Moderna's mRESVIA, their respiratory syncytial virus (RSV) vaccine, has recently secured expanded approval from the U.S. Food and Drug Administration (FDA) to include individuals aged 18-59 who are at increased risk for severe RSV disease. This approval significantly broadens the vaccine's reach, as it was initially cleared in May 2024 for adults 60 years and older. The decision to include younger at-risk adults, such as those with chronic conditions, stems from compelling Phase 3 clinical trial data (NCT06067230) which demonstrated that mRESVIA effectively generated immune responses comparable to those seen in the older age group, meeting non-inferiority criteria. Moderna highlighted that these younger adults with underlying health issues face a comparable, and sometimes even higher, burden of RSV-related disease and hospitalization rates as older adults, making this expanded indication crucial for public health. The vaccine was generally well-tolerated, with common side effects being mild and temporary, such as injection site pain, fatigue, and headache. Moderna anticipates having mRESVIA readily available for both the newly approved younger adult demographic and the previously approved older adult population for the upcoming 2025-2026 respiratory virus season.