mRESVIA is now approved in the U.S. for adults aged 18 to 59 with chronic health conditions. The approval expands its prior indication that was limited to adults aged 60 years and older.

Adults aged 18 to 59 years with chronic conditions—including cardiovascular and pulmonary diseases—are increasingly recognized as a high-risk population for respiratory syncytial virus (RSV)-related complications, including respiratory tract disease. Recent estimates suggest that more than one-third of adults in this age group have comorbidities that are associated with heightened risk of severe RSV outcomes. Disease burden and hospitalization rates in this group are comparable to those seen in older adults.

The FDA's approval was supported by results from Moderna's phase 3 study (NCT06067230), which evaluated the safety and immunogenicity of mRESVIA (mRNA-1345) in adults aged 18 to 59 with underlying health conditions. Immune responses to both RSV-A and RSV-B met prespecified noninferiority criteria when compared with older adults who received the vaccine in a prior randomized, placebo-controlled phase 3 trial. Neutralizing antibody titers were consistent across both the 18 to 49 and 50 to 59 age subgroups, and supported the vaccine’s immunogenicity across the expanded age range. These results were presented to the CDC’s Advisory Committee on Immunization Practices in April 2025 and published in Clinical Infectious Diseases.

Solicited adverse reactions in the 18 to 59 age cohort were generally mild to moderate and included injection site pain, fatigue, headache, myalgia, and arthralgia.

mRESVIA is an mRNA vaccine that encodes a stabilized prefusion F glycoprotein, the primary antigenic target for neutralizing antibodies against RSV-A and RSV-B. The vaccine uses the same lipid nanoparticle platform as Moderna’s COVID-19 vaccines. Distribution for adults aged 18 and older is anticipated ahead of the 2025 to 2026 respiratory virus season.

Source: Moderna, Inc