Single-dose administration and the influence of the timing of the booster dose on immunogenicity and efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine: a pooled analysis of four randomised trials
Authors: Merryn Voysey, Sue Ann Costa Clemens, Shabir A Madhi, Lily Y Weckx, Pedro M Folegatti, Parvinder K Aley, Brian Angus, Vicky L Baillie, Shaun L Barnabas, Qasim E Bhorat, Sagida Bibi, Carmen Briner, Paola Cicconi, Elizabeth A Clutterbuck, Andrea M Collins, Clare L Cutland, Thomas C Darton, Keertan Dheda, Christina Dold, Christopher J A Duncan, Katherine R W Emary, Katie J Ewer, Amy Flaxman, Lee Fairlie, Saul N Faust, Shuo Feng, Daniela M Ferreira, Adam Finn, Eva Galiza, Anna L Goodman, Catherine M Green, Christopher A Green, Melanie Greenland, Catherine Hill, Helen C Hill, Ian Hirsch, Alane Izu, Daniel Jenkin, Carina C D Joe, Simon Kerridge, Anthonet Koen, Gaurav Kwatra, Rajeka Lazarus, Vincenzo Libri, Patrick J Lillie, Natalie G Marchevsky, Richard P Marshall, Ana V A Mendes, Eveline P Milan, Angela M Minassian, Alastair McGregor, Yama F Mujadidi, Anusha Nana, Sherman D Padayachee, Daniel J Phillips, Ana Pittella, Emma Plested, Katrina M Pollock, Maheshi N Ramasamy, Adam J Ritchie, Hannah Robinson, Alexandre V Schwarzbold, Andrew Smith, Rinn Song, Matthew D Snape, Eduardo Sprinz, Rebecca K Sutherland, Emma C Thomson, M Estée Török, Mark Toshner, David P J Turner, Johan Vekemans, Tonya L Villafana, Thomas White, Christopher J Williams, Alexander D Douglas, Adrian V S Hill, Teresa Lambe, Sarah C Gilbert, Andrew J Pollard, Marites Aban, Kushala W.M. Abeyskera, Jeremy Aboagye, Matthew Adam, Kirsty Adams, James P. Adamson, Gbadebo Adewatan, Syed Adlou, Khatija Ahmed, Yasmeen Akhalwaya, Saajida Akhalwaya, Andrew Alcock, Aabidah Ali, Elizabeth R. Allen, Lauren Allen, Felipe B. Alvernaz, Fabio Santos Amorim, Claudia Sala Andrade, Foteini Andritsou, Rachel Anslow, Edward H. Arbe-Barnes, Mark P. Ariaans, Beatriz Arns, Laiana Arruda, Luiza Assad, Paula De Almeida Azi, Lorena De Almeida Azi, Gavin Babbage, Catherine Bailey, Kenneth F. Baker, Megan Baker, Natalie Baker, Philip Baker, Ioana Baleanu, Danieli Bandeira, Anna Bara, Marcella A.S. Barbosa, Debbie Barker, Gavin D. Barlow, Eleanor Barnes, Andrew S. Barr, Jordan R. Barrett, Jessica Barrett, Kelly Barrett, Louise Bates, Alexander Batten, Kirsten Beadon, Emily Beales, Rebecca Beckley, Sandra Belij-Rammerstorfer, Jonathan Bell, Duncan Bellamy, Sue Belton, Adam Berg, Laura Bermejo, Eleanor Berrie, Lisa Berry, Daniella Berzenyi, Amy Beveridge, Kevin R. Bewley, Inderjeet Bharaj, Sutika Bhikha, Asad E. Bhorat, Zaheda E. Bhorat, Else Margreet Bijker, Sarah Birch, Gurpreet Birch, Kathryn Birchall, Adam Bird, Olivia Bird, Karen Bisnauthsing, Mustapha Bittaye, Luke Blackwell, Rachel Blacow, Heather Bletchly, Caitlin L. Blundell, Susannah R. Blundell, Pritesh Bodalia, Emma Bolam, Elena Boland, Daan Bormans, Nicola Borthwick, Francesca Bowring, Amy Boyd, Penny Bradley, Tanja Brenner, Alice Bridges-Webb, Phillip Brown, Claire Brown, Charlie Brown-O'Sullivan, Scott Bruce, Emily Brunt, William Budd, Yusuf A. Bulbulia, Melanie Bull, Jamie Burbage, Aileen Burn, Karen R. Buttigieg, Nicholas Byard, Ingrid Cabrera Puig, Anna Calvert, Susana Camara, Michelangelo Cao, Federica Cappuccini, Rita Cardona, João R. Cardoso, Melanie Carr, Miles W. Carroll, Andrew Carson-Stevens, Yasmin de M. Carvalho, Helen R. Casey, Paul Cashen, Thais R.Y. Castro, Lucia Carratala Castro, Katrina Cathie, Ana Cavey, José Cerbino-Neto, Luiz Fernando F. Cezar, Jim Chadwick, Chanice Chanice, David Chapman, Sue Charlton, Katerina S. Cheliotis, Irina Chelysheva, Oliver Chester, Emily Chiplin, Sunder Chita, Jee-Sun Cho, Liliana Cifuentes, Elizabeth Clark, Matthew Clark, Rachel Colin-Jones, Sarah L.K. Collins, Hayley Colton, Christopher P. Conlon, Sean Connarty, Naomi Coombes, Cushla Cooper, Rachel Cooper, Lynne Cornelissen, Tumena Corrah, Catherine A. Cosgrove, Fernanda Barroso Costa, Tony Cox, Wendy E.M. Crocker, Sarah Crosbie, Dan Cullen, Debora R.M.F. Cunha, Christina J. Cunningham, Fiona C. Cuthbertson, Daniel Marinho da Costa, Suzete N. Farias Da Guarda, Larissa P. da Silva, Antonio Carlos da Silva Moraes, Brad E. Damratoski, Zsofia Danos, Maria T.D.C. Dantas, Mehreen S. Datoo, Chandrabali Datta, Malika Davids, Sarah L. Davies, Kelly Davies, Hannah Davies, Sophie Davies, Judith Davies, Elizabeth J. Davis, John Davis, José A.M. de Carvalho, Jeanne De Jager, Sergio de Jesus Jnr, Lis Moreno De Oliveira Kalid, David Dearlove, Tesfaye Demissie, Amisha Desai, Stefania Di Marco, Claudio Di Maso, Tanya Dinesh, Claire Docksey, Tao Dong, Francesca R. Donnellan, Tannyth Gomes Dos Santos, Thainá G. Dos Santos, Erika Pachecho Dos Santos, Naomi Douglas, Charlotte Downing, Jonathan Drake, Rachael Drake-Brockman, Ruth Drury, Joan Du Plessis, Susanna J. Dunachie, Andrew Duncan, Nicholas J.W. Easom, Mandy Edwards, Nick J. Edwards, Frances Edwards, Omar M. El Muhanna, Sean C. Elias, Branwen Ellison-Handley, Michael J. Elmore, Marcus Rex English, Alisgair Esmail, Yakub Moosa Essack, Mutjaba Farooq, Sofiya Fedosyuk, Sally Felle, Susie Ferguson, Carla Ferreira Da Silva, Samantha Field, Richard Fisher, James Fletcher, Hazel Fofie, Henry Fok, Karen J. Ford, Ross Fothergill, Jamie Fowler, Pedro H.A. Fraiman, Emma Francis, Marilia M. Franco, John Frater, Marilúcia S.M. Freire, Samantha H. Fry, Sabrina Fudge, Renato Furlan Filho, Julie Furze, Michelle Fuskova, Pablo Galian-Rubio, Harriet Garlant, Madita Gavrila, Karyna A. Gibbons, Ciaran Gilbride, Hardeep Gill, Kerry Godwin, Karishma Gokani, Maria Luisa Freire Gonçalves, Isabela G.S. Gonzalez, Jack Goodall, Jayne Goodwin, Amina Goondiwala, Katherine Gordon-Quayle, Giacomo Gorini, Alvaro Goyanna, Janet Grab, Lara Gracie, Justin Green, Nicola Greenwood, Johann Greffrath, Marisa M. Groenewald, Anishka Gunawardene, Gaurav Gupta, Mark Hackett, Bassam Hallis, Mainga Hamaluba, Elizabeth Hamilton, Joseph Hamlyn, Daniel Hammersley, Aidan T. Hanrath, Brama Hanumunthadu, Stephanie A. Harris, Clair Harris, Thomas D. Harrison, Daisy Harrison, Tara A. Harris-Wright, Thomas C. Hart, Birgit Hartnell, John Haughney, Sophia Hawkins, Laís Y.M. Hayano, Ian Head, Paul T. Heath, John Aaron Henry, Macarena Hermosin Herrera, David B. Hettle, Cristhiane Higa, Jennifer Hill, Gina Hodges, Susanne Hodgson, Elizea Horne, Mimi M. Hou, Catherine F. Houlihan, Elizabeth Howe, Nicola Howell, Jonathan Humphreys, Holly E. Humphries, Katrina Hurley, Claire Huson, Catherine Hyams, Angela Hyder-Wright, Sabina Ikram, Alka Ishwarbhai, Poppy Iveson, Vidyashankara Iyer, Frederic Jackson, Susan Jackson, Shameem Jaumdally, Helen Jeffers, Natasha Jesudason, Carina Jones, Christopher Jones, Kathryn Jones, Elizabeth Jones, Marianna Rocha Jorge, Amar Joshi, Eduardo A.M.S. Júnior, Reshma Kailath, Faeeza Kana, Arnab Kar, Konstantinos Karampatsas, Mwila Kasanyinga, Linda Kay, Jade Keen, Johanna Kellett Wright, Elizabeth J. Kelly, Debbie Kelly, Dearbhla M. Kelly, Sarah Kelly, David Kerr, Liaquat Khan, Baktash Khozoee, Ankush Khurana, Sarah Kidd, Annabel Killen, Jasmin Kinch, Patrick Kinch, Lloyd D.W. King, Thomas B. King, Lucy Kingham, Paul Klenerman, Diana M. Kluczna, Francesca Knapper, Julian C. Knight, Daniel Knott, Stanislava Koleva, Pedro M. Lages, Matilda Lang, Gail Lang, Colin W. Larkworthy, Jessica P.J. Larwood, Rebecca Law, Alison M. Lawrie, Erica M. Lazarus, Amanda Leach, Emily A. Lees, Alice Lelliott, Nana-Marie Lemm, Alvaro Edson Ramos Lessa, Stephanie Leung, Yuanyuan Li, Amelia M. Lias, Konstantinos Liatsikos, Aline Linder, Samuel Lipworth, Shuchang Liu, Xinxue Liu, Adam Lloyd, Stephanie Lloyd, Lisa Loew, Raquel Lopez Ramon, Leandro Bonecker Lora, Kleber Giovanni Luz, Jonathan C. MacDonald, Gordon MacGregor, Meera Madhavan, David O. Mainwaring, Edson Makambwa, Rebecca Makinson, Mookho Malahleha, Ross Malamatsho, Garry Mallett, Nicola Manning, Kushal Mansatta, Takalani Maoko, Spyridoula Marinou, Emma Marlow, Gabriela N. Marques, Paula Marriott, Richard P. Marshall, Julia L. Marshall, Masebole Masenya, Mduduzi Masilela, Shauna K. Masters, Moncy Mathew, Hosea Matlebjane, Kedidimetse Matshidiso, Olga Mazur, Andrea Mazzella, Hugh McCaughan, Joanne McEwan, Joanna McGlashan, Lorna McInroy, Nicky McRobert, Steve McSwiggan, Clare Megson, Savviz Mehdipour, Wilma Meijs, Renata N.Õ. Mendonça, Alexander J. Mentzer, Ana Carolina F. Mesquita, Patricia Miralhes, Neginsadat Mirtorabi, Celia Mitton, Sibusiso Mnyakeni, Fiona Moghaddas, Kgaogelo Molapo, Mapule Moloi, Maria Moore, Marni Moran, Ella Morey, Róisín Morgans, Susan J. Morris, Sheila Morris, Hazel Morrison, Franca Morselli, Gertraud Morshead, Richard Morter, Lynelle Mottay, Andrew Moultrie, Nathifa Moyo, Mushiya Mpelembue, Sibekezelo Msomi, Yvonne Mugodi, Ekta Mukhopadhyay, Jilly Muller, Alasdair Munro, Sarah Murphy, Philomena Mweu, Christopher Myerscough, Gurudutt Naik, Kush Naker, Eleni Nastouli, Bongani Ndlovu, Elissavet Nikolaou, Cecilia Njenga, Helena C. Noal, Andrés Noé, Gabrielle Novaes, Fay L. Nugent, Géssika Lanzillo A. Nunes, Katie O'Brien, Daniel O'Connor, Suzette Oelofse, Blanche Oguti, Victoria Olchawski, Neil J. Oldfield, Marianne G. Oliveira, Catarina Oliveira, Isabelle Silva Queiroz Oliveira, Aylin Oommen-Jose, Angela Oosthuizen, Paula O'Reilly, Peter J. O'Reilly, Piper Osborne, David R.J. Owen, Lydia Owen, Daniel Owens, Nelly Owino, Mihaela Pacurar, Brenda V.B. Paiva, Edna M.F. Palhares, Susan Palmer, Helena M. R.T. Parracho, Karen Parsons, Dipak Patel, Bhumika Patel, Faeezah Patel, Maia Patrick-Smith, Ruth O. Payne, Yanchun Peng, Elizabeth J. Penn, Anna Pennington, Marco Polo Peralta Alvarez, Bruno Pereira Pereira Stuchi, Ana Luiza Perez, Tanaraj Perinpanathan, James Perring, Rubeshan Perumal, Sahir Yusuf Petkar, Tricia Philip, Jennifer Phillips, Mary Kgomotso Phohu, Lorinda Pickup, Sonja Pieterse, Jessica Morgana Pinheiro, Jo Piper, Dimitra Pipini, Mary Plank, Sinéad Plant, Samuel Pollard, Jennifer Pooley, Anil Pooran, Ian Poulton, Claire Powers, Fernando B. Presa, David A. Price, Vivien Price, Marcelo R. Primeira, Pamela C. Proud, Samuel Provstgaard-Morys, Sophie Pueschel, David Pulido, Sheena Quaid, Ria Rabara, Kajal Radia, Durga Rajapaska, Thurkka Rajeswaran, Leonardo Ramos, Alberto San Francisco Ramos, Fernando Ramos Lopez, Tommy Rampling, Jade Rand, Helen Ratcliffe, Tom Rawlinson, David Rea, Byron Rees, Mila Resuello-Dauti, Emilia Reyes Pabon, Sarah Rhead, Tawassal Riaz, Marivic Ricamara, Alexander Richards, Alex Richter, Neil Ritchie, Adam J. Ritchie, Alexander J. Robbins, Hannah Roberts, Ryan E. Robinson, Sophie Roche, Christine Rollier, Louisa Rose, Amy L. Ross Russell, Lindie Rossouw, Simon Royal, Indra Rudiansyah, Kim Ryalls, Charlotte Sabine, Stephen Saich, Jessica C. Sale, Ahmed M. Salman, Natalia Salvador, Stephannie Salvador, Milla Dias Sampaio, Annette D. Samson, Amada Sanchez-Gonzalez, Helen Sanders, Katherine Sanders, Erika Santos, Mayara F.S. Santos Guerra, Iman Satti, Jack E. Saunders, Caroline Saunders, Aakifah Bibi Arif Sayed, Ina Schim van der Loeff, Annina B. Schmid, Ella Schofield, Gavin R. Screaton, Samiullah Seddiqi, Rameswara R. Segireddy, Roberta Senger, Sonia Serrano, Imam Shaik, Hannah R. Sharpe, Katherine Sharrocks, Robert Shaw, Adam Shea, Emma Sheehan, Amy Shepherd, Farah Shiham, Sarah E. Silk, Laura Silva-Reyes, Lidiana B. T.D. Silveira, Mariana B.V. Silveira, Nisha Singh, Jaisi Sinha, Donal T. Skelly, Daniel C. Smith, Nick Smith, Holly E. Smith, David J. Smith, Catherine C. Smith, Airanuédida S. Soares, Carla Solórzano, Guilherme L. Sorio, Kim Sorley, Tiffany Sosa-Rodriguez, Cinthia M.C.D.L. Souza, Bruno S.D.F. Souza, Alessandra R. Souza, Thamyres Souza Lopez, Luciana Sowole, Alexandra J. Spencer, Louise Spoors, Lizzie Stafford, Imogen Stamford, Ricardo Stein, Lisa Stockdale, Lisa V. Stockwell, Louise H. Strickland, Arabella Stuart, Ann Sturdy, Natalina Sutton, Anna Szigeti, Abdessamad Tahiri-Alaoui, Rachel Tanner, Carol Taoushanis, Alexander W. Tarr, Richard Tarrant, Keja Taylor, Ursula Taylor, Iona Jennifer Taylor, Justin Taylor, Rebecca te Water Naude, Kate Templeton, Yrene Themistocleous, Andreas Themistocleous, Merin Thomas, Kelly Thomas, Tonia M. Thomas, Asha Thombrayil, Julia Thompson, Fawziyah Thompson, Ameeka Thompson, Amber Thompson, Kevin Thompson, Viv Thornton-Jones, Larissa H.S. Thotusi, Patrick J. Tighe, Lygia Accioly Tinoco, Gerlynn Ferreras Tiongson, Bonolo Tladinyane, Michele Tomasicchio, Adriana Tomic, Susan Tonks, James Towner, Nguyen Tran, Julia A. Tree, Gerry Trillana, Charlotte Trinham, Rose Trivett, Adam Truby, Betty Lebogang Tsheko, Philippa Tubb, Aadil Turabi, Richard Turner, Cheryl Turner, Nicola Turner, Bhavya Tyagi, Marta Ulaszewska, Benjamin R. Underwood, Samual van Eck, Rachel Varughese, Dennis Verbart, Marije K. Verheul, Iason Vichos, Taiane A. Vieira, Gemma Walker, Laura Walker, Matthew E. Wand, Theresa Wardell, George M. Warimwe, Sarah C. Warren, Bridget Watkins, Marion E.E. Watson, Ekaterina Watson, Stewart Webb, Angela Webster, Jessica Welch, Zoe Wellbelove, Jeanette H. Wells, Alison J. West, Beth White, Caroline White, Rachel White, Paul Williams, Rachel L. Williams, Silvia Willingham, Rebecca Winslow, Danielle Woods, Mark Woodyer, Andrew T. Worth, Danny Wright, Marzena Wroblewska, Andy Yao, Yee Ting Nicole Yim, Marina Bauer Zambrano, Rafael Leal Zimmer, Dalila Zizi, Peter Zuidewind
Journal: The Lancet (2021)

The ChAdOx1 nCoV-19 (AZD1222) vaccine has been approved for emergency use by the UK regulatory authority, Medicines and Healthcare products Regulatory Agency, with a regimen of two standard doses given with an interval of 4-12 weeks. The planned roll-out in the UK will involve vaccinating people in high-risk categories with their first dose immediately, and delivering the second dose 12 weeks later. Here, we provide both a further prespecified pooled analysis of trials of ChAdOx1 nCoV-19 and exploratory analyses of the impact on immunogenicity and efficacy of extending the interval between priming and booster doses. In addition, we show the immunogenicity and protection afforded by the first dose, before a booster dose has been offered.