Core Viewpoint - The approval of Moderna's RSV vaccine for younger adults indicates a potential easing of the previous administration's resistance to mRNA vaccine technology, allowing the company to target a larger market segment [1][2]. Group 1: Regulatory Approvals - The U.S. FDA has approved Moderna's RSV vaccine for adults under 60 who are at high risk of respiratory syncytial virus (RSV) infection, expanding its market reach [1]. - This approval follows the FDA's earlier authorization of the same vaccine for individuals aged 60 and above, marking the second mRNA vaccine product for Moderna after its COVID-19 vaccine [1][2]. Group 2: Competitive Landscape - Competitors such as Pfizer and GlaxoSmithKline have also received approvals for their RSV vaccines targeting high-risk populations, with Pfizer allowed to sell to those under 60 and GlaxoSmithKline to those aged 50 to 59 [1][2]. - The global market now features three adult RSV vaccines: Moderna's mRNA-1345, Pfizer's Abrysvo™, and GlaxoSmithKline's Arexvy™, each utilizing different technological platforms and formulations [2][3]. Group 3: Vaccine Technology and Efficacy - Moderna's mRNA-1345 vaccine employs a single mRNA strand encoding the pre-F protein, encapsulated in lipid nanoparticles, which allows for rapid updates and high neutralizing antibody titers with a single injection [3]. - In contrast, Pfizer and GlaxoSmithKline utilize recombinant protein vaccines with adjuvants, which may offer better immune persistence but require more complex manufacturing processes [3].