ByHeart Botulism Outbreak May Date Back Two Years, CDC Says

An outbreak of infant botulism linked to ByHeart’s baby formula is much wider than initially thought, potentially dating back two years, U.S. health agencies said Wednesday.

An investigation found 10 new cases of baby botulism from December 2023 through July 2025, the Food and Drug Administration said. The total outbreak now includes 51 infants with confirmed or suspected botulism across 19 states that consumed formula from ByHeart, the agency said.

Although it can be fatal, there is a treatment called BabyBIG. All of the children have received the treatment, the US Centers for Disease Control and Prevention said. The California Department of Public Health holds the stockpile of the treatment and assisted the federal health agencies in the expanded investigation.

Health officials initially focused on a cluster of cases that started in August and reached a peak in November. The FDA said its investigation is ongoing. So far, no additional cases prior to December 2023 and no deaths have been reported.

ByHeart claimed to have made the “closest to breast milk” formula with organic ingredients. It expanded the recall to all of its products on Nov. 11, three days after the outbreak was first announced.

The company did not respond immediately to a request for comment.

The infant formula brand became popular during a nationwide shortage in 2022. Still, ByHeart only accounts for roughly 1% of all US infant formula sales, the FDA has said.

The agency said no formula has been found on shelves since Nov. 26, weeks after the company expanded a recall to its entire product suite. Marty Makary, head of the FDA, posted to social media recently to ask parents to report to stores if they see cans still on shelves.

Infant botulism can lead to breathing difficulties and muscle paralysis, even weeks of hospitalization, according to the CDC.