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COVID infection severity in children under 5 years old before and after Omicron emergence in the US

Lindsey Wang1,2, Nathan A Berger2,3, David C Kaelber4

  • 1Center for Artificial Intelligence in Drug Discovery, Case Western Reserve University School of Medicine, Cleveland, OH, USA.

Medrxiv : the Preprint Server for Health Sciences
|January 19, 2022
PubMed

Insights

The Omicron variant caused less severe COVID-19 outcomes in children under 5 compared to the Delta variant. This study found lower rates of emergency department visits, hospitalizations, and ICU admissions for Omicron infections in young children.

Area of Science:

  • Pediatric infectious diseases
  • Virology
  • Public health

Background:

  • Rising pediatric SARS-CoV-2 infections and hospitalizations post-Omicron emergence.
  • Lack of comparative data on disease severity between Omicron and Delta in US children under 5.

Approach:

  • Retrospective cohort study using electronic health records (EHR) of 79,592 children under 5 with first-time SARS-CoV-2 infection.
  • Compared clinical outcomes between Omicron-predominant and Delta-predominant periods using propensity-score matching.
  • Analyzed emergency department visits, hospitalizations, ICU admissions, and mechanical ventilation use.

Key Points:

  • Omicron infections in children under 5 showed significantly lower risks for severe outcomes compared to Delta infections.
  • Specific risk reductions observed: ED visits (RR: 0.71), hospitalizations (RR: 0.33), ICU admissions (RR: 0.32), and mechanical ventilation (RR: 0.29).
  • No significant difference in severity was found when comparing two Delta-predominant periods.

Conclusions:

  • First-time SARS-CoV-2 infections with the Omicron variant were associated with significantly less severe clinical outcomes in children under 5 compared to the Delta variant.
  • Findings are crucial for understanding pediatric COVID-19 severity and informing public health strategies for young children.
Abstract

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