Epidemiology of Viral Infections in Neonatal Intensive Care Units in Western Australia: A Retrospective Study From 2016 to 2021 Including the COVID-19 Pandemic.

Background: Viral infections are associated with significant morbidity and mortality in neonates. The COVID-19 pandemic led to changes in viral epidemiology in Western Australia. The impact on patients in neonatal intensive care is uncertain.

Methods: A retrospective cohort study of all infants admitted to King Edward Memorial Hospital and Perth Children's Hospital Neonatal Intensive Care Units with laboratory-confirmed viral infections between January 2016 and June 2021 was performed. Demographic, clinical, polymerase chain reaction virus type, management, and outcomes data were collected. Groups were compared by χ-2 and comparison of means as appropriate. P values <0.05 were considered significant.

Results: A total of 14,935 infants were admitted during the study period. There were 267 positive polymerase chain reaction tests in 140 infants (0.8%). Viruses detected included rhinovirus (60/140, 43%), respiratory syncytial virus (48/140, 34%), enterovirus (15/140, 11%) and cytomegalovirus (8/140, 6%). Respiratory viral infections (RVIs) were more common than nonrespiratory viral infections (110/140 [79%] vs. 30/140 [21%]; P < 0.001). A majority of RVI and nonrespiratory viral infections were community-acquired (75/110 [68%] and 19/30 [63%], respectively) and in preterm infants (75/110 [68%] and 19/30 [63%], respectively). A higher proportion of infants with NRVIs compared to RVIs had long-term sequelae (13/30 [43%] vs. 17/110 [15%]; P < 0.001). RVIs decreased during COVID-19 in WA but remained similar for NRVIs.

Conclusions: The incidence of viral infection in our study was 0.8% of all admissions. Respiratory viruses were most common, more likely to be community-acquired, and in infants born preterm. COVID-19 and community control measures had an impact on NICU viral incidence.