Inactivated vaccine effectiveness against symptomatic COVID-19 in Fujian, China during the Omicron BA.2 outbreak

Wenjing Ye; Kangguo Li; Zeyu Zhao; Shenggen Wu; Huimin Qu; Yichao Guo; Buasiyamu Abudunaibi; Wu Chen; Shaojian Cai; Cailin Chen; Jiawei Lin; Zhonghang Xie; Meirong Zhan; Jianming Ou; Yanqin Deng; Tianmu Chen; Kuicheng Zheng

doi:10.3389/fpubh.2023.1269194

Inactivated vaccine effectiveness against symptomatic COVID-19 in Fujian, China during the Omicron BA.2 outbreak

Front Public Health. 2023 Dec 14:11:1269194. doi: 10.3389/fpubh.2023.1269194. eCollection 2023.

Authors

Wenjing Ye^#¹, Kangguo Li^#², Zeyu Zhao^#², Shenggen Wu^#¹, Huimin Qu², Yichao Guo², Buasiyamu Abudunaibi², Wu Chen¹, Shaojian Cai¹, Cailin Chen¹, Jiawei Lin¹, Zhonghang Xie¹, Meirong Zhan¹, Jianming Ou¹, Yanqin Deng¹, Tianmu Chen², Kuicheng Zheng¹

Affiliations

¹ Institute of Emergency Response and Epidemic Management, Fujian Provincial Center for Disease Control and Prevention, Fuzhou, China.
² State Key Laboratory of Vaccines for Infectious Diseases, Xiang an Biomedicine Laboratory, State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Innovation Platform for Industry-Education Integration in Vaccine Research, School of Public Health, Xiamen University, Xiamen, China.

^# Contributed equally.

Abstract

Objective: More than 90% of the Chinese population have completed 2 doses of inactivated COVID-19 vaccines in Mainland China. However, after China government abandoned strict control measures, many breakthrough infections appeared, and vaccine effectiveness against Omicron BA.2 infection was uncertain. This study aims to investigate the real-world effectiveness of widely used inactivated vaccines during the wave of Omicron variants.

Methods: Test-negative case-control study was conducted in this study to analyze the vaccine effectiveness against symptomatic disease caused by the Omicron variant (BA.2) in Fujian, China. Conditional logistic regression was selected to estimate the vaccine effectiveness.

Results: The study found the vaccine effectiveness against symptomatic COVID-19 is 32.46% (95% CI, 8.08% to 50.37%) at 2 to 8 weeks, and 27.05% (95% CI, 1.23% to 46.12%) at 12 to 24 weeks after receiving booster doses of the inactivated vaccine. Notably, the 3-17 years group had higher vaccine effectiveness after 2 doses than the 18-64 years and over 65 years groups who received booster doses.

Conclusion: Inactivated vaccines alone may not offer sufficient protection for all age groups before the summer of 2022. To enhance protection, other types of vaccines or bivalent vaccines should be considered.

Keywords: COVID-19; Omicron BA.2; SARS-CoV-2; inactivated vaccine; vaccine effectiveness (VE).

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

COVID-19 Vaccines
COVID-19* / epidemiology
COVID-19* / prevention & control
Case-Control Studies
China / epidemiology
Disease Outbreaks / prevention & control
Humans
SARS-CoV-2
Vaccine Efficacy
Vaccines, Inactivated

Substances

Vaccines, Inactivated
COVID-19 Vaccines

Supplementary concepts

SARS-CoV-2 variants

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by the National Key Research and Development Program of China [2021YFC2301604], the Self-supporting Program of Guangzhou Laboratory [SRPG22-007], the Natural Science Foundation of Fujian, China [2021J01353, 2020J01094], Special Projects of the Central Government Guiding Local Science and Technology Development [2021L3018], the Fujian Science and Technology Development Funds [2020Y0005], and the National Science and Technology Major Project of China [2018ZX1074402-007].