OBJECTIVES: Respiratory syncytial virus (RSV) is increasingly a recognized cause of respiratory infection among adults. This study estimated costs of RSV hospitalization for adults ≥18 years in Spain and descriptively contrasted this to influenza hospitalization costs between 2016–2019.

METHODS: A retrospective observational study was conducted using a national hospital discharge database that reports >90% of admissions. RSV and influenza hospitalizations were identified using ICD-10-specific codes. Mean hospitalization costs (€, 2022) were stratified by age and risk groups. Total annual RSV costs were estimated by combining RSV-reported and RSV-attributed hospitalization rates previously reported in the same population and the current hospitalization costs.

RESULTS: From 2016–2019, a total of 11,662 adults were admitted to hospital with RSV. The mean hospital length of stay (LoS) ranged from 5-12 days with higher LoS in higher-risk groups, regardless of age. Among adults with risk factors (moderate/high-risk), 2–15% required intensive care unit admission. Mean costs per RSV hospitalization event ranged from €3,435–5,246 for 18–49 years, €3,364–5,112 for 50–59 years, €3,195–5,549 for 60–69 years, €2,942–5,226 for 70–79 years, and €2,928–3,921 for ≥80 years. Costs were higher in the moderate and high-risk groups in each age category. Influenza costs ranged from €2,271–6,145 depending on age and risk. RSV mean costs were higher (22-34%) than influenza in low-risk groups of all ages, and in high-risk groups aged 70-79 years (14%), lower (21%) in high-risk groups aged 50–59 years, and generally comparable (<10%) in the rest. Total annual hospitalization costs for RSV were estimated at M(million) €12.1 with reported incidence and M€194.3 with RSV-attributed incidence vs influenza M€83.2.

CONCLUSIONS: In adults, RSV has a significant economic burden to the Spanish National Healthcare System. If corrected for under-ascertainment, RSV likely has an economic burden greater than influenza.