There is no study available about HPV 6/11 infection in the lower airway of healthy neonate/children. In some studies of adults, the prevalence of HPV 6/11 in larynx or vocal cord of patients without recurrent respiratory papillomatosis ranged between 19~25%. In contrast, several studies had specimen taken from the non-disease lower airway (trachea, vocal cord) and/or larynx of patients with JORRP. Except for the almost 100% presence of HPV 6/11 DNA in the diseased site, 38~60% of specimens taken from non-disease site were also positive for the viral DNA, showing that latent infection is not infrequent in normal airway, and may later cause active disease by mechanism still unknown to date.