ByHeart Baby Formula Linked To Nationwide Botulism Outbreak

Federal health officials are confronting a rare and alarming outbreak of infant botulism linked to ByHeart Whole Nutrition infant formula, just as the nation’s vaccine policies for newborns are undergoing significant changes. The Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) have spent the past month grappling with a public health crisis that has already affected dozens of families across the United States, even as new guidance around hepatitis B vaccination for infants is set to take effect.

As of December 11, 2025, at least 51 infants across 19 states have been hospitalized with suspected or confirmed cases of infant botulism, all tied to the consumption of ByHeart Whole Nutrition infant formula, according to the FDA and CDC. The outbreak, first flagged by California health officials on November 7, has since grown in both scope and urgency. The CDC’s most recent update, released December 10, expanded the investigation’s timeline to include 10 cases dating back to December 2023, underscoring the far-reaching impact of the contaminated formula.

Botulism in infants is an exceptionally rare but life-threatening illness, typically caused when babies ingest spores of Clostridium botulinum. These spores germinate in the infant’s gut, producing a potent toxin that can cause symptoms ranging from constipation and poor feeding to muscle weakness and, in severe cases, respiratory failure. According to Dr. Jennifer Cope, chief of the CDC’s Enteric Diseases Epidemiology Branch, “While we typically expect to see 150 to 180 individual cases of infant botulism annually, an outbreak of infant botulism is unprecedented.”

Laboratory testing has confirmed the presence of botulism spores in ByHeart’s formula products, prompting federal officials to issue urgent warnings. The CDC is advising all parents and caregivers to immediately stop using any ByHeart infant formula, regardless of where it was purchased or whether it remains on sale in stores or online. The swift escalation of warnings—from specific product lots to a nationwide recall—reflects the seriousness of the threat. ByHeart, for its part, announced a voluntary recall of its formula products last month, a move that extended to both domestic and international markets.

The company’s formula had been distributed widely, both online and in brick-and-mortar stores, since at least March 2022. This broad distribution network has complicated efforts to track down and remove all affected products. According to Effingham Radio, federal health officials believe the contamination may have been present in batches dating back over three years. The CDC’s ongoing investigation includes comprehensive testing of formula containers collected from affected homes and clinical samples from infants. “CDC laboratories continue to test clinical samples from infants and formula containers collected from affected homes as the investigation remains ongoing,” the agency noted.

For families whose infants have fallen ill, the situation is dire and deeply distressing. All 51 infants identified in the outbreak have required hospitalization and were treated with BabyBIG®, the only FDA-approved antitoxin for infant botulism. While, thankfully, no deaths have been reported, the road to recovery from botulism can be long and arduous. Families are now seeking accountability, with lawsuits being filed against ByHeart by those whose children became sick after consuming the contaminated formula, as reported by Effingham Radio.

The outbreak has prompted a rapid and coordinated response from public health agencies, reflecting the unusual nature of the threat. Infant botulism is generally sporadic, with cases scattered across the country each year. A clustered outbreak tied to a single product, however, is virtually unheard of in the United States. The CDC’s investigation was triggered after an unusual spike in cases was reported by California officials, leading to a nationwide search for additional cases and the identification of a common link: ByHeart Whole Nutrition infant formula.

As the investigation continues, federal officials are urging vigilance. The CDC’s guidance is unequivocal: “CDC officials continue to urge parents to stop using any ByHeart infant formula immediately, even if it is still found for sale online or in stores.” The agency has also emphasized the importance of monitoring infants for early signs of botulism, such as constipation, weak cry, difficulty feeding, and poor head control, and seeking prompt medical attention if symptoms arise. The investigation remains open, with further updates expected as more data becomes available.

The botulism outbreak is not the only major development in infant health policy this month. On December 5, the CDC’s Advisory Committee on Immunization Practices (ACIP) voted to change long-standing guidance around hepatitis B vaccination for newborns. The new recommendation allows for what the committee calls “shared clinical decision-making” for infants born to mothers who test negative for hepatitis B. This means that, rather than an automatic birth dose, parents and healthcare providers can now jointly assess the risks and benefits before deciding whether and when to begin the vaccine series.

Under the revised guidance, infants whose mothers are hepatitis B negative may defer the first dose of the vaccine until two months of age. The committee urged parents and clinicians to consider household exposure risks, such as contact with individuals who have hepatitis B or who emigrated from regions with higher infection rates. The ACIP also recommended that parents discuss with healthcare providers whether to test their child’s antibody levels to determine the need for additional hepatitis B doses, using serology to assess protection.

The recommendation maintains insurance coverage for the hepatitis B vaccine across all major payment systems, including Medicaid, the Children’s Health Insurance Program, Medicare, and the federal Vaccines for Children Program. Earlier this fall, the committee also voted to recommend hepatitis B testing for all pregnant women, a move that is already covered by insurance. The changes were informed by presentations reviewing hepatitis B disease trends, vaccine safety data, and international immunization practices. Notably, the United States has long been an outlier among countries with low hepatitis B prevalence in recommending a universal birth dose.

Jim O’Neill, deputy secretary of Health and Human Services and acting CDC director, praised the committee’s approach: “The American people have benefited from the committee’s well-informed, rigorous discussion about the appropriateness of a vaccination in the first few hours of life.” The new recommendation will take effect once it is formally adopted by the CDC director.

Taken together, these developments mark a pivotal moment in federal public health policy, as agencies balance evolving vaccine guidance with emergency actions in response to an unprecedented outbreak. For families and healthcare providers alike, the past month has underscored the importance of vigilance, transparency, and adaptability when it comes to protecting the nation’s youngest and most vulnerable patients.

As the investigation into the ByHeart formula outbreak continues and the new hepatitis B vaccine guidance takes hold, parents are being urged to stay informed, consult with their healthcare providers, and report any concerns promptly. The coming months will be critical in determining the full impact of these changes—and in restoring confidence in the safety of infant nutrition and immunization in the United States.