Associated factors of microorganisms causing lower respiratory tract infections in children hospitalized between 2019 and 2022 in a private hospital in Lima, Perú

Introduction: Lower respiratory tract infection is the leading cause of childhood death wordwide. Etiological agents showed seasonal, geographic, and pandemic-related variation. Objective: To determine the clinical manifestations of respiratory pathogens in children hospitalized due to lower respiratory tract infection before, during, and after the pandemic in a private hospital in Lima, Perú. Materials and methods: This is a retrospective cohort study of patients under 13 years of age hospitalized with lower respiratory tract infection. Two multiplex polymerase chain reaction (PCR) tests, CLART Fast PneumoVir™ and PneumoCLART Bacteria®, were used to identify pathogens. We identified factors associated with prolonged hospitalization based on general characteristics and the presence of pathogens. Results: A total of 612 patient records were analyzed. The average age was 2.89 years. Respiratory syncytial virus was identified in 33.66% (206/612) of cases, influenza A in 26.31% (161/612), and Haemophilus sp. in 19.28% (118/612). Before the COVID-19 pandemic, 48.9% of patients had a viral etiologic agent, and 87.78% (115/131) had one after the pandemic. During the pre-pandemic period, 17.34% (77/444) of patients had more than one microorganism, with frequent coinfections of respiratory syncytial virus with Haemophilus sp. (10.78%) (66/612) and respiratory syncytial virus with influenza A virus (8.82%) (54/612). Additionally, the identification of respiratory syncytial virus was associated with prolonged hospital stays of more than 6 days (p = 0.005). Conclusions: This study found that viral etiologic agents were predominant before and after the pandemic. Furthermore, coinfections between bacteria and viruses were frequent. The respiratory syncytial virus was the most common and was associated with coinfections and prolonged hospital stays.