Background Limited data from Singapore indicates that respiratory virus infection (RVI) burden is high and comparable to other settings in temperate countries. Acute lower respiratory infections from RVIs are important contributors to mortality in children <5 years of age, with most deaths occurring in the first year of life.

Objectives This study aims to describe the burden and epidemiology of RVI-associated mortality among children admitted to the paediatric intensive care unit (PICU).

Methods We performed a linkage analysis of PICU mortality database with laboratory confirmed RVI database of patients <18 years old from 2010 to 2019. RVI-associated mortality was defined as cases with a laboratory confirmed RVI from any respiratory sample within 14 days prior to the certified date of death.

Results Over the 10-year period, there were 339 (5.6%) deaths out of 6101 admissions to the PICU. 67 (19.8%) out of a total of 339 deaths were associated with RVIs. Patients with RVI-associated mortality had a median age of 3 years (Q1 - Q3, 0 - 8). The majority were male (n=38, 56.7%). 23 (34.3%) of the patients were born preterm and 42 (62.7%) had co-morbid conditions. Influenza (22.7%), adenovirus (17.3%), respiratory syncytial virus (RSV) (16%) and rhinovirus (16%) were the most common viruses isolated. Eight patients (11.9%) had RVI coinfection. The most common documented cause of death in this cohort of RVI-associated mortalities was viral and/or secondary bacterial infections (76.1%) followed by cardiovascular causes (7.5%). The median hospital length of stay prior to death was 8 days (Q1 - Q3, 3 - 15).

Conclusions The burden of RVI-associated mortality is high among critically ill children. These data on the burden and age-specific distribution of RVI-associated mortality in children are critical in informing infection prevention practices among high-risk groups and immunization public health policies for RVIs. Efforts to improve influenza vaccination coverage especially in children with comorbidities or history of prematurity could have a significant impact in reducing this burden.