Sanofi has agreed to acquire the vaccine-focused biotech Vicebio for $1.15 billion upfront, plus $450 million in milestone payments, expanding its respiratory syncytial virus (RSV) vaccine pipeline beyond mRNA approaches. Vicebio's lead candidate, VXB-241, currently in Phase 1, targets RSV and human metapneumovirus (hMPV). The acquisition marks Sanofi's third deal this year, driven by encouraging initial clinical evidence demonstrating safety and tolerability. This move strengthens Sanofi's position in respiratory vaccine development and underscores strategic investments in early-stage assets to diversify vaccine portfolios amid ongoing respiratory disease threats.