Hospitalized Adults with Hematological Malignancies and RSV Infection: Paving the Way for Universal RSV Vaccination?
Authors: Vojjala Nikhil , Kattamuri Lakshmi Vaishnavi , Kyasa Sai Brigisha , Sharma Aditi , Singh Vijendra 
Published: December 2024

Introduction:
Recently Centre for Disease Control recommends RSV vaccine for all adults ≥ 75 years and adults between 60-74 years at increased risk of severe RSV. However, this age restriction might not hold true for certain specific groups of population like patients with hematological malignancies who express dysregulated immune system. So, this study aims to analyze the outcomes of hospitalizations with RSV infection in patients with hematological malignancies with the intent to broaden the usage of RSV vaccine in this subgroup.
Material and Methods:
In this retrospective study, utilizing the National Inpatient Sample database of 2018 to 2021, we identified 9920 admissions for RSV in the United States. Inclusion criteria were age ≥18 years and ICD-10 code J12.1; J20.5; J21.0; B97.4, listed as the principal diagnosis. Acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), chronic myeloid leukemia (CML), Hodgkin's lymphoma (HL), multiple myeloma (MM), and non-Hodgkin's lymphoma (NHL) were then identified by using appropriate ICD-10 codes. Descriptive analysis was performed and the mortality rate was compared between ages &lt;60 and ≥ 60. Age, sex, and race adjusted odds ratio (aOR) and 95% confidence intervals (CI) for mortality were also estimated for each cancer using multivariable logistic regression. All analyses were performed after applying weights to produce national estimates.
Results:
Out of 735 hospitalizations for RSV with hematological malignancy, 6.2% had ALL, 19.1% had AML, 11.7% had CLL, 2.8% had CML, 2.04% had HL, 37.4% had MM, and 23.2% had NHL. At baseline, there were statistically significant differences in mean age, gender, length of hospital stay, and mortality in those with and without underlying hematological malignancy. Overall, the crude mortality rate with RSV was higher in admissions with hematological malignancies compared to those without (10% vs. 6.4%; P&lt;0.001). When hematological cancers were stratified according to age (&lt; 60 years vs. &gt; 60 years), there was no difference in mortality rates (9.26% vs. 10.23%, p=0.704). Surprisingly, when looking at specific subgroups, NHL patients under 60 years of age had higher mortality rates compared to those over 60 years of age (18.60% vs. 7.87%; p=0.046), a finding not seen in ALL (P=0.096), AML (P=0.854), CLL (P=0.243), CML (P=0.251), and MM (P=0.369). On multivariable logistic regression, adjusting for age, sex, and race, having an underlying hematological malignancy increased the odds of death in RSV (1.63; 95% CI: 1.26-2.12; P&lt;0.001). Specifically, having AML had the highest odds of mortality (2.55; 95% CI: 1.52-4.3; P&lt;0.001) and so did having non-Hodgkin's lymphoma (1.73; 95% CI: 1.06-2.83; P=0.028). The adjusted length of stay was also significantly longer in patients with hematological malignancies in general (mean difference 3.92 days; 95% CI: 2.76-5.08; P&lt;0.001) and most pronounced in patients with AML in particular (9.52 days; 95% CI: 6.82-12.82; P&lt;0.001).
Conclusion:
In conclusion, RSV infection significantly increases mortality and hospital stay lengths in patients with hematological malignancies, especially in those with AML and younger NHL patients. These findings highlight the need for targeted interventions, including vaccination, to improve outcomes in this high-risk group. Prospective studies are needed to further explore these associations and develop effective prevention strategies.