Outcomes
COVID-19-related deaths
SECONDARY
The primary endpoint was the seroconversion rate, specifically the percentage of individuals with a four-fold or higher increase in antibody titres to the RBD of the SARS-CoV-2 S protein, 28 days after vaccination. Secondary endpoints included the assessment of four outcomes: 1) examining the seroconversion rates in response to RBD, S protein and neutralising SARS-CoV-2 antibodies on Day 14, Day 28 (except for RBD) and at Month 6; 2) geometric mean titres (GMTs) of serum antibodies against the RBD, S protein and NAbs on Day 14, Day 28 and Month 6 post-vaccination; 3) GMTs of neutralising antibodies against the Ad5 vector on Day 28 and Month 6 post-vaccination; and 4) the cellular immune response as indicated by the secretion of IFN-γ on Day 14, Day 28 and Month 6 post-vaccination.Exploratory endpoints were the frequency of laboratory-confirmed COVID-19 cases, severe COVID-19 cases, hospitalisations due to COVID-19 and COVID-19-related deaths (Day 14 to Month 6 post-vaccination). The safety endpoints were reactogenicity (Day 0 to day 7), the frequency and nature of AEs (Day 0 to the end of the study [Month 6 Visit]), and the results of physical and laboratory examinations (i.e., haematological tests, urinalysis, serum IgE concentration).Of note, two definitions were used to define seroconversion, one quantitative and one qualitative. The primary and secondary endpoints used the quantitative definition: the proportion of participants with at least a four-fold increase in antibody titres against SARS-CoV-2 S protein and/or its RBD, specifically. The qualitative analysis was defined as an antibody titre above the lower limit of quantification (LLOQ) post-vaccination (if the baseline titre was below the LLOQ), or a four-fold increase over baseline post-vaccination (if the baseline titre was above the LLOQ).