Antibody Persistence in Chinese Toddlers at 1 Year and 2 Years after Two Different 4-Dose Schedules of a Novel 13-Valent Pneumococcal Conjugate Vaccine (Pcv13-Tt)
31 Pages Posted: 26 Nov 2024
Abstract
Background A novel 13-valent pneumococcal conjugate vaccine (PCV13-TT) has been widely used in China since its licensure in 2019. The prelicensure pivotal clinical study (PCV13-002) showed strong immune responses against 13 serotypes with PCV13-TT using two different 3P+1 schedules starting at either 2 (PCV13-2M) or 3 months (PCV13-3M) of age. Method To assess antibody persistence, healthy Chinese toddlers from PCV13-002 were recalled for blood collection at 1 and 2 years post booster dose. Antibody persistence was evaluated using ELISA and OPA assay methods to measure serotype-specific antibodies. Result Similar immune responses were noted for both PCV13-3M and PCV13-2M group. IgG GMCs remained high (ranging from 0.39-4.68 μg/mL) through 2 years post 4 doses of PCV13-TT, with IgG positive rates against most serotypes maintained at ≥90%. Both OPA GMTs and OPA positive rates remained high compared to levels observed at 1 month post booster. Conclusion After complete dosing schedule of PCV13-TT starting from either 2 months or 3 months, the antibody level declined through 1 year and 2 years post booster dose, while still remained at relatively high levels at the two timepoints as compared to those observed at 1 month post booster dose for the majority of serotypes.
Note:
Funding declaration: Yuxi Walvax Biotechnology Co., Ltd. and Walvax Biotechnology Co., Ltd. funded the study.
Conflict of Interests: LY, JC, HF, XY, ST, YY, JY, JS, JL, RH, LS and ZH report being employees of Walvax Biotechnology Co., Ltd. Other authors declare no conflict of interest.
Ethical Approval: This study along with its corresponding documents including study protocol, informed consent from, etc., were approved by the National Medical Products Administration (NMPA) and the Institutional Review Board (IRB) of study sites (Shanxi Provincial Center for Disease Control and Prevention and Henan Provincial Center for Disease Control and Prevention).
Investigators informed the subjects’ parents or legal guardians of all aspects pertaining to the subjects’ participation in the study. Before any study procedure was initiated, parents or legal guardians provided written informed consent for the subject to participate into the study.
Trial Registration: The current study (PCV13-003), an extension study of the pivotal phase III clinical trial (PCV13-002, NCT02736240).
The study was registered on http://www.chinadrugtrials.org.cn/ as CTR20182353.
Keywords: pneumococcal conjugate vaccines, China, pneumococcal serotypes, antibody persistence
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