Understanding RSV and Why It’s a Threat to Seniors

Respiratory Syncytial Virus (RSV) is a common respiratory virus that usually causes mild, cold-like symptoms. Though, for older adults, RSV can lead to severe illness, including pneumonia and hospitalization.Before the development of vaccines, RSV was estimated to cause approximately 60,000-160,000 hospitalizations and 6,000-10,000 deaths annually among adults 65 years and older in the United States.

The virus spreads through close contact with infected individuals, often via respiratory droplets produced during coughing or sneezing. Older adults are especially vulnerable due to age-related decline in immune function and the presence of underlying health conditions like heart disease or chronic lung disease.

The New RSV Vaccine: How It Works and What the Trials Showed

The newly approved vaccine, arexvy, manufactured by GSK, is a recombinant subunit vaccine. This means it doesn’t use a live virus. Instead, it contains a stabilized version of the RSV fusion (F) protein, which prompts the immune system to create antibodies that protect against the virus.

Clinical trials, detailed in the October 9, 2025 issue of the New England Journal of Medicine, demonstrated a vaccine efficacy of 82.6% against RSV-associated lower respiratory tract disease (LRTD) in adults 60 years and older.The trials involved over 20,000 participants and showed a consistent benefit across different age groups and underlying health conditions. Specifically, the vaccine demonstrated efficacy against both RSV-A and RSV-B strains.

The most common side effects reported in the trials were injection-site pain,fatigue,muscle aches,headache,and joint pain. serious adverse events were rare and not definitively linked to the vaccine.

Who Should Get the RSV Vaccine?

The FDA approved Arexvy for adults aged 60 years and older. The Centers for Disease Control and Prevention (CDC) Advisory Committee on Immunization Practices (ACIP) will provide further recommendations regarding who should receive the vaccine, taking into account individual risk factors and preferences.

The CDC is expected to recommend shared clinical decision-making, meaning that individuals should discuss the benefits and risks of vaccination with their healthcare provider to determine if it’s right for them. Factors to consider include age, overall health status, and risk of RSV exposure.

RSV Vaccine vs. Monoclonal Antibody: What’s the Difference?

Along with the vaccine, the FDA also previously approved Beyfortus, a monoclonal antibody, for infants to protect against RSV. It’s crucial to understand the difference. Vaccines stimulate the body’s own immune system to create long-lasting protection. Monoclonal antibodies provide immediate, but temporary, protection by directly supplying antibodies.

The RSV vaccine is designed for older adults to proactively build immunity, while Beyfortus is a passive immunization strategy for infants who lack a fully developed immune system.