Humoral immune responses following inactivated COVID-19 vaccine with different booster intervals: a randomized interventional immunogenicity study.

IF 4.6 2区医学 Q1 INFECTIOUS DISEASES

International Journal of Infectious Diseases Pub Date : 2026-10-19 DOI:10.1016/j.ijid.2026.109196

Xinyu Liu, Qianhui Hua, Rongrong Dai, Lanxin Ma, Ruijing Bao, Huijun Lei, Pengfei Yu, Yuting Liao, Juan Yang, Huakun Lv, Jianmin Jiang, Hangjie Zhang

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引用次数: 0

Abstract

Objectives: To evaluate the immunogenicity of booster doses at varying intervals after a two-dose primary series of inactivated COVID-19 vaccine.

Methods: This randomized, open-label interventional study in Zhejiang, China, allocated 431 participants via stratified block randomization to a control group (primary series only) or booster groups at 1, 4, 6, or 11 months after the primary series. Laboratory staff and statisticians were blinded. Immunogenicity endpoints included anti-RBD IgG, live-virus microneutralization, and pseudovirus neutralization against wild-type, Delta, and Omicron BA.1.

Results: At 1 month post-booster, live wild-type neutralizing antibody GMT (Geometric mean titer) increased with longer intervals, from 42.96 (1-Month group) to 149.93 (11-Month group). Anti-RBD and anti-S1+N IgG concentrations were significantly higher in the 4-, 6-, and 11-Month group. Pseudovirus neutralization inhibition percentages decreased progressively across variants: wild-type (72.81%-86.70%), Delta (24.32%-35.82%), Omicron BA.1 (0.26%-2.97%). GMT declined substantially by 6 months post-booster (12.08 and 17.95 in the 1- and 4-Month group), and age was significantly negatively associated with humoral responses only in the 6-Month group.

Conclusions: All booster regimens elicited greater binding and neutralizing responses than the two-dose primary series, with peak responses at 1 month post-booster increasing progressively as the interval lengthened (up to 11 months). However, neutralizing activity against Omicron BA.1 was negligible across regimens, and antibody levels declined substantially by 6 months post-booster.

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不同强化间隔灭活疫苗后的体液免疫应答：一项随机介入免疫原性研究

目的：评价两剂初级系列COVID-19灭活疫苗后不同时间间隔加强剂量的免疫原性。方法：这项在中国浙江进行的随机、开放标签的干预性研究，通过分层块随机化将431名参与者分配到对照组（仅为主要系列）或在主要系列后1、4、6或11个月的加强组。实验人员和统计人员采用盲法。免疫原性终点包括抗rbd IgG、活病毒微中和和针对野生型、Delta型和Omicron BA.1的假病毒中和。结果：增强后1个月，野生型活中和抗体GMT（几何平均滴度）随时间间隔增加，从42.96（1个月组）增加到149.93（11个月组）。4个月、6个月和11个月组抗rbd和抗s1 +N IgG浓度显著升高。假病毒中和抑制百分比在不同变异间逐渐下降：野生型（72.81%-86.70%）、Delta型（24.32%-35.82%）、Omicron BA.1型（0.26%-2.97%）。GMT在增强后6个月显著下降（1个月和4个月组分别为12.08和17.95），年龄仅在6个月组与体液反应显著负相关。结论：所有强化方案都比两剂初始系列引发了更大的结合和中和反应，随着间隔时间的延长（最多11个月），强化后1个月的峰值反应逐渐增加。然而，对Omicron BA.1的中和活性在各个方案中都可以忽略不计，抗体水平在增强后6个月大幅下降。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

International Journal of Infectious Diseases 医学-传染病学

CiteScore

18.90

自引率

2.40%

发文量

1020

审稿时长

30 days

期刊介绍： International Journal of Infectious Diseases (IJID) Publisher: International Society for Infectious Diseases Publication Frequency: Monthly Type: Peer-reviewed, Open Access Scope: Publishes original clinical and laboratory-based research. Reports clinical trials, reviews, and some case reports. Focuses on epidemiology, clinical diagnosis, treatment, and control of infectious diseases. Emphasizes diseases common in under-resourced countries.