Early Hemogram-Derived Inflammatory Indices Do Not Independently Predict Hospital Stay in Children with Human Bocavirus Detected by Polymerase Chain Reaction

Background/Objectives: Human bocavirus (HBoV) is frequently detected by polymerase chain reaction (PCR) in respiratory samples from children with acute respiratory tract disease, but prolonged viral DNA persistence and frequent co-detection complicate interpretation of its clinical significance. We evaluated whether early hemogram-derived inflammatory indices are associated with clinical outcomes in hospitalized children with PCR-detected HBoV. Methods: This single-center retrospective cohort included 170 hospitalized children aged 1 month to 18 years with HBoV detected by PCR in nasopharyngeal samples between July 2022 and June 2025. Data obtained within the first 24 h of hospitalization were analyzed. Systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and neutrophil percentage-to-albumin ratio (NPAR) were calculated. Associations with clinical outcomes were assessed using correlation analyses, and multivariable generalized linear modeling was used to evaluate factors associated with length of hospital stay. Results: Median age was 18 months (IQR, 11–33), and microbiological co-detection was present in 60.4%. Oxygen therapy was required in 82.8%, high-flow nasal cannula support in 22.0%, and PICU admission in 5.4%. All four indices were inversely correlated with length of hospital stay and blood gas bicarbonate levels. However, none independently predicted length of stay after adjustment. Neurological disease, neutrophil percentage, and tachycardia remained independently associated with length of stay; neurological disease was associated with a 1.56-fold longer expected hospitalization, whereas higher neutrophil percentage and tachycardia were associated with shorter expected hospitalization. Conclusions: Early hemogram-derived inflammatory indices were associated with clinical course but did not independently predict hospitalization duration in children with PCR-detected HBoV. Their prognostic value should be interpreted cautiously, particularly when length of stay is used as a process-sensitive outcome, and the observed associations should not be considered HBoV-specific.