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ABSTRACT
Background: To determine the safety and immunogenicity of a novel recombinant adenovirus type 5 vector based Ebola virus disease vaccine (Ad5-EBOV) in Africans in China.
Methods: A phase 1, dose-escalation, open-label trial was conducted. 61 healthy Africans were sequentially enrolled, with 31 participants receiving one shot intramuscular injection and 30 participants receiving a double-shot regimen. Primary and secondary end points related to safety and immunogenicity were assessed within 28 d after vaccination. This study was registered with ClinicalTrials.gov (NCT02401373).
Results: Ad5-EBOV is well tolerated and no adverse reaction of grade 3 or above was observed. 53 (86.89%) participants reported at least one adverse reaction within 28 d of vaccination. The most common reaction was fever and the mild pain at injection site, and there were no significant difference between these 2 groups. Ebola glycoprotein-specific antibodies appeared in all 61 participants and antibodies titers peaked after 28 d of vaccination. The geometric mean titres (GMTs) were similar between these 2 groups (1919.01 vs 1684.70 P = 0.5562). The glycoprotein-specific T-cell responses rapidly peaked after 14 d of vaccination and then decreased, however, the percentage of subjects with responses were much higher in the high-dose group (60.00% vs 9.68%, P = 0.0014). Pre-existing Ad5 neutralizing antibodies could significantly dampen the specific humoral immune response and cellular response to the vaccine.
Conclusion: The application of Ad5-EBOV demonstrated safe in Africans in China and a specific GP antibody and T-cell response could occur 14 d after the first immunization. This acceptable safety profile provides a reliable basis to proceed with trials in Africa.
Disclosure of potential conflicts of interest
No potential conflicts of interest were disclosed
Acknowledgments
The authors appreciate the generous cooperation received from the staff of the Research Center for Clinical Pharmacy, The First Affiliated Hospital of Zhejiang University.
Funding
This work was supported by the National Major Study Plan of China under Grant (No. 2016YFC1200204); and the Public Welfare Projects of Zhejiang Province, China under Grant (No. 2015C33166).
Author contributions
Prof. LJL, WC and LHW designed the trial and the study protocol. YQQ, JFS, NPW, LHW, HNG, JZST, JL, GJL, MHL and GLW participated in the site work, including the recruitment, follow-up, and data collection. ZZ, HPY, XXW, YHL, LW, JJL, LHH, SPW and QX contributed to participate in the laboratory analyses, data interpretation. YZ contributed to the vaccine management. PL, LL, GLW, and HLO contributed to the statistical analysis. HNG drafted the manuscript. LHW, LHH, MHL and JL modified and revised the manuscript. WC and LJL supervised the whole process of study and took the responsibility for all the data gathered, revised the manuscript. Prof. LJL decided to publish the paper. All authors reviewed and approved the final version of the report.