Respiratory Syncytial Virus Vaccines: Who, When, and Which Vaccine? A Practical Guide for Clinicians

Respiratory syncytial virus (RSV) is a major cause of severe respiratory illness and hospitalization in older adults with chronic cardiopulmonary or metabolic conditions. After six decades without a preventive option, three RSV vaccines are now available: an adjuvanted prefusion F protein vaccine (Arexvy), a bivalent prefusion F protein vaccine (Abrysvo), and an mRNA vaccine (mResvia). All three have shown efficacy against RSV-associated lower respiratory tract disease in older adults and effectiveness against hospitalization after licensure, but none have been compared head-to-head. All three are now approved for high-risk adults younger than 60 years, and Abrysvo alone for maternal immunization at 32-36 weeks of gestation. In the United States, vaccination is recommended for all adults aged 75 years and older and for those aged 50-74 years with risk factors; these recommendations reflect United States public health policy and do not automatically apply to Korean practice. In Korea, Arexvy and mResvia are licensed and Abrysvo is under review, but only Arexvy is marketed and none is included in the National Immunization Program. Post-marketing surveillance has identified a Guillain-Barré syndrome signal with the two protein-based vaccines (fewer than 10 excess cases per million doses), although regulators judge that benefits outweigh risks. This review compares the three vaccines and summarizes practical recommendations for Korean clinicians on patient selection, timing, coadministration, revaccination, and special populations.