Immunogenicity and safety of boosting with a recombinant two-component SARS-CoV-2 vaccine: two randomized, parallel-controlled, phase 2 studies

ABSTRACT

Background

Recombinant protein vaccines are vital for broad protection against SARS-CoV-2 variants. This study assessed ReCOV as a booster in two Phase 2 trials.

Research design and methods

Study-1 involved subjects were randomized (1:1:1) to receive 20 μg ReCOV, 40 μg ReCOV, or an inactivated vaccine (COVILO®) in the United Arab Emirates. Study-2 participating individuals were randomized (1:1:1) to receive 20 μg ReCOV (pilot batch, ReCOV HA), 20 μg ReCOV (commercial batch, ReCOV TC), or 30 μg BNT162b2 (COMIRNATY®) in the Philippines. The primary immunogenicity objectives was to compare the geometric mean titer (GMT) and seroconversion rate (SCR) of neutralizing antibodies induced by one ReCOV booster dose with those of inactivated vaccine and BNT162b2, respectively, at 14 days post-booster.

Results

Heterologous ReCOV booster doses were safe and induced comparable immune responses to inactivated vaccines and BNT162b2 against Omicron variants and the prototype. They showed significant advantages in cross-neutralization against multiple SARS-CoV-2 variants, surpassing inactivated vaccines and BNT162b2, with good immune persistence.

Conclusions

Heterologous ReCOV boosting was safe and effective, showing promise in combating COVID-19. The study highlights ReCOV’s potential for enhanced protection, supported by strong cross-neutralization and immune persistence.

Clinical Trial Registration

Study-1, www.clinicaltrials.gov, identifier is NCT05323435; Study-2, www.clinicaltrials.gov, identifier is NCT05084989.

KEYWORDS:

• Safety
• immunogenicity
• SARS-CoV-2
• heterologous booster
• omicron variants

Declaration of interests

Jia-Ping Yu, Wen-Rong Yao, Zijing Yue, Ying Ma, Chen Mo, Qing-Shuang Wang, Ren-Du Wen, Zheng Yao, Jian-Hui Zhang, Kun-Xue Hong, Yong Liu are employees of Jiangsu Recbio Technology Co., Ltd. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

Suad Hannawi and Abundio Balgos are the principal investigators of Study-1 and Study-2, respectively; Alaa Abuquta, Linda Safeldin, Aala Hassan, and Ahmad Alamadi are sub-investigators of Study-1, Louie Tirador, Aniuli May Jaen, and Ralph Elvi Villalobos are sub-investigators of Study-2. Zijing Yue, Ying Ma, and Chen Mo are medical leads for both studies, and Chen Mo drafted of the manuscript. Qing-Shuang Wang and Ren-Du Wen are the project leads for two studies. Zheng Yao is the statistician taking charge of data statistical analysis for both studies. Jian-Hui Zhang, Jing-Xin Li, and Kun-Xue Hong contributed to critical review and revising of the manuscript. Jian-Hui Zhang, Yong Liu, and Jing-Xin Li contributed to study supervision. Jia-Ping Yu and Wen-Rong Yao contributed to the design of the investigational vaccine. All authors reviewed and approved the final manuscript.

Acknowledgments

For Study-1, we are grateful for all investigators at AI Kuwait Hospital, Dubai UAE who contributed to the site work of the trial. For Study-2, we are grateful for all investigators at The Health Centrum, Roxas City, St. Paul’s Hospital, Iloilo City, The Medical City Iloilo, University of the Philippines, Philippine General Hospital who contributed to the site work of the trial. For both studies, we are grateful for all investigators at the central laboratory G42 laboratory LLC, the United Arab Emirates, and investigators at central laboratory Gobond Testing Technology (Beijing) Co., Ltd., China, who performed laboratory tests of the trials, respectively. We thank all the subjects in two clinical studies for their dedication to the trials.

Data sharing statement

Data Sharing Statement will be available with the full text of this article upon publication.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/14760584.2024.2334423

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This paper was funded by Jiangsu Recbio Technology Co., Ltd. The study was also supported by National Key R&D Program of China (2023YFC2307600) National Natural Science Foundation of China [82341031, 82173584 and 82222062], Major Research Plan of the National Natural Science Foundation of China [92269205], Jiangsu Provincial Science Fund for Distinguished Young Scholars [BK20220064], Jiangsu Provincial Key Project of Science and Technology Plan [BE2021738 and BE2023601], National Key R&D Program of China (2020YFC10841400), National Science and Technology Major Project [2016ZX10004001 and 2018ZX09201005], the Training Program of the Major Research Plan of the National Natural Science Foundation of China [92269118]. The funders of the study were involved in protocol design, data interpretation, statistical analysis, and writing of the report, while were not involved in data collection. All the authors had full access to all the data in the study and had final responsibility for the decision to submit for publication.