Burden of viral respiratory infections in the pediatric intensive care unit: age, virus distribution, and the impact of the COVID-19 pandemic.

Abstract

Though usually self-limiting, viral respiratory infections can escalate to severe cases requiring admission to a pediatric intensive care unit (PICU). This study aims to examine the proportional incidence, affected age ranges, viral pathogens involved, associated severity measures, and the impact of the COVID-19 pandemic on their incidence and virus distribution. This retrospective cohort study conducted in a tertiary care center (2011-2021) reviewed all pediatric patients admitted to PICU with laboratory-confirmed viral respiratory infection. The study included 312 patients, comprising 5.5% of all PICU admissions; 45% were males; 52% had underlying conditions. The median age was 1.1 (IQR 0.3-2.8) years; 18% were born prematurely. The most common viruses were respiratory syncytial virus (35%), adenovirus (26%), influenza (10%), parainfluenza (11%), and human metapneumovirus (11%). All viruses displayed a seasonal pattern, except year-round occurrence in adenovirus. The seasonality pattern was disrupted by COVID-19 pandemic-related restrictions. Mechanical ventilation was required for 46% of patients; 27% required other non-invasive respiratory support. Thirty-day mortality was documented in 18 (5.8%) patients. Underlying conditions, particularly immunosuppression, neuromuscular diseases, and genetic/metabolic syndromes, were associated with increased mortality (p = 0.001, 0.006, and 0.001, respectively). Adenovirus was also linked to higher mortality (p = 0.04), hMPV to prolonged ventilation (p = 0.004) and prolonged PICU stay (p = 0.009), and SARS-CoV-2 to extended ventilation (p = 0.04). During COVID-19, patients were older (p = 0.001), RSV cases decreased (p = 0.006), ventilation duration increased (p = 0.03), and cardiologic complications rose (p = 0.02). No influenza A or B cases appeared post-pandemic.

Conclusion: Viral respiratory infections can lead to severe complications. Their high prevalence in infants and young children highlights the need to extend vaccination age ranges for vaccine-preventable viral infections, monitor uptake in at-risk children, and implement public health interventions in daycare settings.

What is known: • Viral respiratory infections in children are a significant cause of illness and mortality.

What is new: • Severe infections in children beyond current vaccine eligibility suggest the need to expand vaccination to broader age groups. • SARS-CoV-2 dominance during the COVID-19 pandemic altered disease characteristics of respiratory infections.