Background: Adenovirus is responsible for 2–7% of childhood viral respiratory infections, 5–11% of viral pneumonia and bronchiolitis. Most are self-limited but may cause severe respiratory infection.

Objectives: To describe adenovirus respiratory infection in immunocompetent children in a pediatric intensive care unit (PICU).

Methods: Children with adenovirus respiratory infection in our PICU from 2007 to 2016 were included. Data were retrospectively retrieved, including background, clinical manifestation, and treatment. Adenovirus was diagnosed by polymerase chain reaction, immune fluorescence, or both.

Results: Of 9397 samples, 956 were positive for adenovirus in children hospitalized during the study period. In total, 49 patients (aged 2 months–11.5 years) were admitted to our PICU, five were immunocompromised and excluded from the study, 19/44 (43%) were referred from other hospitals. Twenty-eight (64%) had underlying conditions, 66% had fever and cough, 11% had conjunctivitis, and 34% received antibiotics before admission. White blood cell counts ranged from 790 to 34,300 (mean 14,600) and 36% had counts above 15,000. Chest X-ray was consistent with viral infection in 77% of patients and normal in three (13.6%). Viral co-infection was found in 9 patients, 7 had presumed bacterial super-infection, and 27 (61.4%) needed mechanical ventilation. Two patients received cidofovir, 33 (75%) steroids, and 37 (84 %) antibiotics. Four patients died.

Conclusions: Adenovirus respiratory infection may cause severe disease necessitating PICU admission and mechanical ventilation, mostly in patients with underlying conditions. Many patients received steroids and antibiotics, which may be unnecessary. Mortality was 9%, mainly among young infants and those with underlying conditions.