Randomisation and masking
SARS-CoV-2 infection
SARS-COV-2 INFECTION
Healthy adults aged 18–65 years who were eligible for study participation were randomly assigned (1:1) via a computer-generated system with full allocation concealment, to receive two intramuscular injections of either AZD1222 or saline placebo (0·9% sodium chloride; placebo group), given 28 days apart.There was a higher than anticipated percentage of HIV-uninfected participants (322 [19%] 1683) without a documented history of COVID-19 but who tested positive for anti-nucleocapsid (anti-N) IgG at time of randomisation (hereafter referred to as the seropositive group). Consequently, we did a post-hoc analysis of durability of antibody responses comparing AZD1222 recipients with and without SARS-CoV-2 infection before receipt of the first dose. Sampling timepoints for measuring antibody responses included the day of the first study injection (day 0), at the time of the second dose of study injection (day 28), 14 days after the second dose (day 42) and 6 months post study entry (day 180).The immunogenicity (anti-RBD and anti-S IgG and NAb against Asp614Gly wild-type [D614G] and beta variant only) of AZD1222 in people living with HIV through to day 42, including stratified by prevaccination SARS-CoV-2 infection status, and immunogenicity through to day 42 in a smaller subset of HIV-uninfected individuals who were SARS-CoV-2 naive (26 placebo and 27 AZD1222 recipients) enrolled in phase 1b has been previously published.Trial profileNumber of participants enrolled in the phase 1b study is shown in parenthesis. *Neutralisation assays were done on all phase 1b participants and an additional random sample of phase 2 vaccinated baseline anti-N IgG seropositive participants. In total, 41 vaccinated participants (17 from phase 1b) and nine placebo participants (all phase 1b) had neutralisation assays done. †The antibody kinetics of the placebo group is not reported further in this article. ‡There were 25 vaccinated participants who were anti-N IgG seropositive at baseline who had neutralisation results (only one from phase 1b). All 25 participants with baseline anti-N IgG seropositive results were included in the analysis of the neutralisation data. §There were 16 phase 1b vaccinated participants who were anti-N IgG seronegative at baseline who had neutralisation results; of these, two had PCR