Genomic assessment of quarantine measures to prevent SARS-CoV-2 importation and transmission
Authors: Aggarwal Dinesh , Page Andrew J. , Schaefer Ulf , Savva George M. , Myers Richard , Volz Erik , Ellaby Nicholas , Platt Steven , Groves Natalie , Gallagher Eileen , Tumelty Niamh M. , Le Viet Thanh , Hughes Gareth J. , Chen Cong , Turner Charlie , Logan Sophie , Harrison Abbie ,   The COVID-19 Genomics UK (COG-UK) Consortium, Koshy Cherian , Ash Amy , Wise Emma , Moore Nathan , Mori Matilde , Cortes Nick , Lynch Jessica , Kidd Stephen , Fairley Derek J. , Curran Tanya , McKenna James P. , Adams Helen , Fraser Christophe , Golubchik Tanya , Bonsall David , Hassan-Ibrahim Mohammed O. , Malone Cassandra S. , Cogger Benjamin J. , Wantoch Michelle , Reynolds Nicola , Warne Ben , Maksimovic Joshua , Spellman Karla , McCluggage Kathryn , John Michaela , Beer Robert , Afifi Safiah , Morgan Sian , Marchbank Angela , Price Anna , Kitchen Christine , Gulliver Huw , Merrick Ian , Southgate Joel , Guest Martyn , Munn Robert , Workman Trudy , Connor Thomas R. , Fuller William , Bresner Catherine , Snell Luke B. , Patel Amita , Charalampous Themoula , Nebbia Gaia , Batra Rahul , Edgeworth Jonathan , Robson Samuel C. , Beckett Angela H. , Aanensen David M. , Underwood Anthony P. , Yeats Corin A. , Abudahab Khalil , Taylor Ben E. W. , Menegazzo Mirko , Clark Gemma , Smith Wendy , Khakh Manjinder , Fleming Vicki M. , Lister Michelle M. , Howson-Wells Hannah C. , Berry Louise , Boswell Tim , Joseph Amelia , Willingham Iona , Jones Carl , Holmes Christopher , Bird Paul , Helmer Thomas , Fallon Karlie , Tang Julian , Raviprakash Veena , Campbell Sharon , Sheriff Nicola , Blakey Victoria , Williams Lesley-Anne , Loose Matthew W. , Holmes Nadine , Moore Christopher , Carlile Matthew , Wright Victoria , Sang Fei , Debebe Johnny , Coll Francesc , Signell Adrian W. , Betancor Gilberto , Wilson Harry D. , Eldirdiri Sahar , Kenyon Anita , Davis Thomas , Pybus Oliver G. , du Plessis Louis , Zarebski Alex E. , Raghwani Jayna , Kraemer Moritz U. G. , Francois Sarah , Attwood Stephen W. , Vasylyeva Tetyana I. , Zamudio Marina Escalera , Gutierrez Bernardo , Torok M. Estee , Hamilton William L. , Goodfellow Ian G. , Hall Grant , Jahun Aminu S. , Chaudhry Yasmin , Hosmillo Myra , Pinckert Malte L. , Georgana Iliana , Moses Samuel , Lowe Hannah , Bedford Luke , Moore Jonathan , Stonehouse Susanne , Fisher Chloe L. , Awan Ali R. , BoYes John , Breuer Judith , Harris Kathryn A. , Brown Julianne R. , Shah Divya , Atkinson Laura , Lee Jack C. D. , Storey Nathaniel , Flaviani Flavia , Alcolea-Medina Adela , Williams Rebecca , Vernet Gabrielle , Chapman Michael R. , Levett Lisa J. , Heaney Judith , Chatterton Wendy , Pusok Monika , Xu-McCrae Li , Smith Darren L. , Bashton Matthew , Young Gregory R. , Holmes Alison , Randell Paul A. , Cox Alison , Madona Pinglawathee , Bolt Frances , Price James , Mookerjee Siddharth , Ragonnet-Cronin Manon , Nascimento Fabricia F. , Jorgensen David , Siveroni Igor , Johnson Rob , Boyd Olivia , Geidelberg Lily , Volz Erik M. , Rowan Aileen , Taylor Graham P. , Smollett Katherine L. , Loman Nicholas J. , Quick Joshua , McMurray Claire , Stockton Joanne , Nicholls Sam , Rowe Will , Poplawski Radoslaw , McNally Alan , Nunez Rocio T. Martinez , Mason Jenifer , Robinson Trevor I. , O’Toole Elaine , Watts Joanne , Breen Cassie , Cowell Angela , Sluga Graciela , Machin Nicholas W. , Ahmad Shazaad S. Y. , George Ryan P. , Halstead Fenella , Sivaprakasam Venkat , Hogsden Wendy , Illingworth Chris J. , Jackson Chris , Thomson Emma C. , Shepherd James G. , Asamaphan Patawee , Niebel Marc O. , Li Kathy K. , Shah Rajiv N. , Jesudason Natasha G. , Tong Lily , Broos Alice , Mair Daniel , Nichols Jenna , Carmichael Stephen N. , Nomikou Kyriaki , Aranday-Cortes Elihu , Johnson Natasha , Starinskij Igor , da Silva Filipe Ana , Robertson David L. , Orton Richard J. , Hughes Joseph , Vattipally Sreenu , Singer Joshua B. , Nickbakhsh Seema , Hale Antony D. , Macfarlane-Smith Louissa R. , Harper Katherine L. , Carden Holli , Taha Yusri , Payne Brendan A. I. , Burton-Fanning Shirelle , Waugh Sheila , Collins Jennifer , Eltringham Gary , Rushton Steven , O’Brien Sarah , Bradley Amanda , Maclean Alasdair , Mollett Guy , Blacow Rachel , Templeton Kate E. , McHugh Martin P. , Dewar Rebecca , Wastenge Elizabeth , Dervisevic Samir , Stanley Rachael , Meader Emma J. , Coupland Lindsay , Smith Louise , Graham Clive , Barton Edward , Padgett Debra , Scott Garren , Swindells Emma , Greenaway Jane , Nelson Andrew , McCann Clare M. , Yew Wen C. , Andersson Monique , Peto Timothy , Justice Anita , Eyre David , Crook Derrick , Sloan Tim J. , Duckworth Nichola , Walsh Sarah , Chauhan Anoop J. , Glaysher Sharon , Bicknell Kelly , Wyllie Sarah , Elliott Scott , Lloyd Allyson , Impey Robert , Levene Nick , Monaghan Lynn , Bradley Declan T. , Wyatt Tim , Allara Elias , Pearson Clare , Osman Husam , Bosworth Andrew , Robinson Esther , Muir Peter , Vipond Ian B. , Hopes Richard , Pymont Hannah M. , Hutchings Stephanie , Curran Martin D. , Parmar Surendra , Lackenby Angie , Mbisa Tamyo , Miah Shahjahan , Bibby David , Manso Carmen , Hubb Jonathan , Dabrera Gavin , Ramsay Mary , Bradshaw Daniel , Thornton Alicia , Gallagher Eileen , Lee David , Williams David , Harrison Ian , Hartman Hassan , Manesis Nikos , Patel Vineet , Bishop Chloe , Chalker Vicki , Ledesma Juan , Twohig Katherine A. , Holden Matthew T. G. , Shaaban Sharif , Birchley Alec , Adams Alexander , Davies Alisha , Gaskin Amy , Plimmer Amy , Gatica-Wilcox Bree , McKerr Caoimhe , Moore Catherine , Williams Chris , Heyburn David , De Lacy Elen , Hilvers Ember , Downing Fatima , Shankar Giri , Jones Hannah , Asad Hibo , Coombes Jason , Watkins Joanne , Evans Johnathan M. , Fina Laia , Gifford Laura , Gilbert Lauren , Graham Lee , Perry Malorie , Morgan Mari , Bull Matthew , Cronin Michelle , Pacchiarini Nicole , Craine Noel , Jones Rachel , Howe Robin , Corden Sally , Rey Sara , Kumziene-SummerhaYes Sara , Taylor Sarah , Cottrell Simon , Jones Sophie , Edwards Sue , O’Grady Justin , Mather Alison E. , Baker David J. , Rudder Steven , Aydin Alp , Kay Gemma L. , Trotter Alexander J. , Alikhan Nabil-Fareed , de Oliveira Martins Leonardo , Le-Viet Thanh , Meadows Lizzie , Casey Anna , Ratcliffe Liz , Simpson David A. , Molnar Zoltan , Thompson Thomas , Acheson Erwan , Masoli Jane A. H. , Knight Bridget A. , Ellard Sian , Auckland Cressida , Jones Christopher R. , Mahungu Tabitha W. , Irish-Tavares Dianne , Haque Tanzina , Hart Jennifer , Witele Eric , Fenton Melisa L. , Dadrah Ashok , Symmonds Amanda , Saluja Tranprit , Bourgeois Yann , Scarlett Garry P. , Loveson Katie F. , Goudarzi Salman , Fearn Christopher , Cook Kate , Dent Hannah , Paul Hannah , Partridge David G. , Raza Mohammad , Evans Cariad , Johnson Kate , Liggett Steven , Baker Paul , Bonner Stephen , Essex Sarah , Lyons Ronan A. , Saeed Kordo , Mahanama Adhyana I. K. , Samaraweera Buddhini , Silveira Siona , Pelosi Emanuela , Wilson-Davies Eleri , Williams Rachel J. , Kristiansen Mark , Roy Sunando , Williams Charlotte A. , Cotic Marius , Bayzid Nadua , Westhorpe Adam P. , Hartley John A. , Jannoo Riaz , Lowe Helen L. , Karamani Angeliki , Ensell Leah , Prieto Jacqui A. , Jeremiah Sarah , Grammatopoulos Dimitris , Pandey Sarojini , Berry Lisa , Jones Katie , Richter Alex , Beggs Andrew , Best Angus , Percival Benita , Mirza Jeremy , Megram Oliver , Mayhew Megan , Crawford Liam , Ashcroft Fiona , Moles-Garcia Emma , Cumley Nicola , Smith Colin P. , Bucca Giselda , Hesketh Andrew R. , Blane Beth , Girgis Sophia T. , Leek Danielle , Sridhar Sushmita , Forrest Sally , Cormie Claire , Gill Harmeet K. , Dias Joana , Higginson Ellen E. , Maes Mailis , Young Jamie , Kermack Leanne M. , Gupta Ravi K. , Ludden Catherine , Peacock Sharon J. , Palmer Sophie , Churcher Carol M. , Hadjirin Nazreen F. , Carabelli Alessandro M. , Brooks Ellena , Smith Kim S. , Galai Katerina , McManus Georgina M. , Ruis Chris , Davidson Rose K. , Rambaut Andrew , Williams Thomas , Balcazar Carlos E. , Gallagher Michael D. , O’Toole Áine , Rooke Stefan , Hill Verity , Williamson Kathleen A. , Stanton Thomas D. , Michell Stephen L. , Bewshea Claire M. , Temperton Ben , Michelsen Michelle L. , Warwick-Dugdale Joanna , Manley Robin , Farbos Audrey , Harrison James W. , Sambles Christine M. , Studholme David J. , Jeffries Aaron R. , Darby Alistair C. , Hiscox Julian A. , Paterson Steve , Iturriza-Gomara Miren , Jackson Kathryn A. , Lucaci Anita O. , Vamos Edith E. , Hughes Margaret , Rainbow Lucille , Eccles Richard , Nelson Charlotte , Whitehead Mark , Turtle Lance , Haldenby Sam T. , Gregory Richard , Gemmell Matthew , Wierzbicki Claudia , Webster Hermione J. , de Silva Thushan I. , Smith Nikki , Angyal Adrienn , Lindsey Benjamin B. , Groves Danielle C. , Green Luke R. , Wang Dennis , Freeman Timothy M. , Parker Matthew D. , Keeley Alexander J. , Parsons Paul J. , Tucker Rachel M. , Brown Rebecca , Wyles Matthew , Whiteley Max , Zhang Peijun , Gallis Marta , Louka Stavroula F. , Constantinidou Chrystala , Unnikrishnan Meera , Ott Sascha , Cheng Jeffrey K. J. , Bridgewater Hannah E. , Frost Lucy R. , Taylor-Joyce Grace , Stark Richard , Baxter Laura , Alam Mohammad T. , Brown Paul E. , Aggarwal Dinesh , Cerda Alberto C. , Merrill Tammy V. , Wilson Rebekah E. , McClure Patrick C. , Chappell Joseph G. , Tsoleridis Theocharis , Ball Jonathan , Buck David , Todd John A. , Green Angie , Trebes Amy , MacIntyre-Cockett George , de Cesare Mariateresa , Alderton Alex , Amato Roberto , Ariani Cristina V. , Beale Mathew A. , Beaver Charlotte , Bellis Katherine L. , Betteridge Emma , Bonfield James , Danesh John , Dorman Matthew J. , Drury Eleanor , Farr Ben W. , Foulser Luke , Goncalves Sonia , Goodwin Scott , Gourtovaia Marina , Harrison Ewan M. , Jackson David K. , Jamrozy Dorota , Johnston Ian , Kane Leanne , Kay Sally , Keatley Jon-Paul , Kwiatkowski Dominic , Langford Cordelia F. , Lawniczak Mara , Letchford Laura , Livett Rich , Lo Stephanie , Martincorena Inigo , McGuigan Samantha , Nelson Rachel , Palmer Steve , Park Naomi R. , Patel Minal , Prestwood Liam , Puethe Christoph , Quail Michael A. , Rajatileka Shavanthi , Scott Carol , Shirley Lesley , Sillitoe John , Chapman Michael H. Spencer , Thurston Scott A. J. , Tonkin-Hill Gerry , Weldon Danni , Rajan Diana , Bronner Iraad F. , Aigrain Louise , Redshaw Nicholas M. , Lensing Stefanie V. , Davies Robert , Whitwham Andrew , Liddle Jennifier , Lewis Kevin , Tovar-Corona Jaime M. , Leonard Steven , Durham Jillian , Bassett Andrew R. , McCarthy Shane , Moll Robin J. , James Keith , Oliver Karen , Makunin Alex , Barrett Jeff , Gunson Rory N. , Peacock Sharon J. , Chand Meera , Harrison Ewan M. 
Published: February 2022

Mitigation of SARS-CoV-2 transmission from international travel is a priority. We evaluated the effectiveness of travellers being required to quarantine for 14-days on return to England in Summer 2020. We identified 4,207 travel-related SARS-CoV-2 cases and their contacts, and identified 827 associated SARS-CoV-2 genomes. Overall, quarantine was associated with a lower rate of contacts, and the impact of quarantine was greatest in the 16–20 age-group. 186 SARS-CoV-2 genomes were sufficiently unique to identify travel-related clusters. Fewer genomically-linked cases were observed for index cases who returned from countries with quarantine requirement compared to countries with no quarantine requirement. This difference was explained by fewer importation events per identified genome for these cases, as opposed to fewer onward contacts per case. Overall, our study demonstrates that a 14-day quarantine period reduces, but does not completely eliminate, the onward transmission of imported cases, mainly by dissuading travel to countries with a quarantine requirement.