Characteristics and Outcomes Among Adults Aged ≥60 Years Hospitalized with Laboratory-Confirmed Respiratory Syncytial Virus — RSV-NET, 12 States, July 2022–June 2023

Abstract

Respiratory syncytial virus (RSV) causes substantial morbidity and mortality in older adults. In May 2023, two RSV vaccines were approved for prevention of RSV lower respiratory tract disease in adults aged ≥60 years. In June 2023, CDC recommended RSV vaccination for adults aged ≥60 years, using shared clinical decision-making. Using data from the Respiratory Syncytial Virus–Associated Hospitalization Surveillance Network, a population-based hospitalization surveillance system operating in 12 states, this analysis examined characteristics (including age, underlying medical conditions, and clinical outcomes) of 3,218 adults aged ≥60 years who were hospitalized with laboratory-confirmed RSV infection during July 2022–June 2023. Among a random sample of 1,634 older adult patients with RSV-associated hospitalization, 54.1% were aged ≥75 years, and the most common underlying medical conditions were obesity, chronic obstructive pulmonary disease, congestive heart failure, and diabetes. Severe outcomes occurred in 18.5% (95% CI = 15.9%–21.2%) of hospitalized patients aged ≥60 years. Overall, 17.0% (95% CI = 14.5%–19.7%) of patients with RSV infection were admitted to an intensive care unit, 4.8% (95% CI = 3.5%–6.3%) required mechanical ventilation, and 4.7% (95% CI = 3.6%–6.1%) died; 17.2% (95% CI = 14.9%–19.8%) of all cases occurred in long-term care facility residents. These data highlight the importance of prioritizing those at highest risk for severe RSV disease and suggest that clinicians and patients consider age (particularly age ≥75 years), long-term care facility residence, and underlying medical conditions, including chronic obstructive pulmonary disease and congestive heart failure, in shared clinical decision-making when offering RSV vaccine to adults aged ≥60 years.

Introduction

Respiratory syncytial virus (RSV) causes substantial morbidity and mortality in older adults, resulting in approximately 60,000–160,000 hospitalizations and 6,000–10,000 deaths annually among adults aged ≥65 years (1). In May 2023, the Food and Drug Administration approved two RSV vaccines for prevention of RSV lower respiratory tract disease in adults aged ≥60 years.* In June 2023, CDC recommended RSV vaccination for adults aged ≥60 years using shared clinical decision-making between patient and clinicians;^† adults at highest risk for severe RSV disease are most likely to benefit and should be prioritized for vaccination (1). To describe persons who experienced severe RSV disease requiring hospitalization, data from a large, geographically diverse surveillance system were analyzed to identify characteristics of adults aged ≥60 years hospitalized with laboratory-confirmed RSV infection during the 2022–23 respiratory virus season.

Methods

The Respiratory Syncytial Virus–Associated Hospitalization Surveillance Network (RSV-NET)^§ conducts population-based surveillance for RSV-associated hospitalizations in approximately 300 hospitals in 58 counties across 12 states,^¶ covering approximately 9% of the U.S. population. RSV-NET identifies residents within the network catchment area who are hospitalized with positive RSV tests results for provider-ordered reverse transcription–polymerase chain reaction (RT-PCR) or rapid antigen detection tests during their hospitalization or during the 14 days preceding admission.

Because the 2022–23 RSV season started earlier than did seasons preceding the COVID-19 pandemic (2), this description of demographic characteristics of hospitalized RSV-NET patients includes those hospitalized during July 1, 2022–June 30, 2023. Using previously described methods (3), clinical data were collected by trained surveillance officers from a random sample of medical charts for adults hospitalized during October 1, 2022–April 30, 2023, and stratified by age and site. Sampled data are presented as unweighted case counts and weighted percentages that were weighted for the probability of selection and adjusted to better represent the hospitalized population of the catchment area (3). Age distributions of patients aged ≥60 years who were hospitalized and experienced severe outcomes, defined as intensive care unit (ICU) admission, mechanical ventilation, and in-hospital death, were compared with the overall age distribution of persons ≥60 years in the RSV-NET catchment area. Underlying medical conditions among hospitalized patients and those with severe outcomes were assessed and described. Data were analyzed using SAS survey procedures (version 9.4; SAS Institute). Differences were assessed using chi-square tests; p-values <0.05 were considered statistically significant. This activity was reviewed by CDC, deemed not research, and was conducted consistent with applicable federal law and CDC policy.**

Results

Among 3,218 adults aged ≥60 years with an identified RSV-associated hospitalization during July 2022–June 2023, a total of 1,738 (54.0%) were aged ≥75 years (this group constituted 29.0% of the catchment population of adults aged ≥60 years); 434 (13.5%) and 1,208 (37.5%) of RSV-associated hospitalizations occurred in persons aged 60–64 and ≥80 years, respectively. Overall, 222 (6.9%) patients were Hispanic or Latino (Hispanic), 2,159 (67.2%) patients were non-Hispanic White (White), 496 (15.4%) non-Hispanic Black or African American (Black), 228 (7.1%) non-Hispanic Asian or Pacific Islander (A/PI), 13 (0.4%) non-Hispanic American Indian or Alaska Native (AI/AN) persons, and 100 (3.2%) persons were of other or unknown race. The median patient age was 75 years (IQR = 68–84 years). The median age of White patients (77 years; IQR = 69–85 years) was significantly higher than that of patients who were Black (70 years; IQR = 65–77), Hispanic (74 years; IQR = 66–83 years), or AI/AN (72 years; IQR = 71–75 years) and was lower than that among A/PI (79 years; IQR = 71–87 years) patients (p-value <0.01 for all) (Supplementary Table 1; https://stacks.cdc.gov/view/cdc/133296). The proportion of hospitalized patients whose race was reported as Hispanic or Black decreased with increasing age (p-value <0.01); Black patients accounted for 28.2% of hospitalized patients aged 60–64 years and 8.2% of those aged ≥80 years (Supplementary Table 2; https://stacks.cdc.gov/view/cdc/133297).

Among a random sample of 1,634 adults aged ≥60 years hospitalized during October 2022–April 2023 whose medical charts were reviewed, 54.1% were aged ≥75 years, and 290 (17.2%) were long-term care facility (LTCF) residents, including 175 (26.9%) of those aged ≥80 years (Table). Nearly all patients (1,553 [95%]) had SARS-CoV-2 test results available, among which 39 (2.4%) were positive; 1,587 (97.1%) had influenza testing results, among which 23 (2.2%) were positive.^†† Prevalence of severe outcomes was not higher among patients with viral codetections compared with those with RSV alone detected (p>0.5). The median length of hospitalization was 4.1 days (IQR = 2.2–7.6 days). A substantial proportion (332 [18.5%; 95% CI = 15.9%–21.2%]) of patients had at least one severe outcome, including 297 (17.0%) who required ICU admission, 94 (4.8%) who required mechanical ventilation, and 98 (4.7%) who died while hospitalized.

Almost all sampled patients (1,584; 95.5%) had at least one underlying medical condition, most commonly obesity (37.8%), chronic obstructive pulmonary disease (COPD) (33.7%), congestive heart failure (CHF) (33.2%), and diabetes mellitus (32.6%); 18.6% had an immunocompromising condition (Table) (Figure 1). The following underlying conditions were significantly more prevalent in patients with severe outcomes than in those without severe outcomes: COPD (40.0% versus 32.0%; p = 0.047), other chronic lung diseases excluding COPD and asthma (9.1% versus 4.4%; p = 0.04), and CHF (41.2% versus 31.4%; p = 0.01).

Whereas adults aged 75–79 years and ≥80 years accounted for 12.4% and 16.2% of the catchment area populations, respectively (Figure 2), they accounted for 16.0% (95% CI = 13.5%–18.8%) and 38.1% (95% CI = 34.7%–41.7%) of hospitalizations, 21.2% (95% CI = 13.2%–31.3%) and 25.5% (95% CI = 18.6%–33.5%) of ICU admissions, and 25.6% (95% CI = 14.8%–39%) and 42.1% (95% CI = 29.1%–55.9%) of in-hospital deaths, respectively. Orders to not resuscitate or intubate were in place for 321 (20%) patients, including 211 (35%) patients aged ≥80 years.

Discussion

During July 2022–June 2023, RSV-associated hospitalizations among adults aged ≥60 years in a large population-based surveillance system occurred predominantly among those aged ≥75 years (54%); many (17.2%) of these patients resided in long-term care facilities. The median age of hospitalized AI/AN, Black, and Hispanic patients was lower than that of hospitalized White patients. Viral coinfections reported in RSV-NET were infrequent, despite comprehensive testing for SARS-CoV-2 and influenza, indicating that RSV alone caused substantial morbidity and mortality in this population. Most patients hospitalized with RSV had underlying medical conditions, notably CHF and COPD, which were associated with severe outcomes. Severe outcomes were common, with 17.0% of hospitalized patients requiring ICU admission and nearly 5% dying during their hospitalization.

CDC recommends RSV vaccination for adults aged ≥60 years using shared clinical decision-making, which may consider a patient’s individual risk for severe disease (1). Adults aged ≥75 years were overrepresented among older adult RSV-NET hospitalizations, consistent with previous studies demonstrating increased RSV hospitalization rates with increasing age (4,5). However, the median age of hospitalized older adults who were AI/AN, Black, and Hispanic patients was lower than that for White patients, such that persons in these three groups accounted for a larger proportion of RSV-NET hospitalizations among the younger age groups. This finding likely reflects different age distributions, as well as life expectancy, within the catchment population, as well as potentially higher risk for hospitalization at younger ages resulting from racial and ethnic disparities in underlying medical conditions, access to medical care, and socioeconomic status (6–8).

The prevalence of underlying medical conditions among hospitalized patients was high, including CHF and COPD, both of which were disproportionately associated with severe outcomes in this analysis. Both CHF and COPD have been previously associated with increased RSV hospitalization rates (4,5). One study indicated that older adults with COPD (aged ≥65 years) and CHF (aged 60–79 years) had RSV hospitalization rates that were 3.5–13.4 times and 5.9–7.6 times higher, respectively, than rates among those without those conditions (5). The large proportion of LTCF residents among RSV-NET hospitalizations is also consistent with published literature demonstrating this population’s vulnerability to institutional outbreaks and hospitalization (9).

Limitations

The findings in this report are subject to at least three limitations. First, RSV-associated hospitalizations might have been missed because of test availability or clinician testing practices that limit RSV testing among hospitalized adults. Second, and conversely, severely ill patients might have been more likely to undergo RSV testing, potentially overestimating the proportion of severe outcomes among hospitalized patients. Finally, because RSV-NET covers 9% of the U.S. population, these findings might not be nationally generalizable.

Implications for Public Health Practice

RSV causes substantial morbidity and mortality in adults aged ≥60 years; these findings suggest that advanced age (particularly ≥75 years), LTCF residence, and the presence of underlying medical conditions, including COPD and CHF, might be risk factors for clinicians and patients to consider in shared decision-making regarding RSV vaccination. It is important that special attention be paid to equitable access to vaccines for AI/AN, Black, and Hispanic adults, who were hospitalized for RSV at younger ages than were White adults.

RSV-NET Surveillance Team

Pam Daily Kirley, California Emerging Infections Program; Elizabeth Austin, Colorado Department of Public Health & Environment; Daewi Kim, Connecticut Emerging Infections Program, Yale School of Public Health; Chandler Surell, Emory University School of Medicine, Georgia Emerging Infections Program, Georgia Department of Public Health, Atlanta Veterans Affairs Medical Center; Maya Monroe, Maryland Department of Health; Lauren Leegwater, Michigan Department of Health & Human Services; Erica Mumm, Minnesota Department of Health; Molly Bleecker, University of New Mexico Emerging Infections Program; Adam Rowe, New York State Department of Health; Kevin Popham, University of Rochester School of Medicine and Dentistry; Arilene Novak, Public Health Division, Oregon Health Authority; William Schaffner, Vanderbilt University Medical Center; Holly Staten, Salt Lake County Health Department.