Cases jump to 23 in the botulism outbreak tied to baby formula. Here's what to know

No deaths have been reported.

“Parents and caregivers should stop using any ByHeart infant formula products immediately,” the FDA said.

ByHeart, a New York-based manufacturer of organic infant formula, has recalled all its products sold in the U.S. The company, which accounts for about 1% of the U.S. infant formula market, had been selling about 200,000 cans of the product each month.

It can take up to 30 days for symptoms of infantile botulism to develop, medical experts said.

Here’s what to know about the outbreak and infant botulism.

The outbreak begins

The outbreak has sickened babies aged about 2 weeks to about 6 months, the FDA said. All the infants were hospitalized after consuming ByHeart powdered formula.

California officials confirmed that a sample from an open can of ByHeart baby formula fed to an infant who fell ill contained the type of bacteria that can lead to illness.

ByHeart officials said they recalled their products “in close collaboration” with the FDA, despite the fact that no previously unopened product tested positive for the illness-causing bacteria. The type of bacteria that produces the toxin is widespread in the environment and could come from sources other than the formula, company officials have said.

FDA inspectors have been to the company's infant formula production plants in Allerton, Iowa; and Portland, Oregon, this week.

Families of at least two babies treated for botulism after drinking ByHeart formula sued the company this week. Lawsuits filed in federal courts allege that the formula they fed their children was defective and ByHeart was negligent in selling it. They seek financial payment for medical bills, emotional distress and other harm.

The FDA is investigating a rise in cases of infantile botulism. Since August, at least 84 babies have been treated for the disease, which represents “an increasing trend line of cases," according to Dr. Jessica Khouri, senior medical officer at California's Infant Botulism Treatment and Prevention Program.

Many of those babies consumed ByHeart formula, which Khouri called “unprecedented” for exposure to a common product in a short period of time.

The FDA said that shows that “ByHeart brand formula is disproportionately represented among sick infants in this outbreak.”

Illnesses began between Aug. 9 and Nov. 11, federal officials said. Cases were reported in Arizona, California, Illinois, Kentucky, Michigan, Minnesota, North Carolina, New Jersey, Oregon, Pennsylvania, Rhode Island, Texas and Washington.

Investigators have not identified any other infant formula brands or other sources of exposure in the outbreak, officials said.

Causes of infant botulism

Infant botulism typically affects fewer than 200 babies in the U.S. each year. As of Sept. 20, 133 cases had been reported in the U.S. according to the most recent Centers for Disease Control and Prevention records. There were 145 cases reported all of last year.

The infection is caused by a type of bacteria that produces a toxin in the large intestine. The bacterium is spread through hardy spores present in the environment that can cause serious illness, including paralysis.

Infants are particularly vulnerable to infection because their gut microbiomes are not developed enough to prevent the spores from germinating and producing the toxin. They can be sickened after exposure to the spores in dust, dirt or water or by eating contaminated honey.

Symptoms can take weeks to develop and can include poor feeding, loss of head control, drooping eyelids and a flat facial expression. Babies may feel “floppy” and can have problems swallowing or breathing.

Baby formula has previously been linked to sporadic cases of illness, but no known outbreaks of infant botulism tied to powdered formula have previously been confirmed, according to research studies.

Infant botulism treatment

The only treatment is known as BabyBIG, an IV medication made from the pooled blood plasma of adults immunized against botulism. California’s infant botulism program developed the product and is the sole source worldwide.

BabyBIG works to shorten hospital stays and decrease the severity of illness in babies with botulism. Because the infection can affect the ability to breathe, infants often need to be placed on ventilators.

All of the children in the ByHeart outbreak have received the medication, the CDC said. The treatment is delivered in vials that cost $69,300 apiece, California officials said.

Potential impact on U.S. formula supplies

There is little danger of infant formula shortages because ByHeart represents a small share of the market. That's far different from the crises in late 2021 and 2022, when four infants were sickened by a different germ after consuming formula made by Abbott Nutrition. Two of the babies died. No direct link was found between the Abbott products and the infections caused by a different germ, cronobacter sakazakii, but FDA officials closed the company's Michigan plant after contamination and other problems were detected.

Abbott recalled top brands of infant formula, triggering a nationwide shortage that lasted months.

In 2022, ByHeart recalled five batches of infant formula after a sample at the company's packaging plant tested positive for cronobacter sakazakii. In 2023, the FDA sent a warning letter to the company detailing “areas that still require corrective actions.”

Reviewing infant formula ingredients

Federal health officials have vowed to overhaul the U.S. food supply and are taking a new look at infant formula.

Health Secretary Robert F. Kennedy Jr. has directed the FDA to review the nutrients and other ingredients in infant formula, which fills the bottles of millions of American babies.

The effort, dubbed “Operation Stork Speed,” is the first deep look at the ingredients since 1998.

FDA officials are reviewing comments from industry, health experts and public to decide next steps.

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.