Respiratory syncytial virus (RSV) is associated with a high disease burden in older adults and those with comorbidities, and a number of vaccines are currently in development, investigators reported in Clinical Microbiology and Infection.

Researchers conducted a narrative review that focused on RSV burden in older patients and provided an update on the recent developments in patient management.

The investigators performed a literature search in PubMed from August 2022 to August 2023 to identify studies on RSV in the adult population, as well as in for registered ongoing trials of RSV vaccines, monoclonal antibodies, and other antivirals.

Recent evidence has reported on the burden of RSV infection in older adults. This ranges from mild symptoms to increased hospitalization rates and more severe diseases, including an increased risk for intensive care unit (ICU) admission or mortality among hospitalized patients with RSV compared with hospitalized patients with influenza. Other evidence has shown that patients with RSV had greater pre-existing comorbidities and that hospitalization with laboratory-confirmed RSV infection was associated with acute and prolonged functional loss.

The coming years promise to be extremely exciting in the RSV prevention landscape. The best use of the new prevention, diagnostic, and therapeutic tools must be defined.

Phase 3 trial results have been reported for 2 subunit vaccines using the RSV pre-F protein. A bivalent vaccine involving subtype A and B of RSV pre-F proteins (RSVpreF) showed high efficacy in younger adults. The phase 3 RENOIR trial ( Identifier: NCT05035212) assessed this vaccine in older patients, and preliminary findings demonstrated efficacy for preventing RSV-associated lower respiratory tract infection (LRTI) with at least 2 or 3 signs or symptoms of 66.7% and 85.7%, respectively.

The monovalent vaccine involves RSVpre-F protein, adjuvanted with AS01. Preliminary findings from the AReSVi-006 phase 3 trial ( Identifier: NCT04886596) showed efficacy of 94.1% for severe RSV-related lower respiratory tract disease.

These trials are ongoing, but both vaccines were approved in Spring 2023 by the US Food and Drug Administration (FDA) for active immunization in individuals aged 60 years and older for the prevention of lower respiratory tract disease caused by RSV. The FDA also has approved RSVPreF for use in pregnant women.

Nirsevimab, a new half-life-extended monoclonal antibody, was recently approved by the FDA for preventing serious lower respiratory tract infection caused by RSV in children at high risk of RSV disease. Clesrovimab, another long-acting monoclonal antibody, is being investigated in a phase 3 study ( Identifier: NCT04938830).

Ribavirin has not significantly affected clinical outcomes in immunocompromised and older adults, including mortality, length of hospital stay, mechanical ventilation, or ICU admission.

Fusion inhibitors are also being studied for RSV treatment. Presatovir had a good safety profile and efficacy for reducing viral load and clinical symptoms in a phase 2 human challenge ( Identifier: NCT02254408).

No significant evidence has shown a positive effect of glucocorticoids in RSV-related infection, although they are widely used in RSV-infected patients and benefits were observed during the COVID-19 pandemic

The effect of RSV “on at-risk adult is still under-recognized due to the lack of awareness among healthcare professionals and the general population, the lack

of systematic use of virological diagnostics and a robust data collection and surveillance systems, and the absence of RSV-targeted treatments,” noted the study authors. “The coming years promise to be extremely exciting in the RSV prevention landscape. The best use of the new prevention, diagnostic, and therapeutic tools must be defined. The viral evolution and resistance must also be studied to guide new monoclonal antibodies, antivirals and vaccines elaboration in child and adult populations.

Disclosure: Some of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.

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