Factors that increase the risk of severe COVID-19 in children

A recent Scientific Reports study identifies the risk factors associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection based on a nationwide, multicenter, and observational cohort of adolescents and children hospitalized due to severe infection.

Study: Epidemiology of 7375 children and adolescents hospitalized with COVID-19 in Germany, reported via a prospective, nationwide surveillance study in 2020–2022. Image Credit: Sellwell / Shutterstock.com

Background

SARS-CoV-2 is the virus responsible for the coronavirus disease 2019 (COVID-19), which has claimed millions of lives worldwide. Studies conducted during the early phase of the COVID-19 pandemic indicated that children were at a lower risk of developing severe SARS-CoV-2 infection than adults. However, more supporting data is needed to corroborate this observation.

Identifying the underlying risk factors that increase the risk of disease severity in some children is essential. This information would be critical to formulating risk-reduction measures and developing effective vaccination and non-pharmaceutical guidelines to protect children and adolescents from COVID-19.

About the study

The German Society for Pediatric Infectious Diseases (DGPI) launched a nationwide survey to collect data on children and adolescents admitted to hospitals due to severe SARS-CoV-2 infection. Pediatric patients between one and 17 years of age with confirmed SARS-CoV-2 infection requiring hospitalization were recruited between January 1, 2020, and November 30, 2022.

Children with pediatric inflammatory multisystem syndrome (PIMS), which is also referred to as multisystem inflammatory syndrome in children (MIS-C), were separately documented.

All important information linked to the patients, including initial symptoms, exposures, comorbidities, disease course during hospitalization, medical treatment, and outcomes, were collected. Some of the comorbidities evaluated as potential risk factors (RF) for severe SARS-CoV-2 infection include psychiatric, respiratory, hematological, cardiovascular, neurological/neuromuscular, gastrointestinal, renal, hepatic, autoimmune, syndromic diseases, cancer, primary immunodeficiency (PID), and obesity.

Based on the Robert Koch Institute (RKI) data, which monitored SARS-CoV-2 variants in Germany, six phases were identified with different dominant SARS-CoV-2 variants of concern (VOC).

Study findings

A total of 7,375 children and adolescents were hospitalized due to severe SARS-CoV-2 infection. Among these, 7,341 were hospitalized in German hospitals, and the remainder were hospitalized in Austrian hospitals.

Consistent with reports from previous studies, most children with SARS-CoV-2 infection developed mild symptoms. As a result, as compared to adults, children and adolescents had lower hospitalization and ICU admission rates.

About 50% of the cohort did not require hospital admission due to SARS-CoV-2 infection. In some cases, SARS-CoV-2 infection was the incidental finding, or some children contracted the infection during the hospital stay. 

Only 20% of patients received COVID-19-related therapy. This observation supports the fact that most children with SARS-CoV-2 infection develop mild symptoms that do not require hospitalization or extensive medical treatment.

The successive emergence of different SARS-CoV-2 VOCs shifted the pattern of hospitalization and ICU admission rates. For the pediatric population, the overall hospitalization and ICU admission rates decreased during Omicron circulation, which may be attributed to the reduced virulence of this variant as compared to the Delta variant. Furthermore, compared to other VOCs, higher vaccination coverage and infection-acquired immunity occurred during the Omicron VOC phase. 

In contrast to other age groups, infant hospitalization rates substantially increased during the Omicron period. This finding is in line with a previous United States-based study reporting increased infant hospitalization and reduced teenage hospitalization due to SARS-CoV-2 infection. Notably, many infant-age admissions were likely due to taking preventive measures rather than actual disease severity.

Several risk factors were associated with ICU admission due to severe COVID-19, including obesity, Trisomy 21 and other genetic conditions, neurological/neuromuscular diseases, and coinfections. Pediatric patients with severe immunosuppression were not associated with an increased risk of severe SARS-CoV-2 infection. Although obesity and Trisomy 21 were identified as significant risk factors in the pre-Omicron phase, these factors did not increase the risk of severe Omicron infections.

Overall, an increased risk for ICU admission was highest among 12- to 17-year-olds, followed by one- to four-year-olds.

The bivariate model revealed that patients with recurrent obstructive bronchitis, acyanotic heart disease, cyanotic, pulmonary hypertension, psychomotor retardation, arterial hypertension, heart failure, congenital kidney diseases epilepsy, and diabetes are at a greater risk of contracting severe infection. Thus, the presence of these factors must be considered while formulating treatments and preventive measures for children and adolescents to protect them from COVID-19.

Conclusions

The current study used a robust, comprehensive, nationwide pediatric and adolescent cohort recruited from multiple centers to identify risk factors for severe SARS-CoV-2 infection. Some of the factors that increase the risk of developing severe infection include obesity, Trisomy 21, being between five and 11 years of age, neurological/neuromuscular diseases, and coinfections at the time of hospitalization.