Impact of SARS-CoV-2 variants and demographic factors on COVID-19 severity in pediatric patients
Barter, TT; Ostrow, D; Weaver, C; et al., BMC Infectious Diseases, July 2026
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Short Summary
Researchers wanted to know why some children get sicker than others when they get COVID-19. Different versions (variants) of SARS-CoV-2, the virus that causes COVID-19, can affect children differently. A child’s age, sex, race, or ethnicity (demographic factors) may also play a role in determining which COVID symptoms they experience—and how burdensome (severe) those symptoms become.
Researchers reviewed electronic health record (EHR) data from a large group of children (ages 0–25) who visited Children’s Hospital Los Angeles between 2020 and 2024 and tested positive for SARS-CoV-2. Next, researchers analyzed biosamples to identify which viral variant was responsible for causing a child's COVID-19. Researchers then compared COVID-19 severity between different viral variants and demographic factors.
Researchers found that COVID-19 caused by the Omicron variant was more likely to be associated with moderate or severe COVID-19 in children compared to COVID-19 caused by earlier variants, like Delta or Epsilon. This finding contrasts with studies in adults that generally found that Omicron infections were milder. The authors also noted that Long COVID cases did not appear to cluster around specific variant periods, suggesting that children’s risk of developing Long COVID may not be tied to a particular variant in the same way it may be in adults.
In terms of demographic factors, researchers found that children who were male had an increased likelihood of experiencing moderate or severe COVID-19 compared with females. Younger children (0–5 years) showed an increased likelihood of experiencing moderate or severe COVID-19 compared to older children. Researchers also found that COVID-19 severity can differ across racial and ethnic groups. For example, Hispanic/Latino and White children included in the study were less likely to develop severe COVID-19 as their age increased, while the data showed Asian children showed a slight increase in severe illness at older ages.
These findings suggest that age, race and ethnicity, and viral variants may interact in complex ways to influence how sick a child becomes with COVID-19. Understanding how viral variants interact with children’s demographic characteristics could inform how health providers care for children who may be at higher risk of experiencing severe COVID-19 or Long COVID.
This summary was prepared by the RECOVER Initiative.
Publication Details
DOI: 10.1186/s12879-026-13987-z
Abstract
Background: Factors that influence pediatric COVID-19 severity remain incompletely understood, particularly related to the impact of viral and host factors. Understanding the factors contributing to the severity of presentation can impact clinical approaches and management. This study examined the associations between SARS-CoV-2 variants, demographic factors, and COVID-19 severity in a large diverse pediatric population.
Methods: We conducted a retrospective cohort study at a large freestanding Children's Hospital (Children's Hospital Los Angeles) from March 2020 through April 2024, including 14,292 patients aged 0-25 years who tested positive for SARS-CoV-2. Viral variants were determined by whole genome sequencing in 6,939 patients (48.6%). COVID-19 severity was classified as mild, moderate, or severe based on hospitalization requirements and need for respiratory support following the World Health Organization criteria. Disease severity comparisons were made between different viral variants and demographic factors using multinomial logistic regression.
Results: Among 14,292 patients, 53.8% were male with median age 5.2 years. Racial/ethnic distribution was 63.0% Hispanic/Latino, 21.4% White, 9.3% African American, and 6.3% Asian. Compared with pre-Omicron variants, Omicron was associated with increased odds of moderate (odds ratio [OR], 2.85; 95% CI, 2.31-3.52; P < 0.001) and severe disease (OR, 3.95; 95% CI, 3.01-5.18; P < 0.001). White patients had lower odds of moderate (OR, 0.81; 95% CI, 0.67-0.98) and severe disease (OR, 0.82; 95% CI, 0.64-1.05) compared with non-White patients. Age-race interactions were significant, with different severity patterns across racial groups as age increased.
Conclusions: Our findings suggest that both viral variants and host demographic factors contribute meaningfully to pediatric COVID-19 severity. Understanding these interactions would support a more tailored approach to pediatric COVID-19 that considers the impact of viral variants and host demographic factors.
Authors
Thomas T Barter, Dejerianne Ostrow, Carly Weaver, John C Wood, David Warburton, Matthew Deardorff, Xiaowu Gai, Jennifer Dien Bard, Sindhu Mohandas
Keywords
COVID-19 Severity; Genome sequencing; Health disparities; Patient demographics; Pediatrics; SARS-CoV-2; Viral variants