Dynamics of Crossed Acquired Immunity Against SARS‐CoV‐2 Variants: From Vaccine to Hybrid Immunity in China
Year: 2025
Type: article
Study design: Observational Study
Abstract: The immune response to evolving Omicron variants in China, especially after booster doses and breakthrough infections post-Zero-COVID-19 policy, is poorly understood. In a 14-month cohort of 206 adults, baseline assessments were conducted the day before the third COVID-19 vaccine dose (Visit 1), with follow-ups at 1 (Visit 2), 3 (Visit 3), 6 (Visit 4), 9 (Visit 5), and 14 (Visit 6) months after the dose. The lifting of Zero-COVID-19 policy coincided with a surge in Omicron breakthrough infections among our participants, occurring 12 months after the third vaccine dose. We assessed neutralizing antibodies (NAbs) against prototype/variant strains and T cell responses to BA.5 Spike and conserved peptide pools (CPPs) in PBMCs. NAbs and T-cell responses significantly increased after policy's cessation, surpassing levels seen 1 month post-third dose. Over 90% of participants showed notable NAb increases between Visit 5 and 6 without additional boosters, suggesting probable SARS-CoV-2 infections. Cross-reactive NAbs decreased for BA.5 (1.5-fold), XBB.1.5 (15.4-fold), and JN.1 (44.8-fold) compared to the prototype strain. T-cell responses to BA.5 Spike and CPPs remained stable. From vaccine to hybrid immunity, sustained cellular immunity protects against severe outcomes despite reduced NAb cross-reactivity. Updated variant-targeted vaccines remain crucial, especially for those with weaker immune responses.
Source: Journal of Medical Virology
DOI: 10.1002/jmv.70487
Authors: Hao Wang, Zhihao Zhang, Mengze Gan, Zhangbo Cui, Bihao Wu, Shuo Feng, Jun Xu, Jinge Cao, Yuying Wen, Zhen Wang, Jia Li, Dongsheng Di, Siyuan Peng, Jinfeng Lei, Guoliang Yang, Yingying Zhao, Xuemei Song, Xiaoyu Kang, Meige Liu, Yaxin Wang, Tingting Yuan, Tingting Zhou, Shui Liu, Qian Liu, Jing Yi, Xinlian Li, Hao Cai, Qinlin Chen, Pinpin Long, Yu Yuan, Shanshan Cheng, Chaolong Wang, Rui Gong, Qi Wang, Xionglin Fan, Tangchun Wu, Li Liu
Language: English
Subfield: Infectious Diseases
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W4412109950