Authors of a new study of more than 31 000 hospitalized children with SARS-CoV-2 infection found that disease severity varied by age over the course of the COVID-19 pandemic.
Findings published online August 21, 2023, in JAMA Pediatrics showed that intensive care unit (ICU) admissions for COVID-19 decreased over the course of the pandemic in all age groups—which ranged from less than 6 months to less than 18 years of age—but ventilatory and oxygen support in children younger than 5 years of age did not.
“These findings highlight the importance of considering different pediatric age groups when assessing disease severity in SARS-CoV-2,” wrote first author Yanshan Zhu, MMed, PhD student, University of Queensland, Australia, and colleagues.
Zhu and colleagues conducted the current multicenter retrospective cohort study in order to assess the impact of SARS-CoV-2 variants of concern (VOC) on the severity of COVID-19 in hospitalized children starting from the beginning of the pandemic in January of 2020.
“In adults, the emergence of VOCs, in particular the Omicron variant, has been associated with altered disease severity relative to the ancestral virus,” said researchers. “The VOCs, particularly Omicron, in severe COVID-19 among children remains less well defined…studies across the age spectrum in children are urgently needed to inform public health policies.”
Investigators examined clinical data of 31 785 hospitalized pediatric patients in the United Kingdom, Portugal, Italy, Switzerland, South Africa, Brazil, US, Thailand, and Australia between January 1, 2020, and March 31, 2022. They then divided the data into 3 different time frames, categorized by the dominant strain or strains:
Zhu and colleagues defined age categories as younger than 6 months, 6 months to less than 5 years of age, and 5 years to less than 18 years of age, according to the study.
“The primary outcome was disease severity as defined by the need for ICU admission, ventilatory support, or oxygen therapy,” noted Zhu and coauthors.
Among the 31 785 hospitalized children included in the study, the median age was 4 years and 52.3% (n=16 639) were boys.
Results showed a decrease in risk ratios (RRs) between T1 (ancestral virus) and T3 (Omicron) time periods in ICU admissions (RR 0.39, 95% CI 0.32-0.48), ventilatory support (RR 0.37, 95% CI 0.27-0.51), and oxygen therapy (RR 0.47, 95% CI 0.32-0.70) among children aged 5 to 18 years.
In children aged less than 5 years, across the 3 time periods, investigators observed a reduction in ICU admission (T3 vs T1: RR 0.56; 95% CI 0.42-0.75 [younger than 6 months]; RR 0.61; 95% CI 0.47-0.79 [6 months to less than 5 years]), but not in ventilatory support or oxygen therapy.
These results were consistent when data were restricted to unvaccinated children, noted researchers.
“These study data can inform mechanistic and intervention research, as well as public health policy, which must be aware of the importance of considering different pediatric age groups when assessing the severity of disease in future SARS-CoV-2 waves,” wrote Zhu et al.
Reference: Zhu Y, Almeida FJ, Baillie JK, et al. International pediatric COVID-19 severity over the course of the pandemic. JAMA Pediatr. Published online August 21, 2023. Accessed August 24, 2023. doi:10.1001/jamapediatrics.2023.3117