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Suppressing COVID-19 Transmission in Hong Kong: An Observational Study of the First Four Months
55 Pages Posted: 5 Aug 2020
More...Abstract
Background: Hong Kong was one of the first locations outside of mainland China to identify COVID-19 cases in January 2020. We assessed the impact of various public health measures on transmission.
Methods: We analysed data on all COVID-19 cases and public health measures in Hong Kong up to 7 May 2020. We described case-based, travel-based and community-based measures and examined their potential effects on case identification and transmission. Changes in transmissibility measured by the effective reproductive number R t were estimated by comparing the R t between periods when public health measures were and were not in effect. Delays in case confirmation in imported cases and locally infected cases were analysed to indicate the possible impact of expansion of laboratory testing capacity.
Findings: Introduction of a 14-day quarantine on persons arriving from affected areas was associated with a 95% reduction in transmissibility from imported cases. Testing all arriving travelers reduced mean delays between arrival and detection of imported cases. Increases in laboratory testing capacity for pneumonia inpatients and symptomatic outpatients reduced the delay from onset to confirmation. Working from home and physical distancing measures implemented in high-risk facilities were associated with 67% and 58% reduction in transmission of COVID-19, respectively.
Interpretation: Suppression of COVID-19 transmission in the first pandemic wave in Hong Kong was achieved through integration of travel-based, case-based and community-based public health measures focusing on early case identification and isolation and physical distancing.
Funding: This project was supported by the Health and Medical Research Fund, Food and Health Bureau, Government of the Hong Kong Special Administrative Region (grant no. COVID190118), and the Theme-based Research Scheme (Project No. T11-712/19-N] of the Research Grants Council of the Hong Kong SAR Government.
Declaration of Interests: BJC consults for Roche and Sanofi Pasteur. The authors report no other potential conflicts of interest.
Ethics Approval Statement: The project was approved by the Institutional Review Board of the University of Hong Kong.
Keywords: COVID-19; SARS-CoV-2; transmission; intervention; Hong Kong
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