Page 20 - JCTR-11-3

Journal of Clinical and

Translational Research

REVIEW ARTICLE
A systematic review of immunogenicity and

safety of influenza subunit vaccines and split
vaccines

Lei Wang 1,2,3 , Hongbo Zhang 1,2,3 * , Dan Li 1,2,3 , Xinyue Zhang 1,2,3 , Youcai An 1,2,3 ,
and Ze Chen 1,2,3 *
1 Department of Basic Research, Ab &B Bio-Tech Co., Ltd., Taizhou, Jiangsu, China
2 Innovative Human Vaccine Technology and Engineering Research Center of Taizhou, Taizhou,
Jiangsu, China
3 Innovative Antiviral Vaccines Engineering Technology Research Center of Taizhou, Taizhou,
Jiangsu, China

Abstract

Background: Vaccination remains the most effective preventive measure against
influenza. Current flu vaccines include split-virus, subunit, and live-attenuated
vaccines. Comparing adjuvanted and non-adjuvanted subunit vaccines and split-virus
formulations is essential to evaluate their immunogenicity (through geometric mean
*Corresponding authors:
Hongbo Zhang titers [GMTs] and seroprotection rates) and safety (adverse event rates). Aim: The aim of
(zhanghongbo@abbbio.com.cn) this study was to analyze the immunogenicity and safety of adjuvanted subunit vaccines,
Ze Chen non-adjuvanted subunit vaccines, and split vaccines. Methods: A systematic search
(chenze@abbbio.com.cn)
of the PubMed, Cochrane, and EMBASE databases was conducted, supplemented by
Citation: Wang L, Zhang H, manual searches. After two reviewers independently screened the articles, extracted
Li D, Zhang X, An Y, Chen Z.
A systematic review of the data, and assessed the quality, a meta-analysis was conducted with Stata 16.0
immunogenicity and safety of software. Results: Twenty-four studies were ultimately included in the analysis.
influenza subunit vaccines and The systematic review found that adjuvanted subunit influenza vaccines (IV), non-
split vaccines. J Clin Transl Res.
2025;11(3):14-37. adjuvanted IV, and split IV all provided good protection. Based on the seroconversion
doi: 10.36922/JCTR025060006 rate and GMTs levels, adjuvanted subunit IV was overall superior to non-adjuvanted
split IV. However, adjuvanted subunit IV had lower safety compared to non-adjuvanted
Received: February 8, 2025
IV and split IV. Non-adjuvanted IV displayed similar seroprotection rates to adjuvanted
Revised: March 15, 2025 subunit IV, providing sufficient protection. Conclusion: Adjuvanted subunit IV offers
Accepted: April 3, 2025 better immunogenicity but has a higher incidence of adverse reactions. For individuals
with impaired immune systems, it is recommended to use adjuvanted subunit IV
Published online: May 6, 2025
for better protection. However, for the majority of the population, non-adjuvanted
Copyright: © 2025 Author(s). subunit IV is recommended to achieve sufficient seroprotection rates and better safety.
This is an Open-Access article
distributed under the terms of the Relevance for patients: The systematic review is helpful for guiding better vaccination
Creative Commons AttributionNon- strategies and improves public health outcomes.
Commercial 4.0 International (CC
BY-NC 4.0), which permits all
non-commercial use, distribution, Keywords: Influenza; Adjuvant; Subunit vaccines; Split vaccines; Immunogenicity; Safety
and reproduction in any medium,
provided the original work is
properly cited.
Publisher’s Note: AccScience
Publishing remains neutral with 1. Introduction
regard to jurisdictional claims in
published maps and institutional Influenza is a respiratory infection that affects all age groups and can cause critical
affiliations. complications, particularly among vulnerable individuals. Due to its high contagiousness

Volume 11 Issue 3 (2025) 14 doi: 10.36922/JCTR025060006