Severity of COVID-19 Pre- and Post-Omicron Emergence in Pediatric Patients: A Global Systematic Literature Review
Author(s)
Deepa Malhotra, MS MBA1, Moe Hein Kyaw, PhD1, Rajeev Nepal, PhD1, Santiago Lopez, MD1, Daniel Curcio, MD2, Rodrigo Sini, MD3, Pinelopi Nikolopoulou, PhD4, Irini Zografaki, MPH4, Stephen Wiblin, MSc5, Isabelle Whittle, MSc6, Fiona Pearson, PhD6, Sophie Pope, BSc6, Fraser Williams, MSc6.
1Pfizer Inc, New York, NY, USA, 2Pfizer Spain, Madrid, Spain, 3Pfizer Brazil, Sao Paulo, Brazil, 4Pfizer Greece, Athens, Greece, 5Pfizer Australia, Sydney, Australia, 6Adelphi Values PROVE™, Bollington, United Kingdom.
1Pfizer Inc, New York, NY, USA, 2Pfizer Spain, Madrid, Spain, 3Pfizer Brazil, Sao Paulo, Brazil, 4Pfizer Greece, Athens, Greece, 5Pfizer Australia, Sydney, Australia, 6Adelphi Values PROVE™, Bollington, United Kingdom.
OBJECTIVES: This systematic literature review (SLR; PROSPERO ID: CRD42024619193) aimed to understand COVID-19-related severity and medical outcomes in pediatric patients (aged 0-17 years) stratified by SARS-CoV-2 variant.
METHODS: Searches of Medline and Embase were conducted in November 2024, supplemented by conference and citation checks from January 2022-December 2024. Included publications reported acute COVID-19 outcomes indicative of disease severity (e.g., hospital or intensive care unit [ICU] admission, mortality), with associated SARS-CoV-2 variant defined by sequencing or variant predominance. Risk of bias was assessed using JBI critical appraisal tools. Rates of overall hospitalization and mortality were calculated across included studies, stratified into pre- and during Omicron predominance.
RESULTS: The SLR included 45 publications reporting outcomes: 28 (62%) during the Omicron period and 22 (53%) during the pre-Omicron period. Although cumulative risk of hospitalization was slightly lower during Omicron vs. pre-Omicron predominance (0.9% vs. 2.6%), the mean risk was comparable (7.3% [range: 0.90-29.7] vs. 5.9% [range: 0.35-19.4]). Similarly, the mean risks of overall mortality and in-hospital mortality were 0.98% (range: 0-7.1) vs. 1.8% (range: 0-12.9), and 3.0% (range: 0-12.9) vs. 2.5% (range: 0-12.9), respectively. Cumulative overall mortality risk was lower during Omicron vs pre-Omicron predominance (0.1% vs. 0.9%). Five publications stratified outcomes (mortality, ICU admission, organ support) by presence and number or severity of comorbidity, and reported worse outcomes associated with comorbidity (i.e., increased risk of ICU admission, longer duration of hospitalization) regardless of variant period, versus individuals with fewer or less severe comorbidities. None of these studies further stratified outcomes by age group.
CONCLUSIONS: COVID-19 severity has remained comparable among pediatric populations since SARS-CoV-2 emergence in 2020 to 2024. High quality observational research using robust statistical methods is required to better assess potential differences in COVID-19 severity-related outcomes among Omicron subvariants in pediatric patients.
METHODS: Searches of Medline and Embase were conducted in November 2024, supplemented by conference and citation checks from January 2022-December 2024. Included publications reported acute COVID-19 outcomes indicative of disease severity (e.g., hospital or intensive care unit [ICU] admission, mortality), with associated SARS-CoV-2 variant defined by sequencing or variant predominance. Risk of bias was assessed using JBI critical appraisal tools. Rates of overall hospitalization and mortality were calculated across included studies, stratified into pre- and during Omicron predominance.
RESULTS: The SLR included 45 publications reporting outcomes: 28 (62%) during the Omicron period and 22 (53%) during the pre-Omicron period. Although cumulative risk of hospitalization was slightly lower during Omicron vs. pre-Omicron predominance (0.9% vs. 2.6%), the mean risk was comparable (7.3% [range: 0.90-29.7] vs. 5.9% [range: 0.35-19.4]). Similarly, the mean risks of overall mortality and in-hospital mortality were 0.98% (range: 0-7.1) vs. 1.8% (range: 0-12.9), and 3.0% (range: 0-12.9) vs. 2.5% (range: 0-12.9), respectively. Cumulative overall mortality risk was lower during Omicron vs pre-Omicron predominance (0.1% vs. 0.9%). Five publications stratified outcomes (mortality, ICU admission, organ support) by presence and number or severity of comorbidity, and reported worse outcomes associated with comorbidity (i.e., increased risk of ICU admission, longer duration of hospitalization) regardless of variant period, versus individuals with fewer or less severe comorbidities. None of these studies further stratified outcomes by age group.
CONCLUSIONS: COVID-19 severity has remained comparable among pediatric populations since SARS-CoV-2 emergence in 2020 to 2024. High quality observational research using robust statistical methods is required to better assess potential differences in COVID-19 severity-related outcomes among Omicron subvariants in pediatric patients.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
EPH212
Topic
Epidemiology & Public Health
Topic Subcategory
Public Health
Disease
Infectious Disease (non-vaccine), No Additional Disease & Conditions/Specialized Treatment Areas, Pediatrics