Clinical outcomes in non-pregnant adults aged ≥ 18 years hospitalized with laboratory-confirmed RSV infection, 12 U.S. states, October 2014–April 2022
Presenter: Michael Melgar, MD, medical epidemiologist at the Centers for Disease Control and Prevention, Atlanta, GA, United States.
Among nonpregnant adults with respiratory syncytial virus (RSV)-associated hospitalization, severe illness was more common with older age and cardiopulmonary conditions, according to Michael Melgar, MD, a medical epidemiologist at the Centers for Disease Control and Prevention, Atlanta, GA, United States. Immune compromise or asthma, he said in an ID Week 2023 oral presentation, was more likely in younger adults hospitalized with RSV.
While the clinical presentation of RSV in adults is usually mild or even asymptomatic, with certain underlying medical conditions, RSV is an important cause of respiratory illness and hospitalization, usually through lower respiratory tract infection or exacerbation of existing conditions, Melgar said.
The annual RSV burden among US adults ages 65 years or older encompasses 900,000 to 1,400,000 medical encounters, 60,000 to 160,0000 hospitalizations, and 6,000 to 10,000 deaths, Melgar said, adding: “There is substantial uncertainty in burden of disease, reflected in wide ranges here.” The current Centers for Disease Control RSV recommendation is for a single dose of RSV vaccine using shared clinical decision-making among adults age 60 years or older.
“With novel RSV vaccines in development, it is critical to identify adults at increased risk of severe illness.” Melgar stated. He and colleagues calculated age-adjusted percentages, stratified by underlying conditions and demographic characteristics, of intensive care unit (ICU) admission, mechanical ventilation, and in-hospital death in adults hospitalized with RSV. For this, they used population-based surveillance conducted through the RSV Hospitalization Surveillance Network between 2014 and 2022 across 75 counties in 12 states, which included nonpregnant adults (≥ 18 years) residing in the RSV-NET catchment area who were hospitalized with laboratory-confirmed RSV infection (clinician-directed testing) during each season (October–April, except 2020–2021, which spanned October 2020–September 2021).
The surveillance, Melgar noted, encompassed 8.6% of the US population. Among the 13,080 adult RSV-associated hospitalizations over 8 seasons, 61.9% were among patients 65 years or older. The race and ethnicity make-up was 62% White, 20% Black, 8% Hispanic or Latino, and 6% Asian or Pacific Islander.
Chronic condition frequency increased directly with age for chronic kidney disease, congestive heart failure, and coronary artery disease. Also, in-hospital death rates ascended directly with older age. On the other hand, the rate of ICU admissions was 18.6%, with the highest rate among younger patients (18–49 years) and lowest rates among patients 75 years and older. Rates of mechanical ventilation and death were 7.2% and 4.2%, respectively. While the most common underlying conditions in younger adults (18–49 years) were immune compromise (34.8%) and asthma (29.8%), in-hospital death occurred most often in adults with nonasthma chronic lung disease (chronic lung disease 5.0%; chronic obstructive pulmonary disease [COPD] 5.7%). Also, the highest age-adjusted percentages of ICU admission and need for mechanical ventilation were among adults with nonasthma chronic lung disease.
Analysis of the highest rates of age-adjusted percentages of adults with severe clinical outcomes revealed ICU admission rates of 24.1% for COPD and 23.8% for heart failure, and mechanical ventilation rates of 10.0% for COPD, 9.4% for neurologic disorders, and 9% for heart failure. The highest in-hospital death rates were 6.2% for heart failure, 6.0% for coronary artery disease, and 5.7% for COPD.
Summarizing, Melgar observed that chronic conditions among adults hospitalized with RSV differ by patient age. Overall, the underlying condition most strongly associated with ICU admission, mechanical ventilation and in-hospital death was cardiopulmonary disease. Melgar concluded by emphasizing the value of describing the characteristics of adults with severe RSV illness: “It may help assist clinicians in engaging in shared clinical decision-making with their patients regarding RSV vaccination and to inform future public health recommendations.” He added, “Older adults with cardiopulmonary and immune compromising conditions may benefit from RSV vaccination when licensed products become available.”
Melgar noted that a limitation of the study was that the investigators’ use of clinician-driven testing likely underdetected RSV-associated hospitalizations.
Disclosures. Dr. Melgar had no disclosures.