Senior FDA official resigns in wake of 2022 infant formula shortage, acknowledges FDA communication breakdowns

FDA's Deputy Commissioner for Food Policy and Response, Frank Yiannas, has announced he is resigning from his post. His departure comes in the wake of last year's infant formula shortage, throughout which Yiannas held a prominent leadership role.

The decision also comes amid the ongoing HHS-OIG audit into whether the FDA responded adequately to the mounting crisis, as ABC News was first to report -- and whether the agency followed proper recall protocol once a deadly bacteria had been detected inside Abbott's Michigan formula plant.

Additionally, the FDA is preparing to give an update later this month on steps it plans to take to strengthen its foods program, following an independent review that found it lacks leadership and mission clarity.

An FDA spokesperson tells ABC News that "by the end of February," they will also offer additional updates on how they're improving their organizational structure -- including how Yiannas' position responsibilities will be handled moving forward.

Yiannas had been in his role since December 2018. His resignation will be effective February 24, writing in a tweet he is "honored to have served the American public, alongside each and every one of you, over these past four years."

Yiannas was among the senior officials who was involved in responding to the formula crisis and admitted to lawmakers in May 2022 that a string of internal failures and communication breakdowns at his agency contributed to how bad the situation had grown.

Lawmakers and the public alike repeatedly pushed for further clarity on why it took so long for federal regulators to respond to the mounting crisis.

Months before Abbott's massive formula recall in February of last year, there had already been warnings about quality and safety concerns at the key facility.

There had been a whistleblower report alleging a "litany of violations" and safety issues at Abbott's key plant sent to the FDA in October 2021 -- however, as Yiannas said under oath before Congress in May 2021, he and other FDA leaders didn’t learn that report for months. The agency blamed their mailroom and called it an "isolated failure" that was "likely due to COVID-19 staffing issues.”

Yiannas said the complaint was not immediately escalated, and he didn't see it until mid-February, roughly four months after it had been sent.

By that time, as ABC News has reported, reports of infants getting sick and hospitalized after consuming Abbott's formula had already been emerging, including one who had already died -- in addition to the quality and safety concerns flagged at their Sturgis facility.

However, Abbott maintains none of the bacterial strains found at their plant matched the samples genetically sequenced from the hospitalized infants, and that there is no conclusive evidence that its products contributed to the ultimate death of two infants.

"Why is it then, if you're the deputy commissioner for food policy, you didn't get the report?" Rep. Gary Palmer (R-AL) asked during the previous May hearing. "How is it that it got tied up in bureaucracy and it didn’t get to the person who arguably should be responsible for responding to it?"

"Yeah, I'm not sure why the report wasn’t shared with me and how it didn't get escalated," Yiannas said. "As you’ve heard the commissioner state, I know there's going to be a review, and we're going to try to get to the bottom of it."

Yiannas' boss, FDA Chief Robert Califf, acknowledged the response to the formula crisis had been "too slow," and that "there were decisions that were suboptimal along the way."

In his resignation letter, tendered to Califf on Wednesday, Yiannas does not own any responsibility for the agency's missteps during the formula crisis -- rather, he touts his achievements.

"In February 2022, as you rejoined the agency, I shared with you that I was considering leaving, expressing my concern that the decentralized structure of the foods program that you and I both inherited, significantly impaired FDA’s ability to operate as an integrated food team and protect the public," Yiannas' letter says.

"It was also in February of 2022 that I first learned of the infant formula incidents that had been reported to various parts of the FDA several months before, so I postponed this decision and dedicated myself and my staff to doing all we could to help tackle this crisis. With the Abbott facility now reopened, infant formula availability more prevalent, and – very importantly - the necessary monitoring, data systems, and insights now in place through the 21 Forward platform to help address the current and any future infant formula supply chain challenges, I believe the time is right for me to leave and vacate this position."

In a statement to ABC News, the FDA thanked Yiannas for his "service and dedication."

"The FDA can confirm Frank Yiannas has resigned from his position as deputy commissioner for Food Policy and Response effective February 24. The agency thanks Mr. Yiannas for his service and dedication to the FDA’s public health mission," the agency said. "Mr. Yiannas has served as a valued member of the agency’s leadership team, spearheading important initiatives including the New Era of Smarter Food Safety to help create a safer and more digital, traceable food system for our country."

ABC News' Anne Flaherty contributed to this report.