After avoiding major funding cuts, the National Institutes of Health is operating with a leadership shortfall: acting officials now lead more than half of the agency’s 27 institutes and centers. The turnover followed high-profile departures and terminations during the current administration, leaving research centers without permanent directors and complicating long-term strategy for grantmaking, clinical trials and agency policy. The leadership vacuum raises concerns among university research offices and principal investigators about funding continuity, program priorities and the agency’s ability to shepherd multiyear research initiatives.