FILE: scandal-hit Michel Sidibé to step down as head of UNAIDs Scandal-plagued UNAIDS head Michel Sidibé offers to resign in June, following a report that said his "defective leadership" had plunged the agency into crisis. The timeline for the departure, confirmed by the agency, amounted to a concession from a leader accused of fostering a work environment that has tolerated bullying and sexual harassment. FILE IMAGES of Michel Sidibé, head of UNAIDS.