Portal de Periódicos da CAPES

Safety and efficacy of the ChAdOx1 nCoV-19 (AZD1222) Covid-19 vaccine against the B.1.351 variant in South Africa

2021; Cold Spring Harbor Laboratory; Linguagem: Inglês

10.1101/2021.02.10.21251247

Shabir A. Madhi, Vicky L. Baillie, Clare Cutland, Merryn Voysey, Anthonet Koen, Lee Fairlie, Sherman D. Padayachee, Keertan Dheda, Shaun Barnabas, Qasim Bhorat, Carmen Briner, Gaurav Kwatra, Khatija Ahmed, Parvinder K. Aley, Sutika Bhikha, Jinal N. Bhiman, As’ad E. Bhorat, Jeanine du Plessis, Aliasgar Esmail, Marisa Groenewald, Elizea Horne, Shi-Hsia Hwa, Aylin Jose, Teresa Lambe, Matt Laubscher, Mookho Malahleha, Masebole Masenya, Mduduzi Masilela, Shakeel McKenzie, Kgaogelo Molapo, Andrew Moultrie, Suzette Oelofse, Faeezah Patel, Sureshnee Pillay, Sarah Rhead, Hylton Rodel, Lindie Rossouw, Carol Taoushanis, Houriiyah Tegally, Asha Thombrayil, Samuel van Eck, Constantinos Kurt Wibmer, Nicholas M. Durham, Elizabeth J. Kelly, Tonya Villafana, Sarah C. Gilbert, Andrew J. Pollard, Túlio de Oliveira, Penny L. Moore, Alex Sigal, Alane Izu,

Vaccine Coverage and Hesitancy

Abstract Background Assessing 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. Methods We 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 5×10 10 viral particles or placebo (0.9%NaCl) 21-35 days apart. Post 2 nd -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. Results 2026 HIV-uninfected adults were enrolled between June 24 th and Nov 9 th , 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. Conclusions A 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 ).