US CDC declares ByHeart infant botulism outbreak over, probe continues

Feb 26 (Reuters) - The U.S. Centers for Disease Control and Prevention declared the multistate infant botulism outbreak linked to ByHeart powdered infant formula over on Thursday, while health officials continue investigating for the root cause of the contamination.

The CDC and the Food and Drug Administration said no new cases had been added since December 10 update.

The health agencies said "this outbreak is over, but activities to determine the root cause of C. botulinum in ByHeart powdered infant formula continue."

The investigation began in November 2025 after evidence tied the company's Whole Nutrition formula to infant illnesses.

As of February 26, the investigation includes 28 cases of confirmed infant botulism and 20 cases of probable infant botulism, the agencies said.

This is the first known botulism outbreak tied to infant formula anywhere in the world, according to the FDA's website.

Last month, the FDA linked the outbreak to whole-milk powder sourced from a supplier. All of New York-based ByHeart Whole Nutrition infant formula products have been recalled, the regulators said.

Infant botulism occurs when babies ingest spores of the bacteria Clostridium botulinum, which can grow in their immature digestive systems and produce the toxin.

Symptoms include constipation, poor feeding, loss of head control and difficulty in swallowing. In severe cases, infants can develop breathing problems.

The regulators added that ByHeart infant formula accounts for about 1% of all infant formula sold in the U.S., and the outbreak does not raise shortage concerns.