Clinical characteristics, pathogen detection, and severity markers among children with acute respiratory infections during the COVID-19 restriction period: a retrospective hospital-based study.

BACKGROUND: The epidemiology of pediatric acute respiratory infections (ARIs) changed substantially during the COVID-19 (coronavirus disease 2019) pandemic, largely because of school closures, masking, reduced travel, and other non-pharmaceutical interventions (NPIs). However, hospital-based data from the restriction period remain useful for describing pathogen detection patterns, clinical severity, and markers of adverse clinical course.

METHODS: We conducted a retrospective hospital-based study of 62 children aged <18 years who were evaluated for ARI symptoms and underwent real-time fluorescent quantitative nucleic acid testing for common respiratory pathogens, including respiratory viruses and Mycoplasma pneumoniae. Demographic, clinical, laboratory, treatment, severity, and outcome variables were extracted from medical records. Continuous variables were summarized using medians and ranges, and group comparisons used non-parametric tests. Given the small sample size and sparse severe-outcome events, the study was not powered to detect small effect sizes, and regression findings were interpreted conservatively as hypothesis-generating rather than confirmatory.

RESULTS: The median age was 9 years (range, 1-17), and 33 patients (53.2%) were female. Most children had mild disease (37/62, 59.7%); 19 (30.6%) had moderate disease and 6 (9.7%) had severe disease. Intensive care unit (ICU) admission was recorded in 6 patients (9.7%), and mechanical ventilatory or noninvasive respiratory support in 9 (14.5%). Fever (43.5%) and cough (22.6%) were the most frequent presenting symptoms. Median oxygen saturation was 94.7% (range, 87.2-97.8). Respiratory virus detection was documented in 15 children (24.2%). Human rhinovirus was detected in 15 children (24.2%), human bocavirus in 9 (14.5%), and Mycoplasma pneumoniae in 10 (16.1%); co-detection was recorded in 14 children (22.6%). Lower SpO2 and longer symptom duration differed significantly across severity categories (both p < 0.001). In exploratory logistic regression, each additional day of symptoms was associated with higher odds of hospital admission/continued inpatient management [odds ratio [OR], 1.4; 95% confidence interval [CI], 1.03-1.93; p = 0.022]. Sex was not significantly associated with clinical severity or laboratory parameters.

CONCLUSIONS: In this small hospital-based pediatric ARI cohort during the COVID-19 restriction period, severe disease was uncommon, and oxygen saturation and symptom duration were the most clinically coherent markers of greater severity. The observed pathogen detection pattern is compatible with pandemic-era disruption of respiratory pathogen circulation, but causal conclusions about NPIs require larger denominator-based studies with pre-pandemic and post-restriction comparison groups.