Coronavirus disease-2019 (COVID-19) is a respiratory system disease caused by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). In cases with COVID-19 pneumonia, other respiratory viral agents may be simultaneously present. An 11-monthold male patient diagnosed with hydrocephalus, epilepsy and mental-motor retardation was referred to our hospital with fever, cough, and vomiting. The nasopharyngeal swab sample was positive for SARS-CoV-2 and human metapneumovirus. The patient's respiratory distress increased on the third day of the follow-up, and hydroxychloroquine sulfate was added to his treatment. On day 11 of follow-up, based on the deteriorating general condition of the patient and increased acute phase reactants, sepsis secondary to nosocomial infection was considered. Acinetobacter baumannii growth was seen in the blood culture. After antibiotic treatment, the patient's clinical condition improved. Our findings support the idea that COVID-19 can be severe in young children when it coexists with viruses that cause other respiratory tract infections.