Document is current

Article History

Received: 2 June 2025

Accepted: 3 December 2025

First Online: 26 January 2026

Declarations

:

: FMM is an investigator in pediatric studies of coronavirus disease 2019 vaccines for Pfizer and projects supported by a National Institutes of Health (NIH) contract for a Vaccine Treatment and Evaluation Unit and the Centers for Disease Control and Prevention (CDC) New Vaccine Surveillance Network and serves as a member of the DSMB for clinical trials conducted by Pfizer and Dynavax.

: This study was determined not to be human subjects research because of the use of pre-existing, de-identified data and was therefore exempt from full Institutional Review Board review.

: De-identified secondary data were used in this study, and consent to participate was not obtained.

: Not applicable.

: During the conduct of the study, the first author (MMC) and AKR had full access to the study data and took responsibility for the integrity of the data and the accuracy of the data analysis. However, the authors do not have ongoing access to the data analyzed in this study, nor do they have permission to share the study data with other researchers.

: Code for the simulated implications on vaccine safety and effectiveness is available online: . Code for other components of the study that has been edited to comply with Optum Labs policy is available upon request.

: AKR conceptualized the study and secured funding for the research. MMC analyzed the data, interpreted the results, and wrote the article. AKR, SLR, SGS, FMM, and OAA provided critical feedback on study design and article content. All authors reviewed and approved the final version of the article.