 The study examined the prevalent human adenovirus, HADV, types causing acute respiratory tract infections, ARTIs, and outbreaks in China between 2009 and 2020. It found that HADV-3 and HADV-7 were the most common types detected in both outbreaks and etiologic surveillance studies. In addition, HADV-55 was identified as the leading cause of outbreaks in military camps and schools, while HADV-7 was the most common type in outbreaks in general. Furthermore, the study showed that HADV-55 infections tended to develop into pneumonia with worse prognoses in children under five years old. This study provides valuable insight into the epidemiology and clinical features of HADV infections in China, which can help inform future surveillance and control efforts. This article was authored by Meichan Liu, Changsu, Tingting Li, and others.