The Kinetics of Anti-SARS-CoV-2 Antibodies in Pediatric Patients and the Characterization of Post-COVID-19 Condition at 6 Months After Infection: Protocol for a Longitudinal Observational Study

Background: Data regarding the kinetics of anti-SARS-CoV-2 antibodies and information about post-COVID-19 condition (colloquially known as “long COVID”) in children are scarce, especially in low-income countries. Even though cases of COVID-19 in children are less prevalent than adults, post-COVID-19 condition cases in children are high and have a burden that may impact their growth and development. There are other features of antibody kinetics in connection with SARS-CoV-2 infection that are yet unknown as of this writing, especially in children following infection. Furthermore, the long-term results, risk factors, and underlying pathophysiology are still uncertain. To better understand post-COVID-19 condition in children, it is necessary to further investigate the impact of clinically significant factors such multisystem inflammatory syndrome and disease severity among hospitalized survivors through their SARS-CoV-2 antibody response. Objective: We aim to analyze anti-receptor-binding domain SARS-CoV-2 immunoglobulin G antibodies over time and characterize the signs and symptoms of post-COVID-19 condition in pediatric patients at the time of diagnosis and at 2 weeks and 1, 3, and 6 months following infection. Methods: This is a longitudinal observational study in Indonesia. Pediatric patients diagnosed with COVID-19 by positive molecular assay using nasopharyngeal swab will be tested for anti-SARS-CoV-2 antibodies using the Roche Elecsys Anti-SARS-CoV-2 S assay at the time of diagnosis and at 2 weeks and 1, 3, and 6 months following infection. Antibody titer data will be reported as means and SDs. The respondents' signs and symptoms will be observed up to 6 months after the onset of infection, including the vaccination event, reinfection, rehospitalization, and mortality. The clinical features will be reported as frequencies and percentages. Results: Participant enrollment began in February 2022. As of September 30, 2022, a total of 58 patients were enrolled. After data collection, results are expected to be analyzed in August 2023. Conclusions: This study will allow us to know the kinetics of anti-receptor-binding domain SARS-CoV-2 immunoglobulin G antibodies and data regarding post-COVID-19 condition up to 6 months following infection in the Indonesian pediatric population. Furthermore, this study has the potential to serve as a foundation for government decisions about vaccination programs and prevention measures.