Bastien et al. [8] suggested that risk factors for severe HBoV infection appear to be similar to those for RSV infection (prematurity, congenital heart disease, and asthma). Thirty percent (26/93) of the HBoV-positive patients had underlying conditions such as heart disease, asthma, allergy, preterm birth, and a history of convulsions; most of these patients (80.8%) showed a low-viral-load. Persistent HBoV shedding for more than 1 month is observed in both respiratory and fecal specimens obtained from patients with significant underlying diseases [19] . Although these finding were not fully understood, it is postulated to be a result of underlying immunosuppression [19] .