically appears as isolated cases rather than outbreaks. Dr. Jennifer Cope, chief of the Enteric Diseases Epidemiology Branch at CDC, stated: “While we typically expect to see 150-180 individual cases of infant botulism annually, an outbreak of infant botulism is unprecedented.” That same evening, CDC and the U.S. Food and Drug Administration contacted ByHeart to urge immediate removal of some products from the market.
On November 8, CDC issued guidance advising all parents in the United States to stop using two specific lots of ByHeart formula and notified them about the outbreak. As more data became available over subsequent days, CDC broadened its warning on November 11 to include all ByHeart infant formula products.
CDC laboratories continue testing clinical samples from affected infants as well as samples taken from open containers collected from their homes.
This marks the first recorded outbreak of infant botulism associated with contaminated formula in the United States. According to CDC officials, their expertise allowed them to respond quickly and provide clear instructions during this public health emergency: “Although this is the first ever outbreak of infant botulism, CDC experts used their rapid response skillset to act immediately to save the lives of infants in America and provide clear guidance to frightened parents during a health emergency.”
The CDC plays a central role in protecting Americans’ health by providing timely information and responding rapidly to disease threats through scientific research and collaboration with local partners across the country.
