ArticleThe Lancet regional health. Western Pacific2022
The impact of contact tracing and testing on controlling COVID-19 outbreak without lockdown in Hong Kong: An observational study.
Article in The Lancet regional health. Western Pacific, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 17 papers.
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Who cites it
17 citing papers in PubMed.
- Factors associated with self-isolating and completing a contact follow-up program: a retrospective analysis of Ontario, Canada's COVID-19 contact tracing initiative.BMC public health · 2025Article
- Article
- Impact of infectious density-induced additional screening and treatment saturation on COVID-19: Modeling and cost-effective optimal control.Infectious Disease Modelling · 2024Article
- Observational
- Evaluating completion rates of COVID-19 contact tracing surveys in New York City.BMC public health · 2024Article
- COVID-19 contact tracing and quarantine policies in the Indo-Pacific Region: A mixed-methods study of experiences of public health professionals.PLOS global public health · 2024Article
- Effects of public-health measures for zeroing out different SARS-CoV-2 variants.Nature communications · 2023Article
- Optimal adaptive nonpharmaceutical interventions to mitigate the outbreak of respiratory infections following the COVID-19 pandemic: a deep reinforcement learning study in Hong Kong, China.Journal of the American Medical Informatics Association : JAMIA · 2023Article
- Effectiveness of and Inequalities in COVID-19 Epidemic Control Strategies in Hungary: A Nationwide Cross-Sectional Study.Healthcare (Basel, Switzerland) · 2023Article
- COVID-19 Contact Tracing as an Indicator for Evaluating a Pandemic Situation: Simulation Study.JMIR public health and surveillance · 2023Article
- Article
- Comparisons of the risk of myopericarditis between COVID-19 patients and individuals receiving COVID-19 vaccines: a population-based study.Clinical research in cardiology : official journal of the German Cardiac Society · 2022Article
- Importation, Local Transmission, and Model Selection in Estimating the Transmissibility of COVID-19: The Outbreak in Shaanxi Province of China as a Case Study.Tropical medicine and infectious disease · 2022Article
- Design, Implementation, and Outcomes of a Volunteer-Staffed Case Investigation and Contact Tracing Initiative at an Urban Academic Medical Center.JAMA network open · 2022Article
- Estimating the generation interval from the incidence rate, the optimal quarantine duration and the efficiency of fast switching periodic protocols for COVID-19.Scientific reports · 2022Article
- The impact of multiple non-pharmaceutical interventions on controlling COVID-19 outbreak without lockdown in Hong Kong: A modelling study.The Lancet regional health. Western Pacific · 2022Article
- Path to normality: Assessing the level of social-distancing measures relaxation against antibody-resistant SARS-CoV-2 variants in a partially-vaccinated population.Computational and structural biotechnology journal · 2022Article
Corrections and comments
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Authors and funding
2 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundMaintaining effective contact tracing to control COVID-19 is challenging. Rapid growth in the number of infected cases can overload tracing and testing capacity, resulting in failure to trace contacts and delays in confirming an infection until after symptom onset (confirmation delay), hence increasing transmissibility. A substantial outbreak in Hong Kong, which was suppressed with non-pharmaceutical interventions (NPIs), provided an opportunity to assess the impact of overloading contact tracing and of efforts to improve its efficiency.
methodsUsing epidemiological-link (epi-link) data, we calculated the probability and duration of confirmation delay for cases with and without an epi-link, among all 3,148 confirmed cases between 5 July and 15 August 2020. Logistic regression was performed to determine the relationship between the number of recently confirmed infections and the probability of confirmation delay for epi-linked (contact-traced) cases. We estimated the impact on this relationship of targeted testing of at-risk groups.
findingsThe probability and duration of confirmation delay were associated with the rise in daily case number during growth of the outbreak. The proportion with confirmation delay among contact-traced cases increased from about
interpretationThe number of recently confirmed infections is an indicator of the load on the contact-tracing system, the consequence of which can be assessed by the probability of confirmation delay. Measures to monitor and improve contact-tracing efficiency, alongside social distancing interventions, can enable outbreaks to be controlled without lockdown.
fundingCity University of Hong Kong and Health and Medical Research Fund.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.