RSV and Aging: Understanding Increased Vulnerability

Respiratory syncytial virus (RSV) infections impact older adults harder, leading to more severe illness and death compared with younger individuals. New research published in Virology assessed how aging affects the specific immune cells that fight RSV, the underlying reasons for these changes, and the real-world impact of this weakened immunity in older adults.¹

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Impact of RSV on Older Adults

Severe RSV outcomes are more common for high-risk individuals, including those aged 75 years and older and those with chronic or underlying health conditions. Individuals infected with severe RSV typically present mild cold-like symptoms; however, some cases often need hospitalization. Conditions like asthma, chronic obstructive pulmonary disease, heart failure, and cystic fibrosis could worsen with RSV infection, according to the CDC. However, research on how RSV impacts healthy older adults is limited.²

The increased vulnerability of RSV among older adults stems from the way the immune system changes as we age, known as immunosenescence. This multifaceted aging process in cells involves changes in the metabolism, programming, and specialization. Additionally, this age-related decline in the immune system has significant consequences on how the body interacts with pathogens, hindering effective immune responses and sometimes directly contributing to disease development. The study authors noted that during RSV infection in older adults, both the initial rapid response and the later, more targeted defense struggle. This makes it easier for the virus to attack and harder for the body to clear it, throwing off the balance of immune signaling molecules.¹

Importance of Animal Models in Understanding Immunosenescence and RSV

While studies in humans have furthered understanding of how immunosenescence affects RSV in older adults, animal models also play an essential role in expanding this knowledge.¹

In the review, researchers found that the general ways the immune system weakens with age do not affect responses to all pathogens equally. For instance, while older individuals and animal models show issues with granulocyte function, this does not seem to worsen RSV infection. Instead, issues with presenting viral components to the immune system, producing antibodies, and the response to specific T cells appear to be major factors in reduced protection and slower viral clearance in older adults.¹

However, the study authors noted that future research into the precise molecular mechanisms in which immunosenescence hinders the immune response to RSV is crucial for developing better treatment.¹

Implications for Vaccine Efficacy in Older Adults

Despite the approval of 2 RSV vaccines—RSVPreF3 (Arexvy; GSK), RSVpreF (Abrysvo; Pfizer), and mRNA-1345 (mRESVIA; Moderna)—indicated for adults aged 60 years and older, the reduced effectiveness of vaccines in older adults is a well-known issue. The study authors noted that this is also observed in older animal models that face a risk of second RSV infection.¹

“As vaccines, prophylactic measures, and therapeutics targeted toward mitigating risk in elderly individuals continue to be developed, it is vital that these treatments are tested in age-appropriate animal models during early clinical trials,” the study authors said in the release.¹

The findings suggest that targeting research on the inhibition of T cell response and anti-inflammatory therapy inhibiting lipid mediators like prostaglandin D2 could help construct an appropriate vaccine and maximize responses to already available vaccines.¹

REFERENCES

1. Miller J., Niewiesk S. Review of impaired immune parameters in RSV infections in the elderly. Virology. Published January 8, 2025. Accessed April 24, 2025. https://www.sciencedirect.com/science/article/pii/S0042682225000078?via%3Dihub

2. RSV in Older Adults. CDC. News release. August 30, 2024. Accessed April 24, 2025. https://www.cdc.gov/rsv/older-adults/index.html.