V2 Ad5 COVID-19 Vaccine/China/The Safety, Tolerability, and Immunogenicity of a recombinant adenovirus type-5 vectored COVID-19 vaccine
Ending COVID
Vaccine Assessment for Ad5 Adenovirus Type-5 Vectored
Aimed to assess the safety, tolerability, and immunogenicity of a recombinant adenovirus type-5 (Ad5) vectored COVID-19 vaccine expressing the spike glycoprotein of a severe acute respiratory syndrome SARS-CoV-2.
Phase 1 clinical trial of an Ad5 vectored COVID-19 vaccine in Wuhan, China. Between March 16 and March 27, 2020.
This was a dose-escalation, single-center, open-label, non-randomized vaccine trial.
The trial consisted of 195 individuals for eligibility. 108 participants (51% male, 49% female; mean age 36·3 years) were recruited and received the low dose (n=36), middle dose (n=36), or high dose (n=36) of the vaccine. Healthy adults aged between 18 and 60 years were sequentially enrolled and allocated to one of three dose groups (5 × 1010, 1 × 1011, and 1·5 × 1011 viral particles) to receive an intramuscular injection of vaccine.
Safety was assessed over 28 days post-vaccination. Only one adverse event in the 7 days post-vaccination was reported and that was pain, mild to moderate. Additional safety measures include the following: the main adverse reaction within the first 7 days after the vaccination was reported in 30 participants in the low dose group (83%) , 30 participants in the middle dose group (83%) , and 27 participants in the high dose group (75%). The most common injection site adverse reaction was pain, which was reported in 58 vaccine recipients (54%) , and the most commonly reported systematic adverse reactions were fever (50 [46%]), fatigue (47 [44%]), headache (42 [39%]), and muscle pain (18 [17%]). The vast majority of adverse reactions that were reported in all dose groups were mild or moderate in severity. No serious adverse event was noted within 28 days post-vaccination.
Antibodies were present after vaccination and the specific targeted antibodies were measured with ELISA. The neutralizing antibody responses induced by vaccination were detected with SARS-CoV-2 virus neutralization and pseudo-virus neutralization tests. T-cell responses were assessed by enzyme-linked immuno-spot and flow-cytometry assays. ELISA antibodies and neutralizing antibodies increased significantly at day 14, and peaked 28 days post-vaccination. Specific T-cell response peaked at day 14 post-vaccination.
Results imply that the Ad5 vectored COVID-19 vaccine is tolerable and immunogenic at 28 days post-vaccination. Humoral responses against SARS-CoV-2 peaked at day 28 post-vaccination in healthy adults, and rapid specific T-cell responses were noted from day 14 post-vaccination
