Mortality and Morbidity of Human Metapneumovirus Infection in the Pre-COVID-19 Era: The Value of the Charlson Comorbidity Index on Outcome Prediction

Human metapneumovirus (HMPV) is an important cause of seasonal respiratory tract infections, mainly in children and immunocompromised adults. The use of the Charlson Comorbidity Index (CCI) to predict outcomes in hospitalized patients has been validated in several settings. This study aims to describe the clinical characteristics of adult patients with HMPV infection and evaluate the value of the CCI in predicting outcomes in patients with acute HMPV infections requiring hospitalization. This is a single-center case-series study of hospitalized patients with HMPV infection in 2017. Twenty-two adult patients with a mean age of 65 years were reviewed. The mean CCI was 4.6±2.6. The overall mortality was 22%. An abnormal chest X-ray (CXR) was reported in 15 patients. CCI was not different between survivors and non-survivors. Non-survivors were more likely to have abnormal CXR and a higher fever at the time of diagnosis, required mechanical ventilation, or had other concomitant infections. The average CCI was 4.5, which was not significantly different between survivors and non-survivors. The mortality rate was elevated by 22% and was likely associated with admission to the ICU as well as the presence of another concomitant infection.