The U.S. is in the grips of a botulism outbreak tied to a premium infant formula brand. At least 23 babies have been affected.
All the reported cases of the paralyzing bacterial infection occurred between August and November and have been linked to powdered infant formula produced by ByHeart, according to a Food and Drug Administration report. The company voluntarily recalled all its products on November 11, and experts caution that more cases of the potentially fatal disease may surface.
“In some cases, after exposure, it may have taken up to a month for some babies to actually show symptoms,” says Randal De Souza, a pediatric infectious disease specialist at Golisano Children’s Hospital at the University of Kentucky.
On supporting science journalism
If you’re enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
The FDA and the Centers for Disease and Control and Prevention are currently investigating illnesses in babies from 13 states: Arizona, California, Illinois, Kentucky, Michigan, Minnesota, New Jersey, North Carolina, Oregon, Pennsylvania, Rhode Island, Texas and Washington State.
In an e-mail to Scientific American, ByHeart’s co-founder and president Mia Funt said the company was working with the FDA and independent experts on its product recall and ongoing investigations.
“Our number one priority is infant health. We express our deepest sympathy to the families currently impacted by the cases of infant botulism,” Funt wrote . The FDA did not immediately respond to a request for comment from Scientific American.
Here’s what to know about the outbreak and how to stay safe.
What to know about the botulism outbreak in babies
Botulism is a relatively rare but potentially severe infection caused by the soil-dwelling bacterium Clostridium botulinum. The bacterium produces toxins that damage nerves, De Souza says. According to the most recent CDC data, there were 243 lab-confirmed cases in the U.S. in 2021, and 181 of those infections were in infants. Between 5 and 10 percent of cases are fatal.
In infants, the first signs of infection are usually constipation, followed by varying degrees of paralysis. Babies might initially lose control of their facial expressions, mouth and eyes. They might also drool more, take longer to feed or have a weaker cry, De Souza says. The paralysis slowly progresses down through the body, he explains.
“The presentation tends to be a ‘floppy baby,’ which essentially means you lose head control first, then you lose limb control, and the last tends to be respiration: you lose your ability to breathe,” De Souza says.
How are infected infants diagnosed and treated?
A clinical diagnosis, using stool samples, can take up to a week, so any infant with a suspected case of botulism must be monitored closely, De Souza says.
If infants are hospitalized, they are placed on feeding tubes and may be intubated. Infections are treated with an antitoxin that binds to and neutralizes excess toxins in the body to stop the infection.
“Then it’s up to the body to essentially regenerate nerves,” De Souza says. That process can take weeks or months, and some babies may require further speech or feeding therapy. In extreme cases, they might require a breathing tube.
Infants who recover from botulism aren’t known to have permanent issues, De Souza says, but “a very young baby requiring multiple support modalities for months is not great.”
All 23 infants that were infected in the recent outbreak—almost all of whom are currently under seven months old—have been hospitalized, and no deaths have been reported.
How to stay safe
ByHeart and the FDA are alerting people not to use recently purchased ByHeart infant formula. Barbara Kowalcyk, director of the Institute for Food Safety and Nutrition Security at George Washington University, says to check any ByHeart formula parents might have stocked up.
“People have stuff in their pantries that they don’t always know about, or they may not hear about the recall,” Kowalcyk says. “The voluntary recall language can lead people to potentially believe that it’s not as big of an issue.”
She suspects that more cases of botulism will be uncovered in the coming weeks.
Is baby formula particularly susceptible to botulism?
Botulism has been detected in baby formula before. The pathogen mostly exists as a hardy spore, and while high pressure or heat at an industry level can kill them, “your typical heating, say, in your home kitchen will not,” De Souza says. Otherwise, “the spores just live forever.”
According to the Infant Botulism Treatment and Prevention Program (IBTPP), 84 infants in the U.S. have received treatment for botulism since August—and 36 of those cases have been linked to powdered infant formula exposure.
It’s unclear if C. botulinum contamination occurred at any point during the manufacturing process at ByHeart’s facilities or at stores that sold the product or in people’s homes after that process. The California Department of Public Health reported on November 8 that an already opened can of ByHeart formula tested positive for C. botulinum, and officials are now testing unopened products for the bacterium.
In an open letter to the FDA, ByHeart alluded to a wider “unprecedented spike” in national infant botulism. Representatives of IBTPP have also said that the spike in cases may be indicative of a broader trend, the Associated Press reported.
Other bacteria can also contaminate infant formula. In 2022 ByHeart recalled products because of contamination with Cronobacter sakazakii, a pathogen that can cause deadly infections in infants. In 2023 the company stopped producing formula at a Pennsylvania facility because of several safety violations, according to the FDA. ByHeart told Scientific American that the Pennsylvania facility has not produced infant formula since 2023 and is not connected with the current recall.
In 2022 and 2023 Abbott and Reckitt/Mead Johnson Nutrition, two of the country’s biggest infant formula manufacturers, were at the center of major national shortages after putting out voluntary recalls from C. sakazakii detections. ByHeart’s products make up approximately 1 percent of all infant formula sold in the U.S., according to the FDA. Kowalcyk doesn’t anticipate that ByHeart’s recall will trigger a similar shortage, but she says the incident does reflect a larger worrisome trend in food safety surveillance.
“I think, historically, there has been this tendency to say low-moisture foods aren’t a great environment for pathogens to grow in,” she says. “And with these recent outbreaks, we’re having to rethink that.”
