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ABSTRACT
Introduction
The global spread of COVID-19 has prompted the development of vaccines. A recombinant adenovirus type-5 vectored COVID-19 vaccine (Ad5-nCoV) developed by Chinese scientists has been authorized for use as a prime and booster dose in China and several other countries.
Areas covered
We searched published articles as of 4 May 2023, on PubMed using keywords related to Adenovirus vector, vaccine, and SARS-CoV-2. We reported the progress and outcomes of Ad5-nCov, including vaccine efficacy, safety, immunogenicity based on pre-clinical trials, clinical trials, and real-world studies for primary and booster doses.
Expert opinion
Ad5-nCoV is a significant advancement in Chinese vaccine development technology. Evidence from clinical trials and real-world studies has demonstrated well-tolerated, highly immunogenic, and efficacy of Ad5-nCoV in preventing severe/critical COVID-19. Aerosolized Ad5-nCoV, given via a novel route, could elicit mucosal immunity and improve the vaccine efficacy, enhance the production capacity and availability, and reduce the potential negative impact of preexisting antibodies. However, additional research is necessary to evaluate the long-term safety and immunogenicity of Ad5-nCoV, its efficacy against emerging variants, its effectiveness in a real-world context of hybrid immunity, and its cost-effectiveness, particularly with respect to aerosolized Ad5-nCoV.
Article highlights
Ad5-nCoV is a remarkable achievement in Chinese vaccine innovation.
Clinical trials showed that a single intramuscular dose of Ad5-nCoV was safe, immunogenic, and effective in preventing severe/critical COVID-19.
Aerosolized Ad5-nCoV was explored as a way to induce mucosal immunity and enhance the efficacy of viral-vector COVID-19 vaccines.
The production capacity of the vaccine was significantly increased by using only one-fifth of the intramuscular Ad5-nCoV dose for the aerosolized Ad5-nCoV.
To overcome the negative impact of preexisting anti-Ad5 antibodies, a homologous prime-boost regimen with Ad5-nCoV given at least 6 months apart, or using aerosolized Ad5-nCoV as a booster dose, or a heterologous prime-boost regimen might be optimal strategies.
Further studies are needed to evaluate the long-term safety and immunogenicity of Ad5-nCoV, the efficacy against emerging variants, effectiveness in a real-world context of hybrid immunity, as well as the cost-effectiveness of Ad5-nCoV, particularly with respect to aerosolized Ad5-nCoV.
The Ad5-nCoV platform could be potentially used for developing vaccines against other challenging infectious pathogens.
Declaration of interest
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or material discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or mending, or royalties.
Reviewer disclosures
A reviewer on this manuscript has disclosed that they have previously worked with the owner of the company that licensed the Ad5 manufacturing technology to Cansino Biotech. Peer reviewers on this manuscript have no other relevant financial or other relationships to disclose.
Authors contributions
Shen-Yu Wang contributed to drafting and revising of this manuscript. Wen-Qing Liu and Yu-Qing Li contributed to assistant drafting of this manuscript. Jing-Xin Li and Feng-Cai Zhu contributed to critically review the manuscript. All the authors have accessed and verified the data, and Jing-Xin Li and Feng-Cai Zhu are responsible for the decision to submit the manuscript.