Clinical Features of Human Metapneumovirus-Associated Community-acquired Pneumonia Hospitalizations.

BACKGROUND: Human metapneumovirus (HMPV) is a leading cause of respiratory tract infections. Few studies have compared the clinical characteristics and severity of HMPV-associated pneumonia with other pathogens.

METHODS: Active, population-based surveillance was previously conducted for radiographically confirmed, community-acquired pneumonia hospitalizations among children and adults in 8 United States hospitals. Clinical data and specimens for pathogen detection were systematically collected. We described clinical features of all HMPV-associated pneumonia and, after excluding codetections with other pathogen types, we compared features of HMPV-associated pneumonia with other viral, atypical, and bacterial pneumonia and modeled the severity (mild, moderate, and severe) and length of stay using multivariable proportional odds regression.

RESULTS: HMPV was detected in 298/2358 (12.6%) children and 88/2320 (3.8%) adults hospitalized with pneumonia and was commonly codetected with other pathogens (125/298 [42%] children and 21/88 [24%] adults). Fever and cough were the most common presenting symptoms of HMPV-associated pneumonia and were also common symptoms of other pathogens. After excluding codetections in children (n = 1778), compared to HMPV (reference), bacterial pneumonia exhibited increased severity (odds ratio [OR], 3.66; 95% confidence interval [CI], 1.43-9.40), respiratory syncytial virus (RSV; OR, 0.76; 95% CI, .59-.99) and atypical (OR, 0.39; 95% CI, .19-.81) infections exhibited decreased severity, and other viral pneumonia exhibited similar severity (OR, 0.88; 95% CI, .55-1.39). In adults (n = 2145), bacterial (OR, 3.74; 95% CI, 1.87-7.47) and RSV pneumonia (OR, 1.82; 95% CI, 1.32-2.50) were more severe than HMPV (reference), but all other pathogens had similar severity.

CONCLUSIONS: Clinical features did not reliably distinguish HMPV-associated pneumonia from other pathogens. HMPV-associated pneumonia was less severe than bacterial and adult RSV pneumonia, but was otherwise as or more severe than other common pathogens.