Safety and efficacy of the ChAdOx1 nCoV-19 (AZD1222) Covid-19 vaccine against the B.1.351 variant in South Africa
Author:
Madhi Shabir A.ORCID, Baillie VickyORCID, Cutland Clare L.ORCID, Voysey Merryn, Koen Anthonet L., Fairlie LeeORCID, Padayachee Sherman D., Dheda KeertanORCID, Barnabas Shaun L.ORCID, Bhorat Qasim EbrahimORCID, Briner CarmenORCID, Kwatra Gaurav, Ahmed KhatijaORCID, Aley Parvinder, Bhikha Sutika, Bhiman Jinal N., Bhorat As’ad Ebrahim, Plessis Jeanine du, Esmail AliasgarORCID, Groenewald Marisa, Horne ElizeaORCID, Hwa Shi-Hsia, Jose Aylin, Lambe Teresa, Laubscher Matt, Malahleha Mookho, Masenya Masebole, Masilela Mduduzi, McKenzie Shakeel, Molapo Kgaogelo, Moultrie Andrew, Oelofse SuzetteORCID, Patel FaeezahORCID, Pillay Sureshnee, Rhead Sarah, Rodel Hylton, Rossouw Lindie, Taoushanis Carol, Tegally Houriiyah, Thombrayil Asha, Eck Samuel van, Wibmer Constantinos Kurt, Durham Nicholas M., Kelly Elizabeth J, Villafana Tonya L, Gilbert Sarah, Pollard Andrew J, de Oliveira TulioORCID, Moore Penny L.ORCID, Sigal Alex, Izu Alane, ,
Abstract
AbstractBackgroundAssessing safety and efficacy of Covid-19 vaccines in different populations is essential, as is investigation of efficacy against emerging SARS-CoV-2 variants of concern including the B.1.351 (501Y.V2) variant first identified in South Africa.MethodsWe conducted a randomized multicentre, double blinded controlled trial on safety and efficacy of ChAdOx1-nCoV19 in HIV-uninfected people in South Africa. Participants age 18 to <65 years randomized (1:1) to two doses of vaccine containing 5×1010viral particles or placebo (0.9%NaCl) 21-35 days apart. Post 2nd-dose serum samples (n=25) were tested by pseudotyped (PSVNA) and live virus (LVNA) neutralization assays against the D614G and B.1.351 variants. Primary endpoints were safety and vaccine efficacy (VE) >14 days following second dose against laboratory confirmed symptomatic Covid-19.Results2026 HIV-uninfected adults were enrolled between June 24thand Nov 9th, 2020; 1010 and 1011 received at least one dose of placebo or vaccine, respectively. Median age was 31 years. The B.1.351 variant showed increased resistance to vaccinee sera using the PSVNA and LVNA. In the primary endpoint analysis, 23/717 (3.2%) placebo and 19/750 (2.5%) vaccine recipients developed mild-moderate Covid-19; VE 21.9% (95%Confidence Interval: −49.9; 59.8). Of the primary endpoint cases, 39/42 (92.9%) were the B.1.351 variant; against which VE was 10.4% (95%CI: −76.8; 54.8) analyzed as a secondary objective. The incidence of serious adverse events was balanced between the vaccine and placebo groups.ConclusionsA two-dose regimen of ChAdOx1-nCoV19 did not show protection against mild-moderate Covid-19 due to B.1.351 variant, however, VE against severe Covid-19 is undetermined.(Funded by The Bill & Melinda Gates Foundation and South African Medical Research Council; ClinicalTrails.gov number,NCT04444674).
Publisher
Cold Spring Harbor Laboratory
Cited by
110 articles.
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