Characteristics and Risk Factors Associated With Hospitalization and Severe Disease in Patients Aged ≥ 60 Years With...

Human metapneumovirus (hMPV) is a respiratory pathogen often underestimated in the elderly. Although studies suggest it causes around 10% of respiratory hospitalizations in the United States, national and local data remain scarce. This study aimed to describe patients hospitalized with hMPV and identify risk factors for hospitalization and severe disease.

A retrospective study included adults aged ≥ 60 years diagnosed with hMPV infection in two hospitals in Valladolid, Spain, during three consecutive seasons (2021-2024). Data on demographics, comorbidities, clinical presentation, laboratory results and severity parameters were collected. Severe disease was defined as hospital stay ≥ 11 days, ICU admission, need for mechanical ventilation, readmission within 90 days or in-hospital death.

Among 703 hMPV-confirmed cases, 608 required hospitalization, following a clear seasonal epidemic pattern (November-March). The hospitalization rate was 123.2 per 100,000 > 60 years old inhabitants (95% CI: 113.6-133.4), representing 20.5% of respiratory virus detections. Mean hospital stay was 10.5 days; 6.4% of the patients were admitted to ICU, 3.3% required mechanical ventilation, 6.9% died, and 14.0% were readmitted within 90 days. Advanced age (≥ 75 years) increased hospitalization risk threefold to fivefold compared to people between 60 and 74 years old. Co-infections, particularly bacterial, and living in nursing homes were also associated with a 1.5-2.7 fold higher risk of severe disease and hospitalization.

hMPV infections pose a significant health burden among the elderly. The findings underscore the need for greater awareness, surveillance, and development of preventive strategies, including vaccination, against hMPV in older adults.