Abstract Background Assessment of the safety and efficacy of vaccines against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in different populations is essential, as is investigation of the efficacy of the vaccines against emerging SARS-CoV-2 variants of concern, including the B.1.351 (501Y.V2) variant first identified in South Africa. Methods We conducted a multicenter, double-blind, randomized, controlled trial to assess the safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) in people not infected with the human immunodeficiency virus (HIV) in South Africa. Participants 18 to less than 65 years of age were assigned in a 1:1 ratio to receive two doses of vaccine containing 5×10 10 viral particles or placebo (0.9% sodium chloride solution) 21 to 35 days apart. Serum samples obtained from 25 participants after the second dose were tested by pseudovirus and live-virus neutralization assays against the original D614G virus and the B.1.351 variant. The primary end points were safety and efficacy of the vaccine against laboratory-confirmed symptomatic coronavirus 2019 illness (Covid-19) more than 14 days after the second dose. Results Between June 24 and November 9, 2020, we enrolled 2026 HIV-negative adults (median age, 30 years); 1010 and 1011 participants received at least one dose of placebo or vaccine, respectively. Both the pseudovirus and the live-virus neutralization assays showed greater resistance to the B.1.351 variant in serum samples obtained from vaccine recipients than in samples from placebo recipients. In the primary end-point analysis, mild-to-moderate Covid-19 developed in 23 of 717 placebo recipients (3.2%) and in 19 of 750 vaccine recipients (2.5%), for an efficacy of 21.9% (95% confidence interval [CI], −49.9 to 59.8). Among the 42 participants with Covid-19, 39 cases (92.9%) were caused by the B.1.351 variant; vaccine efficacy against this variant, analyzed as a secondary end point, was 10.4% (95% CI, −76.8 to 54.8). The incidence of serious adverse events was balanced between the vaccine and placebo groups. Conclusions A two-dose regimen of the ChAdOx1 nCoV-19 vaccine did not show protection against mild-to-moderate Covid-19 due to the B.1.351 variant. (Funded by the Bill and Melinda Gates Foundation and others; ClinicalTrials.gov number, NCT04444674 ; Pan African Clinical Trials Registry number, PACTR202006922165132 ).
【초록키워드】 SARS-CoV-2, HIV, Efficacy, Vaccine, coronavirus, B.1.351, variant, SARS-CoV-2 variant, virus, Sodium chloride, Population, AZD1222, South Africa, Neutralization assay, pseudovirus, symptomatic, 501Y.V2, clinical, African, D614G, age, Placebo, incidence, multicenter, Coronavirus 2019, registry, assessment, Human immunodeficiency virus, ChAdOx1 nCoV-19 vaccine, Analysis, dose, Mild-to-moderate, double-blind, Serious Adverse Event, acute respiratory syndrome, 95% CI, 95% confidence interval, B.1.351 variant, HIV-negative, placebo recipients, second dose, median age, foundation, participant, end point, primary end point, randomized, controlled trial, primary end-point, recipient, laboratory-confirmed, serum sample, viral particle, two-dose regimen, Result, greater, enrolled, tested, analyzed, caused, conducted, less, assigned, groups, the vaccine, receive, 1:1, Melinda Gate, Pan, placebo recipient, show protection against, 【제목키워드】 B.1.351, ChAdOx1 nCoV-19,