A Surge in Seizures and Unconsciousness Among Children Infected with SARS-CoV-2 Omicron Variants Compared to Non-Omicron Variants


The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) omicron variants has ushered in a new chapter in the ongoing COVID-19 pandemic. Initially considered a global health crisis in 2019, COVID-19 has since transitioned from a pandemic to an endemic condition.

Notably, the impact of the virus has been observed to vary across different age groups, with children generally experiencing milder symptoms than adults (1).

However, the landscape of the disease has evolved with the emergence of novel variants, and the SARS-CoV-2 omicron variant, designated as a “variant of concern,” has gained prominence due to its heightened transmissibility.

This study delves into the clinical manifestations of coronavirus disease (COVID-19) caused by SARS-CoV-2 omicron variants specifically in children. The period under scrutiny spans from January 2020 to October 2022, encompassing the evolving phases of the pandemic.

A detailed comparison is made between the clinical features of children infected with SARS-CoV-2 non-omicron variants and those with omicron variants. The objective is to shed light on the distinctive characteristics of the omicron variant in pediatric cases, thereby contributing to a more nuanced understanding of its impact on this vulnerable population.


The trajectory of the COVID-19 pandemic has been punctuated by the emergence of various SARS-CoV-2 variants, each presenting unique challenges to public health. Among these, the omicron variant has garnered attention for its rapid spread and increased infectivity, particularly affecting younger individuals (3). The urgency surrounding the omicron variant has prompted a closer examination of its clinical implications, necessitating focused research on its impact on pediatric populations.

Several studies have noted differences in symptomatology between SARS-CoV-2 variants (2), underscoring the need for variant-specific analyses. While the milder manifestation of COVID-19 in children has been a consistent observation, recent reports have raised concerns about the potential for more severe outcomes associated with the omicron variant in pediatric cases (5–8).

Notably, seizures have been identified in children infected with omicron variants, as documented in various case reports. Despite this, the current understanding of the clinical features in pediatric cases of omicron variant infection remains limited, prompting the need for more comprehensive investigations.

Objectives of the Study

The primary goal of this study is to elucidate the distinctive clinical features of COVID-19 in children caused by SARS-CoV-2 omicron variants. To achieve this, a thorough comparative analysis is conducted between two groups: children infected with SARS-CoV-2 non-omicron variants and those with omicron variants. By meticulously examining the spectrum of clinical presentations, the study aims to provide insights into the unique characteristics of omicron variant infections in pediatric patients.



The study population comprises children diagnosed with COVID-19 who sought medical attention at Tokyo Metropolitan Toshima Hospital between January 2020 and October 2022. This timeframe encapsulates the evolving phases of the pandemic, allowing for a comprehensive analysis of the clinical features associated with both non-omicron and omicron variants.

Comparative Analysis

A total of 214 children with SARS-CoV-2 non-omicron variants and 557 children with omicron variants form the basis for the comparative analysis. The clinical features of these two cohorts are meticulously examined to identify any significant differences in symptomatology.

Outcome Measures

Key outcome measures include the prevalence of symptoms such as fever, sore throat, nausea and/or vomiting, seizures, and disorders of consciousness in both groups. Special attention is directed towards the occurrence of seizures and unconsciousness, with a focus on understanding the nature and distribution of these events.


The preliminary findings of the study indicate notable differences in clinical features between children infected with SARS-CoV-2 non-omicron variants and those with omicron variants. In the omicron variant group, a higher proportion of patients exhibited symptoms such as fever, sore throat, nausea and/or vomiting, seizures, and disorders of consciousness.

Of particular concern is the substantial increase in the number of children experiencing seizures and unconsciousness in the omicron variant group compared to the non-omicron variant group.


The increased prevalence of seizures and unconsciousness in children infected with SARS-CoV-2 omicron variants raises critical questions about the pathophysiology and clinical course of these infections. Notably, the wide age distribution of affected children, with a mean age of 4.0 ± 3.0 years, distinguishes this cohort from other febrile seizure populations. The distribution, however, aligns with that observed in febrile seizures associated with influenza, highlighting potential parallels in the neurological impact of respiratory viruses on pediatric populations.

Implications for Clinical Practice

The findings of this study underscore the importance of heightened awareness among clinicians regarding the distinctive clinical features associated with SARS-CoV-2 omicron variants in pediatric patients. The increased risk of seizures and unconsciousness in this population necessitates a nuanced approach to clinical management. Clinicians managing cases of COVID-19 and influenza should be vigilant, considering the potential neurological complications associated with the omicron variant in children.


In the pursuit of unraveling the clinical features associated with SARS-CoV-2 omicron variants in children, this study has shed light on a concerning trend—namely, a significant increase in the occurrence of seizures and unconsciousness among pediatric patients infected with the omicron variant compared to non-omicron variants. This chapter delves into the implications of these findings, contextualizes the results within the broader landscape of the SARS-CoV-2 pandemic, and acknowledges the study’s limitations.

Comparative Analysis of SARS-CoV-2 Variants

The primary focus of our study was to discern the clinical features of SARS-CoV-2 omicron variants in children, particularly in contrast to other variants. The findings indicate a noteworthy association between the omicron variant and increased clinical symptoms, with seizures emerging as a prominent concern. Strikingly, the number of children experiencing seizures and unconsciousness was markedly higher during the omicron period than in the preceding non-omicron period. This points to a distinctive impact of the omicron variant on the pediatric population, aligning with emerging evidence suggesting a heightened susceptibility of children to omicron variants (14, 15).

Duration and Severity of the Pandemic Periods

An intriguing aspect of our observations lies in the duration and severity of the pandemic during the non-omicron and omicron periods. Despite the omicron period spanning a shorter timeframe (10 months) compared to the non-omicron period (24 months), there was a surge in the number of pediatric COVID-19 cases during the omicron period. This trend corroborates with previous studies reporting increased admissions during the SARS-CoV-2 omicron period, indicating a more substantial impact on the younger population. The lower mean age observed in the SARS-CoV-2 omicron group reinforces the notion that this variant has a pronounced effect on younger children.

Age Distribution of Seizures and Unconsciousness

A significant finding deserving attention is the age distribution of children experiencing seizures and unconsciousness during the SARS-CoV-2 omicron period. Unlike the typical age range for febrile seizures (FS) between 6 months and 6 years, our study revealed a broader age spectrum, encompassing both younger and older patients. This deviation is reminiscent of the age distribution observed in influenza-related febrile seizures, signaling potential parallels in the neurological impact of respiratory viruses on pediatric populations. Clinicians should be cognizant of this broader age distribution in their clinical practice, especially when managing cases of COVID-19 and influenza.

Comparison with Previous Studies and Case Reports

While some studies and case reports have previously hinted at the occurrence of seizures in children with COVID-19 infected with omicron variants, our study contributes by providing a statistical analysis that establishes a significant association between SARS-CoV-2 omicron variants and seizures/unconsciousness in the pediatric population. Notably, our findings echo reports of neurological manifestations in adults infected with SARS-CoV-2 omicron variants, reinforcing the need for heightened vigilance in assessing the neurological impact of these variants across age groups (20).

Study Limitations

Acknowledging the robustness of our study, several limitations warrant consideration. First and foremost, the study did not confirm the variants with laboratory diagnostic tools. However, the defined period as the SARS-CoV-2 pandemic is reported to be predominantly omicron variants, mitigating this concern to some extent. Additionally, due to strict indications for neuroimaging, there may be cases of encephalopathy categorized as status epilepticus.

However, their clinical symptoms did not necessitate further investigation after the isolation period, and they exhibited favorable prognoses. Second, changes in patients’ diagnostic thresholds over the course of the pandemic may have introduced selection bias. The evolving nature of diagnostic criteria, particularly in the early phases, could influence the study sample. Nonetheless, the impact of the study on clinical practice remains significant, as parents are more likely to seek medical attention for children experiencing seizures or unconsciousness. Third, information about vaccination status was unavailable. However, given the later introduction of vaccinations to Japanese children during the omicron period, the larger number of seizures in omicron variant-infected children suggests a concerning trend that warrants further investigation.


As the COVID-19 pandemic continues to evolve, the impact of emerging variants, particularly the SARS-CoV-2 omicron variant, on pediatric populations warrants focused attention. This study provides a comprehensive analysis of the clinical features associated with omicron variant infections in children, revealing a distinctive pattern characterized by an increased prevalence of seizures and unconsciousness.

The broader age distribution observed in this cohort, reminiscent of influenza-related febrile seizures, prompts further exploration into the neurological implications of respiratory viruses in pediatric patients. These findings have immediate implications for clinical practice, urging clinicians to remain vigilant and adapt their management strategies to address the unique challenges posed by the omicron variant in the pediatric population.

reference link : https://www.frontiersin.org/articles/10.3389/fped.2023.1273464/full


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