Contact tracing is an imperfect tool for controlling COVID-19 transmission and relies on population adherence

Davis, Emma L; Lucas, Tim; Borlase, Anna; Pollington, Timothy M.; Abbott, Sam; Ayabina, Diepreye; Crellen, Thomas; Hellewell, Joel; Pi, Li; Lowe, Rachel; Endo, Akira; Davies, Nicholas; Gore-Langton, Georgia R.; Russell, Timothy; Bosse, Nikos I.; Quaife, Matthew; Kucharski, Adam J.; Nightingale, Emily; Pearson, Carl A. B.; Gibbs, Hamish; O’Reilly, Kathleen; Jombart, Thibaut; Rees, Eleanor M.; Deol, Arminder K.; Hué, Stéphane; Auzenbergs, Megan; Houben, Rein M. G. J.; Funk, Sebastian; Li, Yang; Sun, Fiona Yueqian; Prem, Kiesha; Quilty, Billy J; Villabona-Arenas, Julian; Barnard, Rosanna C.; Hodgson, David; Foss, Anna M; Jarvis, Christopher; Meakin, Sophie; Eggo, Rosalind M; Abbas, Kaja; Zandvoort, Kevin van; Emery, Jon C; Tully, Damien C.; Sandmann, Frank; Edmunds, W. John; Gimma, Amy; Knight, Gwen; Munday, James D.; Diamond, Charlie; Jit, Mark; Leclerc, Quentin J.; Roselló, Alicia; Chan, Yung-Wai Desmond; Simons, David; Clifford, Sam; Flasche, Stefan; Procter, Simon R.; Atkins, Katherine E.; Medley, Graham F.; Hollingsworth, T. Déirdre; Klepac, Petra

doi:10.1038/s41467-021-25531-5

Cited by 47 publications

(49 citation statements)

References 32 publications

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“…The reporting of contacts was primarily through self-reporting, which has typically been shown to be a under estimation of true contacts. 39 During the period of study, there was a significant change in the number of participants who were fully vaccinated. However, it would appear rates of COVID-19 across the course of the season were not particularly skewed to the beginning or the end of the season.…”

Section: Resultsmentioning

confidence: 99%

Risk assessment and implementation of risk reduction measures is not associated with increased transmission of SARS-CoV-2 compared with standard isolation at professional golf events

Robinson

Murray

Watson³

et al. 2022

BMJ Open Sport Exerc Med

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ObjectivesThe purpose of this prospective study was to report incidence and transmission of SARS-CoV-2, among professional golfers and essential support staff undergoing risk assessment and enhanced risk reduction measures when considered a close contact as opposed to standard isolation while competing on the DP World Tour during the 2021 season.MethodsThis prospective cohort study included all players and essential support staff participating in 26 DP World Tour events from 18 April 2021 to 21 November 2021. High-risk contacts were isolated for 10 days. Moderate-risk contacts received education regarding enhanced medical surveillance, had daily rapid antigen testing for 5 days, with reverse transcriptase-polymerase chain reaction (RT-PCR) tesing on day 5, mandated mask use and access to outside space for work purposes only. Low-risk contacts typically received rapid antigen testing every 48 hours and RT-PCR testing on day 5.ResultsThe total study cohort compromised 13 394 person-weeks of exposure. There were a total of 30 positive cases over the study period. Eleven contacts were stratified as ‘high risk’. Two of these subsequently tested positive for SARS-CoV-2. There were 79 moderate-risk contact and 73 low-risk contacts. One moderate-risk contact subsequently tested positive for SARS-CoV-2 but did not transmit the virus. All other contacts, remained negative and asymptomatic to the end of the tournament week.ConclusionsA risk assessment and risk reduction-based approach to contact tracing was safe in this professional golf event setting when Alpha and Delta were the predominant variants. It enabled professional golfers and essential support staff to work.

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Section: Resultsmentioning

confidence: 99%

Risk assessment and implementation of risk reduction measures is not associated with increased transmission of SARS-CoV-2 compared with standard isolation at professional golf events

Robinson

Murray

Watson³

et al. 2022

BMJ Open Sport Exerc Med

View full text Add to dashboard Cite

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“…TTI intervention effectiveness is sensitive to the proportion of symptomatic cases who go on to isolate and test [7, 70, 16]. These actions depend upon recognition of which symptoms are intended to prompt this behaviour and are a key parameter in modelling of symptomatic testing strategies.…”

Section: Reflections On Implications For Modellingmentioning

confidence: 99%

“…Some of the findings have implications for the structure and types of models used to investigate the effectiveness of TTI policies, while others inform likely parameter ranges or distributions, the choice of which has been shown to be one of the main factors in estimation of TTI impact [70]. In some cases, findings help to inform likely trade-offs that models could be employed to investigate, as was done in a previous analysis of the potential effects of mandated isolation depending on how this affected testing behaviour [16].…”

Section: Reflections On Implications For Modellingmentioning

confidence: 99%

“…Children have different main symptoms to adults (headache, rhinorrhoea and fatigue) [69], and it is possible this is also a point of confusion. TTI intervention effectiveness is sensitive to the proportion of symptomatic cases who go on to isolate and test [7,70,16]. These actions depend upon recognition of which symptoms are intended to prompt this behaviour and are a key parameter in modelling of symptomatic testing strategies.…”

Section: Informing Tti Engagement Estimates Chosen In Model Parameter...mentioning

confidence: 99%

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Public perceptions and interactions with UK COVID-19 Test, Trace and Isolate policies, and implications for pandemic infectious disease modelling

Marshall

Skeva

Jay

et al. 2022

Preprint

Self Cite

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The efforts to contain SARS-CoV-2 and reduce the impact of COVID-19 have been supported by Test, Trace and Isolate (TTI) systems in many settings, including the United Kingdom. The mathematical models underlying policy decisions about TTI make assumptions about behaviour in the context of a rapidly unfolding and changeable emergency. This study investigates the reported behaviours of UK citizens in July 2021, assesses them against how a set of TTI processes are conceptualised and represented in models and then interprets the findings with modellers who have been contributing evidence to TTI policy. We report on testing practices, including the uses of and trust in different types of testing, and the challenges of testing and isolating faced by different demographic groups. The study demonstrates the potential of input from members of the public to benefit the modelling process, from guiding the choice of research questions, influencing choice of model structure, informing parameter ranges and validating or challenging assumptions, to highlighting where model assumptions are reasonable or where their poor reflection of practice might lead to uninformative results. We conclude that deeper engagement with members of the public should be integrated at regular stages of public health intervention modelling.

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“…The effectiveness of case isolation and quarantine also depends on the proportion of exposed that are timely reached by contact tracing [8]. While efficient operation of municipal outbreak investigation is crucial, the success of contact tracing is ultimately affected by the willingness of the public to react at SARS-CoV-2 like symptoms and to adhere to isolation and quarantine rules [10].…”

Section: Introductionmentioning

confidence: 99%

Efficacy and effectiveness of case isolation and quarantine during a growing phase of the COVID-19 epidemic in Finland

Auranen

Shubin

Erra³

et al. 2022

Preprint

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Based on data collected as part of the contact tracing activity of the City of Helsinki Epidemiological Operations Unit, we evaluated the efficacy and effectiveness of isolating SARS-CoV-2 cases and quarantining their exposed contacts during a mildly growing phase of the COVID-19 epidemic in Finland in autumn 2020. Based on the observed symptom-to-symptom intervals in 1016 pairs of primary and secondary cases, we estimated that without case isolation or quarantine 40% (90% credible interval, CI 25-59) of transmission would have occurred on the day of or after symptom onset. One third of SARS-CoV-2 cases (N =1521) had initially been quarantined, with a self-reported time until isolation (quarantine) of 0.8 days before symptom onset. This delay translates into an efficacy of 50% (90% CI 40-63) of averting secondary infections per quarantined case. Due to later isolation (mean 2.6 days after symptoms), the efficacy was smaller (24%; 90% CI 12-41) in those two third of the cases (N =3101) whose isolation was prompted by their symptoms, i.e. without being previously quarantined. At the population level, we evaluated the effectiveness of case isolation and quarantine on the growth rate of the COVID-19 epidemic in the autumn of 2020. Under a wide range of underlying assumptions, the rate would have been at least 2 times higher without case isolation and quarantine. The numbers needed to isolate or quarantine to prevent one secondary case were 2 and 20, respectively.

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Contact tracing is an imperfect tool for controlling COVID-19 transmission and relies on population adherence

Cited by 47 publications

References 32 publications

Risk assessment and implementation of risk reduction measures is not associated with increased transmission of SARS-CoV-2 compared with standard isolation at professional golf events

Risk assessment and implementation of risk reduction measures is not associated with increased transmission of SARS-CoV-2 compared with standard isolation at professional golf events

Public perceptions and interactions with UK COVID-19 Test, Trace and Isolate policies, and implications for pandemic infectious disease modelling

Efficacy and effectiveness of case isolation and quarantine during a growing phase of the COVID-19 epidemic in Finland

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