Is RSV a Live Vaccine?
No, the currently approved RSV vaccines for adults are NOT live vaccines—they are recombinant protein subunit vaccines or mRNA vaccines that contain no live viral particles and cannot replicate in the human body. 1
Vaccine Types Currently Approved
The three FDA-approved RSV vaccines for adults are all non-live formulations:
Arexvy (RSVPreF3) is a recombinant RSV pre-fusion F protein adjuvanted with AS01E, approved for adults ≥50 years—this is a completely inactivated protein subunit vaccine containing purified RSV fusion protein antigens with no live viral particles 1, 2
Abrysvo (RSVpreF) is a recombinant bivalent RSV-A and RSV-B pre-fusion F protein vaccine, approved for adults ≥60 years—also a non-replicating protein subunit formulation 3, 2
mRESVIA (mRNA-1345) is an mRNA vaccine approved for adults ≥60 years—this uses messenger RNA technology and contains no live virus 3
Clinical Implications of Non-Live Formulation
The non-live nature of these vaccines has important practical consequences:
Safe for immunocompromised patients: These vaccines can be safely administered to cancer patients, those on immunosuppressive therapy, and elderly patients with multiple comorbidities because they cannot cause infection 1
No special precautions required: Unlike live vaccines, no special timing considerations or contraindications apply regarding immunosuppression status 1
Similar design to other successful vaccines: The recombinant protein subunit vaccines are similar in design to the recombinant zoster vaccine, which has an established safety profile 1
Historical Context
While live attenuated RSV vaccines (cold-passaged, temperature-sensitive variants) have been evaluated in clinical trials historically and may be useful for young infants in the future, none are currently approved for use 4, 5, 6. The development pathway focused on non-live formulations specifically to avoid safety concerns and ensure suitability for high-risk populations including the elderly and immunocompromised individuals 7.