Differential effects of SARS-CoV-2 variants on children and adolescents

The ongoing coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is having a major impact on the global healthcare sector and economies. Several cases of severe SARS-CoV-2 infection in pediatric patients have been reported, although the virus primarily affects adults.

study: Differences in SARS-CoV-2 Clinical Manifestations and Disease Severity in Children and Adolescents by Infectious VariantImage credit: Morrowind / Shutterstock

Background

A wide range of clinical presentations, including asymptomatic, mild upper respiratory tract obstruction, pneumonia, and more severe symptoms Multisystem inflammatory syndrome in children (MIS-C), reported in children infected with SARS-CoV-2. Moreover, MIS-C was observed to occur mainly 2–6 weeks after her acute SARS-CoV-2 infection.

Since the beginning of the pandemic, the evolution of SARS-CoV-2 has occurred through genomic mutation, resulting in the emergence of many variants. These variants have been classified as variants of interest (VOI) and variants of concern (VOC) based on their pathogenicity, ability to evade an immune response, and contagiousness compared to ancestral strains.

In the United States, the SARS-CoV-2 alpha variant first displaced the ancestral strain and finally the delta variant. Later, around September 2021, the Delta strain was replaced by his Omicron variant, becoming the predominant circulating SARS-CoV-2 strain.

Alpha, delta, and omicron variants showed significantly higher infection rates and disproportionately affected vulnerable groups such as unvaccinated individuals and children. These variants significantly increased pediatric hospitalizations from 5 to 10 times hers, depending on the variant and age of the child. Data are lacking on how specific SARS-CoV-2 variants affect the severity of clinical disease in adolescents and children with COVID-19.

Recent emerging infectious disease A journal study evaluated whether specific SARS-CoV-2 variants are associated with different clinical manifestations in children and adolescents.

About research

Nasopharyngeal (NP) samples from children and adolescents who tested positive between 1 January 2021 and 15 January 2022 were nucleic acid Amplification test (NAAT).

All SARS-CoV-2 positive samples were stored at -20°C. However, they were analyzed within 1 week of storage based on clinical laboratory capacity, cycle threshold (Ct) values, and sample volume. In this study, Ct values ​​were used as a proxy for: viral load Quantification. Ct values ​​are inversely proportional to quantitative viral load.

Samples were analyzed to detect the presence of mutations that characterize alpha, beta, gamma, omicron, and other variants. Additionally, the authors developed his T487K assay that detects the Delta variant.

Demographic characteristics, comorbidities, infectious variant types, and SARS-CoV-2 Ct values ​​of selected inpatients and outpatients were obtained. Participants were grouped based on underlying medical conditions, including obesity/underweight, hereditary, gastrointestinal, renal, endocrine, neurological immunodeficiency disorders, and hematological disorders.

Survey results

During the study period, of 169,908 samples tested for SARS-CoV-2 infection in children and adolescents, 9.02% tested positive by NAAT assay. Fluctuations in monthly COVID-19 cases were observed throughout the study period.

Trends in circulating SARS-CoV-2 variants identified at Nationwide Children’s Hospital, Columbus, OH, USA, across patient ages from January 2021 to January 2022. Other categories include beta (n = 12), iota. (n = 9), zeta (n = 7), eta (n = 2), epsilon (n = 3), mu (n = 2) variants, and variants under investigation (n = 2). The black dotted line represents the positive rate by month.

Variant screening revealed the presence of 12 SARS-CoV-2 variants, including non-variant strains (11.34%), alpha (11.81%), delta (62.77%) and omicron (10.49%). In addition, other SARS-CoV-2 strains such as beta, zeta, gamma, mu, epsilon and eta were also detected. The findings also revealed that delta infections were most common in inpatients and outpatients. Similarly, alpha and omicron variant infections were found primarily in outpatients and inpatients.

The median age of inpatients was 6.6 years and the median age of outpatients was 9.4 years. Interestingly, in both settings, SARS-CoV-2 infection was found to be more common in the adolescent group (ages 12–21) than in younger children. Nevertheless, infants were her second most common group with COVID-19. Vaccination coverage for COVID-19 was low and did not differ between inpatients and outpatients.

Obesity/overweight condition was the most common underlying comorbidity in the study cohort. SARS-CoV-2/virus co-infection was reported in 19.82% of the study cohort. The most common viruses co-infected with COVID-19 were rhinovirus/enterovirus (RV/EV), followed by respiratory syncytial virus (RSV), human metapneumovirus, endemic coronavirus, parainfluenza virus, followed by adenovirus and influenza virus. Importantly, co-infection was seen in children infected with the Delta and Omicron variants. Co-infection also facilitated hospitalization.

Children infected with the Delta variant showed lower Ct values.In contrast to the results documented in existing studies, Admissions to the pediatric intensive care unit (PICU) were similar between children infected with Omicron and those infected with other subspecies.

Limitations of research

A major limitation of this study is that all samples tested positive for SARS-CoV-2 by NAAT were not subjected to variant screening. The percentage of sample screening for variant identification was based on sample quantity and the availability of skilled personnel in the cloning laboratory. Therefore, in months with high numbers of SARS-CoV-2 cases, variant testing was performed on a small number of samples. Another limitation was the retrospective nature of data collection, which influenced our findings in the outpatient cohort.