Eli Lilly has agreed to buy three vaccine developers in coordinated deals totaling up to nearly $4 billion, extending the company’s push to prevent disease rather than just treat downstream consequences. The acquisitions target infectious disease vaccine R&D and add clinical-stage and platform assets that Lilly says complement its broader strategy. Separately, Lilly’s expanding vaccine agenda is also tied to its leadership move in infectious disease, including the hiring of Peter Marks—former head of the FDA’s vaccine division—signaling a longer-term commitment to vaccine development. For investors and partners, the combination of large up-front commitments and milestone-driven structures suggests Lilly is prioritizing speed to pipeline build while leveraging manufacturing and immunology know-how across multiple pathogen targets.