As Congress plans to address thein a hearing later this month, parents say the problem is urgent — and they want action now.
Many are going to great lengths to get their hands on formula. And, like a Washington state couple whose daughter needs formula designed for premature babies.
The 5-month-old girl, Mackenzie Jaehnert, was born three months early and spent more than 100 days in the neonatal intensive care unit. Her parents, Emily and Mac Jaehnert, say it's been a struggle to find the right formula for her, with the frustrated dad driving to at least five grocery stores in three separate counties each morning.
"You turn the corner into the baby food and formula aisle and it's just absolutely barren," Mac Jaehnert told CBS News.
The couple even has family and friends sending them cans from other states.
"Formula is the only thing that's going to get Mackenzie healthy," Emily Jaehnert said in an emotional interview.
Research firm Datasembly says 43% of formula sellers are now out of stock, up from 31% in early April.
Part of the problem is a, the leading supplier of milk formula in this country, over concerns of bacteria at its largest formula manufacturing plant, in Michigan. The recall, announced in February and later expanded, affected certain formulas of Similac, Alimentum and EleCare.
But one baby formula manufacturer is not experiencing a shortage: Pennsylvania-based ByHeart, whose product launched in March. The company says its baby formula is made with "clean" ingredients and based on the latest nutrition research.
"We worked with the world's experts in breast milk research to get closer than ever before to breast milk," said ByHeart co-founder Ron Belldegrun, who started the company with his sister, Mia Funt.
When they founded the business five years ago, they couldn't know that their product would land in the middle of a nationwide shortage. Now, their online-only sales are booming.
"I'll tell you, in just the first six days, we sold into all 50 states. That was really shocking to us," Funt said.
They're already adding another shift at their plant so they can run 24/7. Belldegrun said they're in "good shape" in part because they control their own supply chain and don't outsource production.
Abbott, meanwhile, says it's working to increase its supplies at other FDA-registered facilities. Given the shortage, the FDA is now allowing limited distribution of unaffected formulas from the company's Michigan plant.
Reckitt, the parent company behind Enfamil, did not respond to a request for comment. Gerber's parent company, Nestlé, said in a statement to CBS News, "While we are a small player in the infant formula market, we are absolutely committed to doing everything we can to help get parents and caregivers the formula they need so their babies can thrive.
"We have significantly increased the amount of our infant formula available to consumers by ramping up production and accelerating general product availability to retailers and online, as well as in hospitals for those most vulnerable."
The Centers for Disease Control and Prevention says parents should speak with their child's doctor or nurse before switching their baby's formula brand or type. And the Food and Drug Administration warns against making homemade infant formula because it could lead to serious health problems for the baby.
Editor's note: This story has been updated to correct Gerber's parent company and add their statement.
for more features.