Procedures
allergic, RBD
VIRUS, ADVERSE EVENT, IMMUNISATION REACTION, INFLUENZA, ACUTE RESPIRATORY INFECTION
A single dose (0.5 mL) of Ad5-nCoV or placebo was administered by intramuscular (IM) injection to the upper arm on Day 0. Participants were requested to remain at the site for 2 h after vaccination for study staff to monitor for any systemic or local reactions to vaccination. Following the administration of the vaccine or placebo, participants attended clinic visits on Day 2, Day 7, Day 14, Day 28 and after Month 6. Between Day 28 and Month 6 there were phone calls at Months 2, 3, 4 and 5.Determination of serum antibodies against the S protein and RBD of SARS-CoV-2 and the presence of neutralising antibodies against SARS-CoV-2 (NAbs) were conducted on Day 0, Day 14, Day 28 and after Month 6; neutralising antibodies against Ad5 were assessed on Day 0, Day 28 and after Month 6. Immunoglobulin G antibodies to the S protein and RBD were determined using indirect enzyme-linked immunosorbent assay kits that involved incubation of serially diluted serum samples with the recombinant antigen (either RBD [SARS-CoV-2-IgG-EIA; XEMA Co. Ltd] or S protein [SARS-CoV-2-IgG-EIA-BEST; Vector-Best]) immobilised to the surface of a 96-well plate. The assays were performed according to the manufacturer’s instructions. Horseradish-peroxidase conjugated mouse monoclonal anti-human IgG antibody was used to detect antibodies, visualised with tetramethylbenzidine substrate solution. The detection limit for antibodies against the S protein and RBD of SARS-CoV-2 was 1:100.Anti-SARS-CoV-2 neutralising antibodies were determined with a microneutralisation assay in which Vero cell (#ССL-81, American Type Culture Collection) monolayers were incubated in 96-well plates with 2-fold serial dilutions (1:10 to 1:1280) of participant serum. Recently thawed and diluted SARS-CoV-2 virus ([GISAID HCoV-19/st_petersburg-3524S/2020] was obtained from the clinical material collection at Smorodintsev Research Institute of Influenza, St. Petersburg, Russia) was added to the wells, and plates were incubated for 1 h at 37±0.5°C in a humidified incubator. Medium was removed from wells, replaced with a mixture of the most highly diluted (1:1280) serum and virus, and plates were incubated at 37±0.5°C and 5% COSequence encoding ΔFurin variant of SARS-CoV-2 S protein (amino acids 1–1213), a truncated variant that contains the ectodomain of S protein (i.e., recombinant S protein ectodomain) along with a C-terminal Gly-Gly-6xHis tag was subcloned into the pMCAG-2T vector using the GeneArt Type IIs Assembly Kit, To measure the cellular immune response from T cells (specifically CD8Evidence of local and general reactogenicity (frequency and nature of systemic and local immunisation reactions on the day of vaccination and within 7 days after vaccination) was sought on Day 0, Day 2 and Day 7. Adverse events (AEs) were monitored from the day of vaccination (Day 0) onwards, during a scheduled phone call that evening, and at all subsequent clinic visits. A physical examination, including neurologic examination, and vital signs, including body temperature, was conducted at all visits (screening, Day 0, Day 2, Day 7, Day 14, Day 28 and Month 6). Participants received telephone calls after 2, 3, 4 and 5 months, and were asked to answer questions to assess safety and determine if they presented with signs of an acute respiratory infection due to COVID-19. Haematology, clinical biochemistry, coagulation testing and urinalysis were conducted at screening, Day 2 and Day 28; electrocardiography was performed at screening and on Day 2. Immunoglobulin E (IgE) levels were assessed to determine any allergic effects of vaccine components at screening and on Day 28.