Dr. Crotty’s research focuses on understanding the immunobiology underlying vaccine function, with particular interest in the roles of these mechanisms in human viral vaccines and protection from infectious diseases. He is recognized worldwide for developing devising ways to stimulate protective B cells responses to HIV and other viruses. Dr. Crotty is internationally recognized as a leader in T follicular helper cell (Tfh) Field and defined critical aspects of Tfh cellular and molecular biology that led to important advances in vaccine development. In collaboration with Dr. Sette and as a Member of the LJI Corona Task Force, Dr. Crotty showed that long-lasting immune protection to COVID-19 infections is established by combined efforts between B and T cells and that tSARS-CoV-2 pre-existing immune reactivity exists to some degree in the general population.