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Article History

Received: 19 May 2025

Accepted: 2 February 2026

First Online: 12 February 2026

Declarations

:

: This study adheres to the principles of the Declaration of Helsinki. Approval for the study was obtained from the Ethics Committee of Jiangsu Provincial Center for Disease Control and Prevention (approval number: JSJK2023-B027-02). All the survey subjects or parents of the children signed the informed consent forms. Personal information including age and gender were collected. Immunization histories were retrieved from the Jiangsu Province vaccination integrated service management information system. All methods conformed to the approved guidelines.

: Not applicable.

: The authors declare no competing interests.