Disease Severity and Viral Codetection in Acute Lower Respiratory Tract Infection

Background: It is unclear whether codetections of viruses in respiratory infections are associated with worse outcomes. We aimed to establish the association between viral codetections and severity in children under 5 years of age hospitalized with suspected viral pneumonia. Methods: We designed a case-control study. The population comprised children hospitalized at a tertiary-level institution between September 2019 and June 2022 with clinical suspicion of pneumonia and detection of at least 1 respiratory virus by nested Multiplex polymerase chain reaction (FilmArray Respiratory Panel, Biomerieux). The cases were children between 1 and 60 months of age who met the severity criteria: complicated pneumonia, intrapulmonary complications, vasoactive requirement or ventilatory support or death. Controls were patients who did not meet these criteria. We performed multivariate analysis using binary logistic regression models to calculate adjusted ORs (ORa) for relevant variables and potential confounders. Results: We included 561 patients; 224 (39.9%) were infants, of whom 175 patients (31.2%) required intensive care and 1 died. Codetection was found in 223 children (39.8%). In the multivariate analysis, being younger than 1 year [ORa = 2.8; 95% confidence interval (CI): 1.8–4.5], and having a prior bronchiolitis (ORa = 3.6; 95% CI: 1.4–8.9), but not codetections (ORa = 1.4; 95% CI: 0.9–2.0), were independently associated with a greater severity. However, codetection was the only associated variable with worse severity in the subgroup of infants (ORa = 2.7, 95% CI: 1.1–6.8). Conclusions: The detection of 2 or more viruses in children <1 year of age with suspected viral pneumonia is associated with more severe disease.