Older age, comorbidities drivers of hospitalization for RSV

Advanced age (≥65 years) and comorbidities increase the risk of respiratory syncytial virus (RSV)-associated hospitalization, according to a presentation at IDWeek 2023.

Using data from the Medicare database, the researchers identified 756 adults (aged >18 years) who were diagnosed with RSV between 2011 and 2015. Significant predictors of hospitalization were chronic obstructive pulmonary disease (COPD; odds ratio [OR], 2.12; p<0.001), chronic heart failure (OR, 2.06; p<0.001), haematologic malignancies (OR, 5.17; p=0.001), and chronic kidney disease (OR, 4.37; p<0.001).

“There are also other socioeconomic risk factors, such as poor nutrition, smoke exposure, and overcrowding, but I believe age and comorbidities are the primary drivers [of severe RSV infection],” said Professor Helen Chu from the University of Medicine in Seattle, Washington, US.

The annual attack rate of RSV is 2–10 percent in older adults living in the community and those residing in congregate settings, particularly long-term care facilities (LTCFs).

“LTCFs are high risk for older adults because it increases the risk of transmission. Frailty and comorbidities also lead to RSV infection and subsequent hospitalization for cardiorespiratory issues,” Chu said.

In a retrospective analysis involving LTCF residents, RSV-attributable cardiorespiratory events occurred at an incidence rate of 122 events per 100,000 person-years during the study period. Long-stay residents aged ≥85 years had the highest RSV-attributable cardiorespiratory hospitalization rates (182 events per 100,000 person-years), followed by those aged 65–74 years (64 events per 100,000 person-years) and 75–84 years (53 events per 100,000 person-years). [JAMA Netw Open 2021;4:e2111806]

Recent studies have also found that older adults aged ≥75 years residing in LTCF and those with comorbidities (obesity, COPD, and heart failure) are at greater risk for hospitalization due to RSV. “This is really important to highlight. When people get hospitalized with RSV, they tend to have severe disease and they are intubated,” Chu said.

Although RSV results in fewer hospitalizations than influenza or SARS-CoV-2, older adults hospitalized with RSV were more likely to end up in the intensive care unit and die than those with influenza or SARS-CoV-2, she added.

Prevention is key

Owing to the substantial morbidity and mortality from RSV in older adults, the CDC’s Advisory Committee on Immunization Practices (ACIP) has recommended two FDA-approved RSV vaccines (RSVPreF3 and RSVpreF) for use in adults aged ≥60 years. [https://www.cdc.gov/vaccines/vpd/rsv/public/older-adults.html]

Early this year, Moderna's investigational RSV vaccine, mRNA-1345, demonstrated vaccine efficacy of 83.7 percent against RSV lower respiratory tract disease (LRTD), defined by 2 or more symptoms in older adults. mRNA-1345 was safe and well-tolerated with no safety concerns identified. The trial is ongoing, and additional efficacy analyses are planned as cases accrue, including for severe RSV. [RSVVW 2023, abstract 123]

RSV circulates in the same season as most other respiratory viruses, including seasonal coronavirus, adenoviruses, parainfluenza, rhinovirus flu, and metapneumovirus.

“The burden of RSV disease remains underestimated due to lack of testing for RSV in adults,” said Chu.

Key takeaways

“RSV causes significant morbidity and mortality in older adults,” said Prof Gregory Poland from Mayo Clinic in Rochester, Minnesota, US. “Vaccination with a single dose vaccine demonstrated moderate to reasonably high efficacy in preventing symptomatic RSV-LRTD. No less than the ACIP has recommended a single dose of RSV vaccine in individuals ≥60 years.”