US health and human services secretary Robert F Kennedy Jr has dismissed two top aides of the department, marking a sudden leadership shift just months into his tenure.Chief of staff Heather Flick Melanson and deputy chief of staff for Policy Hannah Anderson were removed from their roles this week, sources familiar with the matter told CNN. The possible reason behind the move remains unclear. An HHS spokesperson confirmed the changes and announced that Matt Buckham, the department’s White House liaison, will take over as acting chief of staff.“He brings valuable experience in personnel strategy and organizational management to this new role,” the spokesperson said as quoted by CNN. “Secretary Kennedy thanks the outgoing leadership for their service and looks forward to working closely with Mr. Buckham as the Department continues advancing its mission to Make America Healthy Again,” he added.Kennedy has not yet chosen permanent replacements.The leadership overhaul comes as HHS faces mounting scrutiny over its efforts to revise vaccine policies and push forward key health and food initiatives.Flick was one of Kennedy’s most seasoned Washington insiders, having held multiple senior roles at HHS during the Trump administration, including acting general counsel, acting secretary for administration, and senior adviser to then-Secretary Alex Azar.Anderson came to HHS with a background as a Republican staffer on Capitol Hill, where she served as a health policy adviser on the Senate’s primary health committee. Most recently, she led health care policy at the Trump-aligned America First Policy Institute.