OBJECTIVES: To analyse the in-hospital burden of vaccine-preventable respiratory diseases with on-going clinical developments and no vaccination alternatives.

METHODS: Firstly, we reviewed ClinicalTrials.gov to identify respiratory viruses that are experiencing growing clinical research for prevention and without available vaccines. We selected the human metapneumovirus (hMPV) and parainfluenza virus (PIV). For the analysis we used publicly available aggregated retrospective real-world data of in-hospital diagnoses and length-of-stay (LoS) identified through ICD-10 codes from the Spanish National Hospital Discharge Database (RAE-CMBD) and the Institute for the Hospital Remuneration System (InEK) in Germany. Mean cost/patient was available in RAE-CMBD, but not in InEK, therefore we approximated it using the DRGs associated, their weights and the Bundesbasisfallwerte. Data was available for 2016-2021 for Spain and 2019-2022 in Germany.

RESULTS: In Spain, a total number of 872 hospitalized cases with a primary diagnostic of hMPV (549) or PIV (323) was reported in 2021. LoS (5.39/5.49 days) and mean cost/patient (€3,723/€4,070) were similar. In the same year, there were 1,041 hospitalized cases with a primary diagnostic of hMPV (197) or PIV (844) in Germany. The use of resources per patient in-hospital was similar for hMPV and PIV (LoS: 6.34/6.07 days; mean cost €2,074/€2,403). In 2021, hMPV and PIV caused a total hospital spending of 3.3€M in Spain and 2.5€M in Germany. Both infections accumulated a substantial burden in children ≤5 years.

CONCLUSIONS: hMPV and PIV infections caused a substantial burden on hospital resources in 2021 in at least two European countries presenting different healthcare provisioning models.

An increasing trend in hospitalisations was observed in Spain for both viruses between 2016-2021 and the number of hospitalized patients in Germany doubled in 2022, compared to 2021. Increased surveillance and real-world data sharing has the potential to confirm the trends in this analysis and may inform effective resource allocation for prevention.