Efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine against SARS-CoV-2 lineages circulating in Brazil
Authors: Clemens Sue Ann Costa , Folegatti Pedro M. , Emary Katherine R. W. , Weckx Lily Yin , Ratcliff Jeremy , Bibi Sagida , De Almeida Mendes Ana Verena , Milan Eveline Pipolo , Pittella Ana , Schwarzbold Alexandre V. , Sprinz Eduardo , Aley Parvinder K. , Bonsall David , Fraser Christophe , Fuskova Michelle , Gilbert Sarah C. , Jenkin Daniel , Kelly Sarah , Kerridge Simon , Lambe Teresa , Marchevsky Natalie G. , Mujadidi Yama F. , Plested Emma , Ramasamy Maheshi N. , Simmonds Peter , Golubchik Tanya , Voysey Merryn , Pollard Andrew J. ,   the AMPHEUS Project, Buck David , Green Angie , MacIntyre-Cockett George , Piazza Paolo , Todd John A. , Trebes Amy , Thomson Laura ,   Oxford COVID Vaccine Trial Team, Tinoco Lygia Accioly , Ferreira Karla Cristina Marques Afonso , Almeida Cenusa , Angus Brian , Arns Beatriz , Arruda Laiana , De Ávila Kfouri Renato , da Silva Lucas Henrique Azevedo , Moreira Matheus José Barbosa , Paiva Brenda Vasconcelos Barbosa , Bates Louise , Bellei Nancy , Boettger Bruno , Lora Leandro Bonecker , de Araújo Nina Amanda Borges , de Oliveira Chrystiane do Nascimento Brito , Brown-O’Sullivan Charlie , Luz Daniel Calich , Mourão Joao Renato Cardoso , Carvalho Caroline Scherer , Cicconi Paola , Cruz Ana Gibertoni , Cunha Debora , Da Costa Daniel Marinho , Da Silva Gonzalez Isabela Garrido , de Arruda Trindade Priscila , de Freitas Souza Bruno Solano , De Jesus Junior Sergio Carlos Assis , de Moraes Pinto Maria Isabel , De Mores Karolyne Porto , de Nobrega Maristela Miyamoto , Sampaio Milla Dias , dos Santos Janaína Keyla Dionísio , Douglas Alexander D. , da Guarda Suzete Nascimento Farias , Farooq Mujtaba Ghulam , Feng Shuo , dos Santos Marcel Catão Ferreira , Franco Marília Miranda , de Oliveira Marianne Garcia , Spina Fernanda Garcia , dos Santos Tannyth Gomes , Goyanna Alvaro Henrique , Haddad Rosana Esteves , Hill Adrian V. S. , Hou Mimi M. , Junqueira Bruna , Kelling Bruna Somavilla , Khozoee Baktash , Kunst Renan Gustavo , Kwok Jonathan , Madhavan Meera , de Carvalho José Antônio Mainardi , Mazur Olga , Minassian Angela M. , Ramos Leonardo Motta , Myasaki Celia Hatsuko , Noal Helena Carolina , de Lima Natália Nóbrega , Noristani Rabiullah , Perez Ana Luiza , Phillips Daniel J. , Pinheiro Priscila , Pinheiro Jéssica Morgana Gediel , Camara Marie Marcelle Prestes , Queiroz Isabella , Souza Alessandra Ramos , Castro Thais Regina Y. , Robinson Hannah , Jorge Marianna Rocha , Rochetti Talita , Saba Mariana Bernadi S. , Salvador Natalia Zerbinatti , Santos Fernanda Caldeira Veloso , Guerra Mayara Fraga Santos , Seddiqi Samiullah , Senger Roberta , Shaw Robert , Soares Airanuedida Silva , Song Rinn , Sorio Guilherme G. , Stein Ricardo , Stuart Arabella V. S. , Tassinari Tais Tasqueto , Turner Cheryl , Vieceli Tarsila , Vieira Taiane A. , Cavalcanti João Gabriel Villar , Watson Marion E. E. , Yao Andy , Zimmer Rafael 
Published: October 2021

Several COVID-19 vaccines have shown good efficacy in clinical trials, but there remains uncertainty about the efficacy of vaccines against different variants. Here, we investigate the efficacy of ChAdOx1 nCoV-19 (AZD1222) against symptomatic COVID-19 in a post-hoc exploratory analysis of a Phase 3 randomised trial in Brazil (trial registration ISRCTN89951424). Nose and throat swabs were tested by PCR in symptomatic participants. Sequencing and genotyping of swabs were performed to determine the lineages of SARS-CoV-2 circulating during the study. Protection against any symptomatic COVID-19 caused by the Zeta (P.2) variant was assessed in 153 cases with vaccine efficacy (VE) of 69% (95% CI 55, 78). 49 cases of B.1.1.28 occurred and VE was 73% (46, 86). The Gamma (P.1) variant arose later in the trial and fewer cases (N = 18) were available for analysis. VE was 64% (−2, 87). ChAdOx1 nCoV-19 provided 95% protection (95% CI 61%, 99%) against hospitalisation due to COVID-19. In summary, we report that ChAdOx1 nCoV-19 protects against emerging variants in Brazil despite the presence of the spike protein mutation E484K.