Background: Despite children and young people (CYP) having a low risk for severe COVID-19 outcomes, there is still a degree of uncertainty related to their risk in the context of immunodeficiency or immunosuppression, primarily due to significant reporting bias in most studies, as CYP characteristically experience milder or asymptomatic COVID-19 infection and the severe outcomes tend to be overestimated.
Methods: A comprehensive systematic review to identify globally relevant studies in immunosuppressed CYP and CYP in general population (defined as younger than 25 years of age) up to 31st October 2021 (to exclude vaccinated populations), was performed. Studies were included if they reported the two primary outcomes of our study, admission to intensive therapy unit (ITU) and mortality, while data on other outcomes, such as hospitalisation and need for mechanical ventilation were also collected. A meta-analysis estimated the pooled proportion for each severe COVID-19 outcome, using the inverse variance method. Random effects models were used to account for interstudy heterogeneity.
Findings: The systematic review identified 30 eligible studies for each of the two populations investigated: immunosuppressed CYP (n=793) and CYP in general population (n=102,022). Our meta-analysis found higher estimated prevalence for hospitalization (46% vs. 16%), ITU admission (12% vs. 2%), mechanical ventilation (8% vs. 1%) and increased mortality due to severe COVID-19 infection (6.5% vs. 0.2%) in immunocompromised CYP compared to CYP in general population. This shows an overall trend for more severe outcomes of COVID-19 infection in immunocompromised CYP, similar to adult studies.
Interpretation: This is the only up to date meta-analysis in immunocompromised CYP with high global relevance, which excluded reports from hospitalised cohorts alone and included 35% studies from low- and medium-income countries. Future research is required to characterise individual subgroups of immunocompromised patients, as well as impact of vaccination on severe COVID-19 outcomes.
Audience take away:
- This presentation will demonstrate to clinicians and policy makers that, similarly to in adults, immunocompromise increases the risk of severe COVID-19 infection in children and young people, which may support strategies for patient education, COVID-19 vaccination and treatment in this population
- This presentation will be beneficial to researchers with an interest in respiratory viruses as it will describe the first meta-analysis investigating the impact of immunosuppression in COVID-19 infection in cohorts of non-hospitalized children, which may direct future research in investigating other respiratory viruses or investigating the risk of severe COVID-19 infection in sub-groups of immunosuppressed children
- This presentation will be relevant to the entire audience as the study population of over 100,000 patients was diverse and multinational, with over 1/3 from low-and-middle-income countries