Quarantine and testing strategies in contact tracing for SARS-CoV-2: a modelling study
Summary: Background: In most countries, contacts of confirmed COVID-19 cases are asked to quarantine for 14 days after exposure to limit asymptomatic onward transmission. While theoretically effective, this policy places a substantial social and economic burden on both the individual and wider soci...
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2021-03-01
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| Series: | The Lancet Public Health |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S246826672030308X |
| _version_ | 1818871263862456320 |
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| author | Billy J Quilty, MSc Samuel Clifford, PhD Joel Hellewell, PhD Timothy W Russell, PhD Adam J Kucharski, PhD Stefan Flasche, ProfPhD W John Edmunds, ProfPhD Katherine E Atkins Anna M Foss Naomi R Waterlow Kaja Abbas Rachel Lowe Carl A B Pearson Sebastian Funk Alicia Rosello Gwenan M Knight Nikos I Bosse Simon R Procter Georgia R Gore-Langton Alicia Showering James D Munday Katharine Sherratt Thibaut Jombart Emily S Nightingale Yang Liu Christopher I Jarvis Graham Medley Oliver Brady Hamish P Gibbs David Simons Jack Williams Damien C Tully Stefan Flasche Sophie R Meakin Kevin Zandvoort Fiona Y Sun Mark Jit Petra Klepac Matthew Quaife Rosalind M Eggo Frank G Sandmann Akira Endo Kiesha Prem Sam Abbott Rosanna Barnard Yung-Wai D Chan Megan Auzenbergs Amy Gimma C Julian Villabona-Arenas Nicholas G Davies |
| author_facet | Billy J Quilty, MSc Samuel Clifford, PhD Joel Hellewell, PhD Timothy W Russell, PhD Adam J Kucharski, PhD Stefan Flasche, ProfPhD W John Edmunds, ProfPhD Katherine E Atkins Anna M Foss Naomi R Waterlow Kaja Abbas Rachel Lowe Carl A B Pearson Sebastian Funk Alicia Rosello Gwenan M Knight Nikos I Bosse Simon R Procter Georgia R Gore-Langton Alicia Showering James D Munday Katharine Sherratt Thibaut Jombart Emily S Nightingale Yang Liu Christopher I Jarvis Graham Medley Oliver Brady Hamish P Gibbs David Simons Jack Williams Damien C Tully Stefan Flasche Sophie R Meakin Kevin Zandvoort Fiona Y Sun Mark Jit Petra Klepac Matthew Quaife Rosalind M Eggo Frank G Sandmann Akira Endo Kiesha Prem Sam Abbott Rosanna Barnard Yung-Wai D Chan Megan Auzenbergs Amy Gimma C Julian Villabona-Arenas Nicholas G Davies |
| author_sort | Billy J Quilty, MSc |
| collection | DOAJ |
| description | Summary: Background: In most countries, contacts of confirmed COVID-19 cases are asked to quarantine for 14 days after exposure to limit asymptomatic onward transmission. While theoretically effective, this policy places a substantial social and economic burden on both the individual and wider society, which might result in low adherence and reduced policy effectiveness. We aimed to assess the merit of testing contacts to avert onward transmission and to replace or reduce the length of quarantine for uninfected contacts. Methods: We used an agent-based model to simulate the viral load dynamics of exposed contacts, and their potential for onward transmission in different quarantine and testing strategies. We compared the performance of quarantines of differing durations, testing with either PCR or lateral flow antigen (LFA) tests at the end of quarantine, and daily LFA testing without quarantine, against the current 14-day quarantine strategy. We also investigated the effect of contact tracing delays and adherence to both quarantine and self-isolation on the effectiveness of each strategy. Findings: Assuming moderate levels of adherence to quarantine and self-isolation, self-isolation on symptom onset alone can prevent 37% (95% uncertainty interval [UI] 12–56) of onward transmission potential from secondary cases. 14 days of post-exposure quarantine reduces transmission by 59% (95% UI 28–79). Quarantine with release after a negative PCR test 7 days after exposure might avert a similar proportion (54%, 95% UI 31–81; risk ratio [RR] 0·94, 95% UI 0·62–1·24) to that of the 14-day quarantine period, as would quarantine with a negative LFA test 7 days after exposure (50%, 95% UI 28–77; RR 0·88, 0·66–1·11) or daily testing without quarantine for 5 days after tracing (50%, 95% UI 23–81; RR 0·88, 0·60–1·43) if all tests are returned negative. A stronger effect might be possible if individuals isolate more strictly after a positive test and if contacts can be notified faster. Interpretation: Testing might allow for a substantial reduction in the length of, or replacement of, quarantine with a small excess in transmission risk. Decreasing test and trace delays and increasing adherence will further increase the effectiveness of these strategies. Further research is required to empirically evaluate the potential costs (increased transmission risk, false reassurance) and benefits (reduction in the burden of quarantine, increased adherence) of such strategies before adoption as policy. Funding: National Institute for Health Research, UK Research and Innovation, Wellcome Trust, EU Horizon 2021, and the Bill & Melinda Gates Foundation. |
| first_indexed | 2024-12-19T12:20:09Z |
| format | Article |
| id | doaj.art-cdbcb35efff9463daae5ad37800c3556 |
| institution | Directory Open Access Journal |
| issn | 2468-2667 |
| language | English |
| last_indexed | 2024-12-19T12:20:09Z |
| publishDate | 2021-03-01 |
| publisher | Elsevier |
| record_format | Article |
| series | The Lancet Public Health |
| spelling | doaj.art-cdbcb35efff9463daae5ad37800c35562022-12-21T20:21:50ZengElsevierThe Lancet Public Health2468-26672021-03-0163e175e183Quarantine and testing strategies in contact tracing for SARS-CoV-2: a modelling studyBilly J Quilty, MSc0Samuel Clifford, PhD1Joel Hellewell, PhD2Timothy W Russell, PhD3Adam J Kucharski, PhD4Stefan Flasche, ProfPhD5W John Edmunds, ProfPhD6Katherine E AtkinsAnna M FossNaomi R WaterlowKaja AbbasRachel LoweCarl A B PearsonSebastian FunkAlicia RoselloGwenan M KnightNikos I BosseSimon R ProcterGeorgia R Gore-LangtonAlicia ShoweringJames D MundayKatharine SherrattThibaut JombartEmily S NightingaleYang LiuChristopher I JarvisGraham MedleyOliver BradyHamish P GibbsDavid SimonsJack WilliamsDamien C TullyStefan FlascheSophie R MeakinKevin ZandvoortFiona Y SunMark JitPetra KlepacMatthew QuaifeRosalind M EggoFrank G SandmannAkira EndoKiesha PremSam AbbottRosanna BarnardYung-Wai D ChanMegan AuzenbergsAmy GimmaC Julian Villabona-ArenasNicholas G DaviesCentre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK; Correspondence to: Mr Billy J Quilty, Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UKCentre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK; Dr Samuel Clifford, Centre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UKCentre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UKCentre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UKCentre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UKCentre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UKCentre for the Mathematical Modelling of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UKSummary: Background: In most countries, contacts of confirmed COVID-19 cases are asked to quarantine for 14 days after exposure to limit asymptomatic onward transmission. While theoretically effective, this policy places a substantial social and economic burden on both the individual and wider society, which might result in low adherence and reduced policy effectiveness. We aimed to assess the merit of testing contacts to avert onward transmission and to replace or reduce the length of quarantine for uninfected contacts. Methods: We used an agent-based model to simulate the viral load dynamics of exposed contacts, and their potential for onward transmission in different quarantine and testing strategies. We compared the performance of quarantines of differing durations, testing with either PCR or lateral flow antigen (LFA) tests at the end of quarantine, and daily LFA testing without quarantine, against the current 14-day quarantine strategy. We also investigated the effect of contact tracing delays and adherence to both quarantine and self-isolation on the effectiveness of each strategy. Findings: Assuming moderate levels of adherence to quarantine and self-isolation, self-isolation on symptom onset alone can prevent 37% (95% uncertainty interval [UI] 12–56) of onward transmission potential from secondary cases. 14 days of post-exposure quarantine reduces transmission by 59% (95% UI 28–79). Quarantine with release after a negative PCR test 7 days after exposure might avert a similar proportion (54%, 95% UI 31–81; risk ratio [RR] 0·94, 95% UI 0·62–1·24) to that of the 14-day quarantine period, as would quarantine with a negative LFA test 7 days after exposure (50%, 95% UI 28–77; RR 0·88, 0·66–1·11) or daily testing without quarantine for 5 days after tracing (50%, 95% UI 23–81; RR 0·88, 0·60–1·43) if all tests are returned negative. A stronger effect might be possible if individuals isolate more strictly after a positive test and if contacts can be notified faster. Interpretation: Testing might allow for a substantial reduction in the length of, or replacement of, quarantine with a small excess in transmission risk. Decreasing test and trace delays and increasing adherence will further increase the effectiveness of these strategies. Further research is required to empirically evaluate the potential costs (increased transmission risk, false reassurance) and benefits (reduction in the burden of quarantine, increased adherence) of such strategies before adoption as policy. Funding: National Institute for Health Research, UK Research and Innovation, Wellcome Trust, EU Horizon 2021, and the Bill & Melinda Gates Foundation.http://www.sciencedirect.com/science/article/pii/S246826672030308X |
| spellingShingle | Billy J Quilty, MSc Samuel Clifford, PhD Joel Hellewell, PhD Timothy W Russell, PhD Adam J Kucharski, PhD Stefan Flasche, ProfPhD W John Edmunds, ProfPhD Katherine E Atkins Anna M Foss Naomi R Waterlow Kaja Abbas Rachel Lowe Carl A B Pearson Sebastian Funk Alicia Rosello Gwenan M Knight Nikos I Bosse Simon R Procter Georgia R Gore-Langton Alicia Showering James D Munday Katharine Sherratt Thibaut Jombart Emily S Nightingale Yang Liu Christopher I Jarvis Graham Medley Oliver Brady Hamish P Gibbs David Simons Jack Williams Damien C Tully Stefan Flasche Sophie R Meakin Kevin Zandvoort Fiona Y Sun Mark Jit Petra Klepac Matthew Quaife Rosalind M Eggo Frank G Sandmann Akira Endo Kiesha Prem Sam Abbott Rosanna Barnard Yung-Wai D Chan Megan Auzenbergs Amy Gimma C Julian Villabona-Arenas Nicholas G Davies Quarantine and testing strategies in contact tracing for SARS-CoV-2: a modelling study The Lancet Public Health |
| title | Quarantine and testing strategies in contact tracing for SARS-CoV-2: a modelling study |
| title_full | Quarantine and testing strategies in contact tracing for SARS-CoV-2: a modelling study |
| title_fullStr | Quarantine and testing strategies in contact tracing for SARS-CoV-2: a modelling study |
| title_full_unstemmed | Quarantine and testing strategies in contact tracing for SARS-CoV-2: a modelling study |
| title_short | Quarantine and testing strategies in contact tracing for SARS-CoV-2: a modelling study |
| title_sort | quarantine and testing strategies in contact tracing for sars cov 2 a modelling study |
| url | http://www.sciencedirect.com/science/article/pii/S246826672030308X |
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