Disease Burden of RSV Infection in Adult Patients in Comparison to Influenza Virus Infection

Abstract

Respiratory Syncytial Virus (RSV) is well known for its impact on children, but its burden in adults remains underexplored, partly due to limited PCR testing before the COVID-19 pandemic. In this study, the medical burden of RSV infections in adults was retrospectively investigated using 6-year longitudinal data from a university hospital in North Rhine-Westphalia, Germany. Outcomes of 380 PCR-confirmed RSV cases were compared with 1088 influenza A/B cases from 2018 to 2023, stratified by age groups ( < 60 and ≥ 60 years). Among RSV cases, 59.7% required hospitalization, of which 22.9% needed oxygen supply. In the whole group hospitalization rates were comparable between RSV and influenza cases, but oxygen supply was more frequent in influenza infections. However, in patients aged ≥ 60 years, no significant differences were observed in hospitalization, oxygen supply, or fatal outcomes between RSV and influenza, indicating a comparable disease burden for both viruses in this group. These findings highlight the significant clinical impact of RSV in adults, particularly those aged ≥ 60 years, paralleling that of influenza. Given influenza's established pathogenic reputation, this underscores the importance of targeted vaccination strategies against RSV, especially for high-risk age groups.

Keywords: RSV; clinical study; influenza virus; respiratory syncytial virus; vaccine.

Figure 1

Characteristics of the University Medicine Essen (UME) Respiratory Syncytial virus (RSV) or Influenza A/B virus (IAV/IBV) positive cohort. (A) Summary of inclusion criteria for the retrospective analysis. (B) Main characteristics of the cohort, depicted are number of patients and distribution of age, subdivided in male and female (numbers (n) and percentages), as well for age (median, minimal (min) and maximal (max) values in years). (C) Course of RSV (purple) and IAV/IBV (turquoise) infection waves over the time period 2018 until mid‐2024 in calendar weeks. Depicted are the number of positive tested cases. Both, first and second lockdown caused by SARS‐CoV‐2 are highlighted (greenish boxes).

Figure 2

Patient characteristics. Characteristics of patients tested positive by PCR for RSV (A) or IAV/IBV (B). Shown are the proportion of hospitalized patients, the outcome, oxygen supply status, and gender and intensive care unit (ICU) admission rates in percentage.

Figure 3

Age distribution in the cohort within two groups, younger than 60 years (dark green) and 60 years and older (light green). (A and B) Percentage of in‐ and outpatients in both age groups are shown for RSV‐infected patients (A) and IAV/IBV infected patients (B). (C and D) Proportion of males and females, as well as number of patients that needed oxygen supply, were admitted to ICU or died are presented for both age groups in percentages. RSV‐infected patients in (C) and IAV/IBV‐infected cohort in (D).

Figure 4

Comorbidities as possible risk factor of a severe course of RSV infection. (A) Frequency of different comorbidities present in the hospitalized RSV cohort. Shown are percentages for the age group ≥ 60 years (light green) and < 60 years dark green. For reasons of clarity, the percentage frequency is only shown for the age group ≥ 60 years. COPD, chronic obstructive pulmonary disease; CHD, chronic heart disease. (B) Multiple logistic regression analysis showing odds ratio and 95% CI as a forest plot for the probability of requiring oxygen due to a pre‐existing condition. Orange dots indicate statistical significance (p ≤ 0.05). (C) Multiple logistic regression analysis showing odds ratio and 95% CI as a forest plot for the association of a pre‐existing condition and infection type (RSV or IAV/IBV). Orange dots indicate statistical significance (p ≤ 0.05).