The US Centers for Disease Control and Prevention has declared the botulism outbreak linked to ByHeart baby formula over, though federal investigations into the root cause continue.
In an update issued yesterday (26 February), the Food and Drug Administration (FDA) said no new cases have been reported since 10 December.
The probe now includes 28 confirmed and 20 probable cases, down three from the last count after misdiagnoses were excluded.
No deaths were reported in the multi-state outbreak tied to the contamination of ByHeart Whole Nutrition powdered infant formula with Clostridium botulinum (toxin), Type A.
Using whole genome sequencing, investigators have so far detected 17 different strains of the bacterium in patient samples, finished products, and ingredients.
“While these sample results add to the available evidence needed to investigate the root cause of this outbreak, due to the complexities of Clostridium botulinum and limited scientific evidence currently available, FDA has not yet determined a root cause(s),” a statement from the FDA said.
All ByHeart infant formula products remain recalled, including cans and single-serve “anywhere pack” sticks. The recall was initiated in November.
With ByHeart products representing about 1% of US infant formula sales, regulators do not expect supply shortage. The company had entered the market amid the 2022 US infant formula supply crisis.
The FDA said it aims to gain a “clearer understanding of contributing factors in this outbreak”.
It is focused on “post-incident response actions and activities, which may include additional surveillance, as well as prevention and compliance activities”.
In January, the agency linked the outbreak to a supplier to ByHeart but did not disclose the supplier’s identity.
At the time, ByHeart said it continued to “cooperate fully” with regulators.
ByHeart also said it was working with its laboratory testing partner IEH to develop new testing protocols for Clostridium botulinum and establishing an advisory board of “leading third-party experts” to validate safety measures.
Infant botulism, a rare but serious illness, occurs when Clostridium botulinum spores are ingested, colonise an infant's immature gut, and produce neurotoxins.
Symptoms include constipation, poor feeding, swallowing difficulties, and breathing issues.
The FDA has advised against using any ByHeart baby formula, irrespective of test outcomes.
“The detection of Clostridium botulinum in infant formula is complex, and a negative test result does not rule out the presence of the bacteria in the product.”
