Research

We conduct large-scale real-world studies to understand the effectiveness, safety, and long-term consequences of SARS-CoV-2 infection and vaccination in children and adolescents. Our work leverages multi-site electronic health record data to study infection risk, severe outcomes, long COVID, reinfection, and disparities across populations. Methodologically, these studies integrate causal inference, mediation analysis, and bias calibration to address confounding and data limitations in observational pediatric research.

Selected papers:

• Wu, Q., Zhang, B., Tong, J., Bailey, L. C., Bunnell, H. T., Chen, J., … & Chen, Y. (2025). Real-world effectiveness and causal mediation study of BNT162b2 on long COVID risks in children and adolescents. EClinicalMedicine, 79.
• Zhang, B., Wu, Q., Jhaveri, R., Zhou, T., Becich, M. J., Bisyuk, Y., … & Chen, Y. (2025). Long COVID associated with SARS-CoV-2 reinfection among children and adolescents in the omicron era (RECOVER-EHR): a retrospective cohort study. The Lancet infectious diseases.
• Zhang, D., Zhang, B., Wang, H., Lu, Y., Wolock, C. J., Hu, W., … & Chen, Y. (2025). Negative control-calibrated difference-in-difference analyses: addressing unmeasured confounding in RWD with application to racial/ethnic differences. npj Digital Medicine, 8(1), 452.
• Wu, Q., Tong, J., Zhang, B., Zhang, D., Chen, J., Lei, Y., … & Chen, Y. (2024). Real-world effectiveness of BNT162b2 against infection and severe diseases in children and adolescents. Annals of internal medicine, 177(2), 165-176.