After just six months at the helm of the US Food and Drug Administration’s (FDA’s) drug evaluation centre, Tracy Beth Høeg has reportedly been ousted from her position – further deepening the void at the agency left by the departure of several members of senior management.

In an interview with the New York Times, Høeg, a sports physician and epidemiologist by training, said that she was fired from the agency after she refused to resign, and that she is unaware who or where the decision came from. Høeg was the fifth person to take the helm at the Centre for Drug Evaluation and Research (CDER) since US President Donald Trump began his second term in office 15 months ago.

During her time at the FDA, Høeg played a key role in altering the routine childhood immunisation schedule, which saw members of the FDA and the Centres for Disease Control (CDC) vote to reduce the recommended number of vaccines at birth from 18 to 11. However, a federal judge later put this policy upheaval on ice after blocking the changes.

Høeg’s exit as acting lead of the FDA’s Centre for Drug Evaluation and Research (CDER) comes just days after the FDA’s commissioner, Marty Makary, stepped down from his role at the agency. His resignation came a little after US President Donald Trump reportedly signed off on Makary’s ousting, following disputes around the approval of fruit-flavoured e-cigarettes. Upon Makary’s resignation, the leader of the FDA’s food division, Kyle Diamantas, was named as acting commissioner.

Uncertainty continues at the FDA

While Høeg’s departure from the FDA marks another notable upturn in senior management at the agency, she will not be the only high-level regulator leaving, as Katherine Szarama has also been fired from her position as the acting head of vaccines just days after taking the helm, reports The Guardian.

Meanwhile, the FDA’s ex-chief of staff, Jim Traficant, has also been ousted, further heightening instability at the agency, which has recently contended with mass layoffs and accusations of its politicisation.

The upheaval in senior staff at the agency follows a broader shake-up within the US Department of Health & Human Services (HHS), as some Republicans fear that RFK Jr’s controversial efforts to upturn long-standing US vaccine policy could alienate voters as the midterm elections inch closer.

To quell this fear, Kennedy’s right-hand man and director of Medicare, Chris Klomp, is looking to remove controversial appointees across the HHS and replace them with more traditional options.