Undergraduate Research Assistant Columbia University Irving Medical Center Parsippany, New Jersey, United States
Background: Protection from severe manifestations of SARS-CoV-2 infection is mediated by adaptive immune responses generated following natural infection or vaccination. Notably, children have been shown to produce a reduced breadth of antibodies following SARS-CoV-2 infection as compared to adults. Knowledge of long-term immunologic outcomes following COVID-19 vaccination during infancy and childhood is limited, particularly in children who were infected prior to vaccination. Importantly, our local community in the Washington Heights neighborhood of Manhattan is highly diverse and experienced especially high rates of infection during the first waves of the pandemic, prior to the widespread availability of vaccines. Objective: To evaluate the long-term pediatric immune response to vaccination, we enrolled subjects (n=35, median age 10; range 1-18) at the time of their first SARS-CoV-2 vaccination and followed them longitudinally for up to 26 months. Design/Methods: We quantified anti-spike and anti-nucleocapsid IgG levels in plasma across timepoints (n=58 samples) using indirect enzyme-linked immunosorbent assay. Our cohort was racially diverse with 54% of participants identifying as Black, 17% as White, and 29% as mixed race. Additionally, 50% of subjects identified as Hispanic. Results: Strikingly, 90% of subjects presented with anti-SARS-CoV-2 antibodies at baseline, indicating the prevalence of prior natural infection. Our longitudinal sampling showed that anti-spike IgG antibody levels significantly increased from baseline in all subjects and were highest in the month following administration of the first dose of the vaccine. As expected, antibody levels declined significantly in the 26 months following primary vaccination (p=0.003). Interestingly, there was a wide range in longitudinal antibody responses, with approximately 10% of subjects falling below baseline levels within 12 months of their last dose. To determine other factors associated with antibody responses, we performed multivariate analyses controlling for race, ethnicity, age, and sex and found that time was the only factor significantly associated with this decline.
Conclusion(s): This study provides new insight into the long-term, antibody-mediated response to COVID-19 vaccination in a racially diverse pediatric cohort with high rates of natural infection before vaccination. Further investigation into the factors associated with durable antibody responses can inform optimal vaccination strategies in children and promote immunologic protection in vulnerable populations.
