Elsevier

Journal of Clinical Virology

Volume 96, November 2017, Pages 37-43
Journal of Clinical Virology

Full length article
Respiratory syncytial virus hospitalization in middle-aged and older adults

https://doi.org/10.1016/j.jcv.2017.09.001Get rights and content

Highlights

  • We sought to describe the epidemiology and clinical severity of RSV compared to influenza in adults ≥18 years.

  • The highest proportion of RSV-associated hospitalizations was among adults 50-64 years and those with chronic illnesses.

  • Clinical severity of RSV-associated hospitalizations was similar to influenza-associated hospitalizations.

  • Our findings suggest a potential benefit of including adults < 65 years old in future RSV vaccination strategies.

Abstract

Background

The importance of Respiratory Syncytial Virus (RSV) is increasingly recognized in hospitalized adults, but mainly in those ≥ 65 years.

Objectives

We sought to describe the epidemiology and clinical severity of RSV compared to influenza in hospitalized adults ≥18 years.

Study design

Adults hospitalized with acute respiratory illnesses (ARI) of ≤10 days duration were prospectively enrolled from two Michigan hospitals during two influenza seasons. Collected specimens were tested for RSV and influenza by real-time, reverse transcription polymerase chain reaction (RT-PCR). Viral load and subtype were determined for RSV-positive specimens. We evaluated factors associated with RSV and outcomes of infection using multivariable logistic regression. RSV-positive patients were separately compared to two reference groups: RSV-negative and influenza-negative, and influenza-positive patients.

Results

RSV was detected in 84 (7%) of 1259 hospitalized individuals (55 RSV-B, 29 RSV-A). The highest prevalence was found in 50–64 year olds (40/460; 8.7%); 98% of RSV cases in this age group had at least one chronic comorbidity. RSV detection was associated with obesity (OR: 1.71 95% CI: 0.99-3.06, p = 0.03). Individuals with RSV were admitted to the hospital later in their illness and had a higher median Charlson comborbidity index (3 vs 2 p < 0.001) compared to those with influenza. Clinical severity of RSV-associated hospitalizations was similar to influenza-associated hospitalizations.

Discussion

In this study we observed the highest frequency of RSV-associated hospitalizations among adult 50–64 years old; many of whom had chronic comorbidities. Our results suggest the potential benefit of including these individuals in future RSV vaccination strategies.

Section snippets

Background

Respiratory Syncytial Virus (RSV), commonly regarded as a childhood infection, is also an important contributor to respiratory illness among adults [1], [2], [3], [4], [5], [6], [7], [8]. However, unlike influenza, in which serious morbidity has been clearly recognized for years, the relative impact of RSV infection in adults has more recently gained widespread recognition [9], [10]. While primary RSV infections in infancy can result in severe disease, subsequent infections are often

Objectives

Establishing the burden of severe RSV has added urgency given the accelerating development of RSV vaccines; a major issue for vaccination programs will be identifying target populations for rational use. We sought to characterize the frequency and clinical severity of RSV among hospitalized adults ≥18 years, overall and by subtype, for two respiratory illness seasons in two large Southeast Michigan hospitals.

Study design

We used specimens and data from a prospective study of adults hospitalized with ARI meeting a standardized case definition [19]. The ongoing, case-test negative study was designed to estimate influenza vaccine effectiveness (VE) in the prevention of influenza-associated hospitalization. Patients ≥18 years old hospitalized with ARI at one of two hospitals were prospectively identified from November 2014–March 2015 and November 2015–April 2016. These hospitals are two large tertiary care centers

Detection of RSV and influenza

1306 patients hospitalized for ARI were enrolled in the study between November 2014–March 2015 and November 2015–April 2016 (Fig. 1). Subsequent enrollments of individuals enrolled multiple times (n = 42) and subjects with missing or inconclusive influenza testing results (n = 3) were excluded, resulting in a study population of 1261 patients (726 in 2014–2015, 535 in 2015–2016). Fig. 1 presents RSV and influenza epidemic curves by season. Overall, RSV was detected in 86 (7%) and influenza was

Discussion

Adults ≥65 years old have long been the focus of targeted efforts to reduce the burden of hospitalization due to severe respiratory illness. Even now that yearly influenza vaccination recommendations have been extended to adults of all ages, efforts still continue to improve vaccines for older individuals including the introduction of high dose formulations. Thus, it is no surprise that recent initiatives to develop an RSV vaccine for adults have targeted those 60–65 years and older. However,

Fundings

This work was supported by the Centers for Disease Control and Prevention (CDC) through two co-operative agreements with the University of Michigan [grant numbers U01IP000474 and U01 IP000974].

Disclaimer

The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention or funding agency.

Acknowledgements

REM, ETM and ASM report a grant from MUGAS outside the current work. ETM reports grants from Merck and Pfizer outside the current work. ASL reports grants from the Doris Duke Charitable Foundation outside the current work. ASM reports grants and personal fees from Sanofi-Pasteur, and personal fees from Novartis and Protein Sciences outside the submitted work.

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    Authors REM and ETM contributed equally to this manuscript.

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