An age expansion for a respiratory syncytial virus (RSV) vaccine has won regulatory backing in Europe, potentially opening access far beyond the older-adult population originally covered.

At its March 2026 meeting, the European Medicines Agency’s (EMA’s) Committee for Medicinal Products for Human Use recommended expanding the authorization for the RSV vaccine mResvia (Moderna Biotech Spain) from adults aged 60 years or older to adults aged 18 years or older. That means the revised indication is no longer limited to older adults or to younger adults at increased risk; it now covers all adults aged 18 years or older for prevention of lower respiratory tract disease caused by RSV. 

The draft expansion goes beyond a risk-based carveout and instead broadens eligibility to the full adult population. That said, the vaccine may still be particularly relevant for younger adults with underlying comorbidities that increase the risk for severe RSV-related disease, including cardiovascular disease, chronic respiratory disease, and diabetes.

How the Vaccine Works 

mResvia contains messenger RNA instructions for producing the RSV-A glycoprotein F, a surface protein the virus needs to enter cells. When given, the vaccine prompts cells to temporarily produce this protein, triggering immune system recognition and antibody production against both RSV-A and RSV-B subtypes.

The vaccine is administered as a single intramuscular injection in the upper arm. Clinicians should continue to follow official national health body guidelines when recommending immunization.

Immunogenicity Evidence 

The recommendation was supported by immunobridging data from an ongoing phase 3 trial in adults aged 18-59 years at increased risk for RSV-associated lower respiratory tract disease. 

Among the 502 participants who received the licensed 50-µg dose, neutralizing antibody responses at day 29 were noninferior to those observed in adults aged 60 years or older in the pivotal efficacy trial, with geometric mean titer ratios of 1.2 for RSV-A and 1.1 for RSV-B. Antibody levels remained above baseline through 6 months, supporting inference of efficacy in this at-risk younger adult population.

Safety Outcomes 

Safety data indicated that although 74.5% of participants reported local reactions (primarily injection site pain) and 52% reported systemic reactions, most events were mild to moderate and resolved within two days. 

Common systemic effects included fatigue (36.9%), headache (33.3%), and myalgia (28.9%). 

One case of Bell palsy occurred 43 days post‑vaccination in the 30‑µg group; multiple confounding conditions and delayed onset limited causality assessment.

There were no reported cases of anaphylaxis, Guillain-Barré syndrome, or myocarditis.

The vaccine remains under additional monitoring. Detailed product recommendations will appear in the updated Summary of Product Characteristics on the EMA website following European Commission marketing authorization.