Modelling the impact of travel restrictions on COVID-19 cases in Hong Kong in early 2020

AbstractBackgroundCoronavirus Disease 2019 (COVID-19) led to pandemic that affected almost all countries in the world. Many countries have implemented border restriction as a public health measure to limit local outbreak. However, there is inadequate scientific data to support such a practice, especially in the presence of an established local transmission of the disease.MethodA novel metapopulation Susceptible-Exposed-Infectious-Recovered (SEIR) model with inspected migration was applied to investigate the effect of border restriction between Hong Kong and mainland China on the epidemiological characteristics of COVID-19 in Hong Kong. Isolation facilities occupancy was also studied.ResultsAt R0 of 2·2, the cumulative COVID-19 cases in Hong Kong can be reduced by 13·99% (from 29,163 to 25,084) with complete border closure. At an in-patient mortality of 1·4%, the number of deaths can be reduced from 408 to 351 (57 lives saved). However, border closure alone was insufficient to prevent full occupancy of isolation facilities in Hong Kong; effective public health measures to reduce local R0 to below 1·6 was necessary.ConclusionAs a public health measure to tackle COVID-19, border restriction is effective in reducing cumulative cases and mortality.Article summaryStrengths and limitations of this studyA novel metapopulation SEIR model with inspected migration was developed to investigate the epidemiological characteristics of COVID-19 in Hong Kong, Guangdong and the rest of China (excluding Hubei) in the presence or absence of border restriction.The presented model is also suitable for further analysis of other emerging infectious diseases.Border restriction is an effective public health measure in reducing cumulative cases and mortality for COVID-19.Interaction was assumed to be well-mixed within patch. The spatial effect in disease transmission within each patch is ignored, which can have a non-trivial effect on the dynamic of infectious disease.The proposed model is deterministic in nature which ignores the randomness in migration and in the interactions among people; a stochastic model would be more realistic especially early in the disease.

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Impact of Travel Ban Implementation on COVID-19 Spread in Singapore, Taiwan, Hong Kong and South Korea During the Early Phase of the Pandemic: a Comparative Study.

10.21203/rs.3.rs-248522/v1 ◽

2021 ◽

Author(s):

Sylvia Xiao Wei Gwee ◽

Pearleen Chua Ee Yong ◽

Min Xian Wang ◽

Junxiong Pang

Keyword(s):

Hong Kong ◽

South Korea ◽

Rate Of Change ◽

The Other ◽

Response Data ◽

Travel Restrictions ◽

Imported Cases ◽

Almost All ◽

The Impact ◽

Local Transmission

Abstract Introduction: Since January 2020, the COVID-19 pandemic has elicited imposition of some form of travel restrictions by almost all countries in the world. Most of which persist to this day even as some restrictions have been gradually eased. It remains unclear if the trade-off from the unprecedented disruption to air travel was well worth in the course of pandemic containment.Methods: A comparative analysis was conducted on Singapore, Taiwan, Hong Kong and South Korea’s COVID-19 response. Data on COVID-19 cases, travel-related and community interventions, socio-economic profile were consolidated. Trends on imported and local cases were analyzed using computations of moving averages, rate of change, particularly in response to distinct waves of travel-related interventions due to the outbreak in China, South Korea, Iran & Italy, and Europe.Findings: South Korea’s travel restrictions consistently lagged in terms of timeliness and magnitude. The first wave of travel restrictions against China was implemented 34 days after the outbreak in Wuhan, compared to 22-26 days taken by Singapore, Taiwan and Hong Kong. Restrictions against all countries came after 91 days, compared to 78-80 days for the other three countries. Taiwan and Hong Kong were the most efficient in adopting travel restrictions. Singapore’s belated measures and higher importation risk as compared to the other three Asian countries manifested in its deteriorating local transmission. The rate of change of imported cases fell by 1.08-1.43 across all four countries following the first wave of intervention against China, and by 0.22-0.52 in all countries except South Korea in the fifth wave against all international travellers. Conclusion: Travel restriction was effective in preventing COVID-19 case importation in early outbreak phase. However, evidence of its effect on local transmission was lacking. The impact of travel restrictions in containing epidemics cannot be disentangled from local non-pharmaceutical interventions concurrently implemented. Overall, measures should be complementary, with more emphasis on the latter to contain the outbreak effectively.

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Estimating Force of Infection from Serologic Surveys with Imperfect Tests

10.1101/2020.06.09.20125724 ◽

2020 ◽

Author(s):

Neal Alexander ◽

Mabel Carabali ◽

Jacqueline K Lim

Keyword(s):

Public Health ◽

Public Health Measure ◽

Important Public Health ◽

Control Programs ◽

Force Of Infection ◽

Belief Elicitation ◽

Health Measure ◽

Serological Studies ◽

Using Data ◽

The Impact

The force of infection, or the rate at which susceptible individuals become infected, is an important public health measure for assessing the extent of outbreaks and the impact of control programs. Here we present methods for estimating force of infection from serological surveys of infections which produce lasting immunity, taking into account imperfections in the test used, and uncertainty in such imperfections. The methods cover both single serological surveys, in which age is a proxy for time at risk, and repeat surveys in the same people, in which the force of infection is estimated more directly. Fixed values can be used for the sensitivity and specificity of the tests, or existing methods for belief elicitation can be used to include uncertainty in these values. The latter may be applicable, for example, when the specificity of a test depends on co-circulating pathogens, which may not have been well characterized in the setting of interest. We illustrate the methods using data from two published serological studies of dengue.

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Impact of travel ban implementation on COVID-19 spread in Singapore, Taiwan, Hong Kong and South Korea during the early phase of the pandemic: A comparative study.

10.21203/rs.3.rs-248522/v2 ◽

2021 ◽

Author(s):

Sylvia Xiao Wei Gwee ◽

Pearleen Chua Ee Yong ◽

Min Xian Wang ◽

Junxiong Pang

Keyword(s):

Hong Kong ◽

South Korea ◽

Rate Of Change ◽

The Other ◽

Response Data ◽

Travel Restrictions ◽

Imported Cases ◽

Almost All ◽

The Impact ◽

Local Transmission

Abstract Introduction: Since January 2020, the COVID-19 pandemic has elicited imposition of some form of travel restrictions by almost all countries in the world. Most of which persist to this day even as some restrictions have been gradually eased. It remains unclear if the trade-off from the unprecedented disruption to air travel was well worth in the course of pandemic containment.Methods: A comparative analysis was conducted on Singapore, Taiwan, Hong Kong and South Korea’s COVID-19 response. Data on COVID-19 cases, travel-related and community interventions, socio-economic profile were consolidated. Trends on imported and local cases were analyzed using computations of moving averages, rate of change, particularly in response to distinct waves of travel-related interventions due to the outbreak in China, South Korea, Iran & Italy, and Europe.Findings: South Korea’s travel restrictions consistently lagged in terms of timeliness and magnitude. The first wave of travel restrictions against China was implemented 34 days after the outbreak in Wuhan, compared to 22-26 days taken by Singapore, Taiwan and Hong Kong. Restrictions against all countries came after 91 days, compared to 78-80 days for the other three countries. Taiwan and Hong Kong were the most efficient in adopting travel restrictions. Singapore’s belated measures and higher importation risk as compared to the other three Asian countries manifested in its deteriorating local transmission. The rate of change of imported cases fell by 1.08-1.43 across all four countries following the first wave of intervention against China, and by 0.22-0.52 in all countries except South Korea in the fifth wave against all international travellers. Conclusion: Travel restriction was effective in preventing COVID-19 case importation in early outbreak phase. However, evidence of its effect on local transmission was lacking. The impact of travel restrictions in containing epidemics cannot be disentangled from local non-pharmaceutical interventions concurrently implemented. Overall, measures should be complementary, with more emphasis on the latter to contain the outbreak effectively.

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Impact of travel ban implementation on COVID-19 spread in Singapore, Taiwan, Hong Kong and South Korea during the early phase of the pandemic: a comparative study

BMC Infectious Diseases ◽

10.1186/s12879-021-06449-1 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Sylvia Xiao Wei Gwee ◽

Pearleen Ee Yong Chua ◽

Min Xian Wang ◽

Junxiong Pang

Keyword(s):

Hong Kong ◽

South Korea ◽

Rate Of Change ◽

Response Data ◽

Travel Restrictions ◽

Imported Cases ◽

Economic Profile ◽

Almost All ◽

The Impact ◽

Travel Restriction

Abstract Background The COVID-19 pandemic has elicited imposition of some form of travel restrictions by almost all countries in the world. Most restrictions currently persist, although some have been gradually eased. It remains unclear if the trade-off from the unprecedented disruption to air travel was well worth for pandemic containment. Method A comparative analysis was conducted on Singapore, Taiwan, Hong Kong and South Korea’s COVID-19 response. Data on COVID-19 cases, travel-related and community interventions, socio-economic profile were consolidated. Trends on imported and local cases were analyzed using computations of moving averages, rate of change, particularly in response to distinct waves of travel-related interventions due to the outbreak in China, South Korea, Iran & Italy, and Europe. Results South Korea’s travel restrictions were observed to be consistently more lagged in terms of timeliness and magnitude, with their first wave of travel restrictions on flights departing from China implemented 34 days after the outbreak in Wuhan, compared to 22–26 days taken by Singapore, Taiwan and Hong Kong. South Korea’s restrictions against all countries came after 91 days, compared to 78–80 days for the other three countries. The rate of change of imported cases fell by 1.08–1.43 across all four countries following the first wave of travel restrictions on departures from China, and by 0.22–0.52 in all countries except South Korea in the fifth wave against all international travellers. Delayed rate of change of local cases resulting from travel restrictions imposed by the four countries with intrinsic importation risk, were not observed. Conclusions Travel restriction was effective in preventing COVID-19 case importation in early outbreak phase, but may still be limited in preventing general local transmission. The impact of travel restrictions, regardless of promptness, in containing epidemics likely also depends on the effectiveness of local surveillance and non-pharmaceutical interventions concurrently implemented.

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Coronavirus with “Nobody in Charge”

Regions & Cohesion ◽

10.3167/reco.2020.100201 ◽

2020 ◽

Vol 10 (2) ◽

pp. iv-x

Author(s):

Harlan Koff ◽

Carmen Maganda

Keyword(s):

Public Health ◽

Public Health Measure ◽

Health Measure ◽

Nation States ◽

Travel Restrictions

The Editors’ Note is a space for us to introduce important themes addressed by the articles in each issue of Regions & Cohesion. We will, of course, complete this task. However, before doing so, we take this opportunity to write about our world during the present coronavirus pandemic. Unfortunately, this crisis has forced most nation-states to close their borders as a necessary public health measure. Travel restrictions are regrettable but comprehensible.

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Impact of school closures and re-openings on COVID-19 transmission

Canada Communicable Disease Report ◽

10.14745/ccdr.v47i12a02 ◽

2021 ◽

Vol 47 (12) ◽

pp. 515-523

Author(s):

Maryem El Jaouhari ◽

Rojiemiahd Edjoc ◽

Lisa Waddell ◽

Patricia Houston ◽

Nicole Atchessi ◽

...

Keyword(s):

Public Health ◽

Empirical Studies ◽

Rapid Review ◽

Public Health Measure ◽

School Closures ◽

Health Measures ◽

Health Measure ◽

Education Of Students ◽

Research Criteria ◽

The Impact

Background: Globally, the education of students at primary and secondary schools has been severely disrupted by the implementation of school closures to reduce the spread of coronavirus disease 2019 (COVID-19). The effectiveness of school closures in reducing transmission of COVID-19 and the impact of re-opening schools are unclear. Methods: Research criteria for this rapid review included empirical studies, published or pre-published worldwide before January 25, 2021, that assessed the effectiveness of school closures in reducing the spread of COVID-19 and the impact of school re-openings on COVID-19 transmission. Results: Twenty-four studies on the impact of school closures and re-openings on COVID-19 transmission were identified through the seven databases that were searched. Overall the evidence from these studies was mixed and varied due to several factors such as the time of implementation of public health measures, research design of included studies and variability among the levels of schooling examined. Conclusion: Preliminary findings suggest that school closures have limited impact on reducing COVID-19 transmission, with other non-pharmaceutical interventions considered much more effective. However, due to the limitations of the studies, further research is needed to support the use of this public health measure in response to the COVID-19 pandemic.

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Impact of public health interventions to curb SARS-CoV-2 spread assessed by an evidence-educated Delphi panel and tailored SEIR model

Journal of Public Health ◽

10.1007/s10389-021-01566-2 ◽

2021 ◽

Author(s):

Bernd Brüggenjürgen ◽

Hans-Peter Stricker ◽

Lilian Krist ◽

Miriam Ortiz ◽

Thomas Reinhold ◽

...

Keyword(s):

Public Health ◽

Transmission Rate ◽

Latency Period ◽

Policy Decision ◽

Sensitivity Analyses ◽

Delphi Panel ◽

Time Step ◽

Seir Model ◽

Health Policy Decision ◽

The Impact

Abstract Aim To use a Delphi-panel-based assessment of the effectiveness of different non-pharmaceutical interventions (NPI) in order to retrospectively approximate and to prospectively predict the SARS-CoV-2 pandemic progression via a SEIR model (susceptible, exposed, infectious, removed). Methods We applied an evidence-educated Delphi-panel approach to elicit the impact of NPIs on the SARS-CoV-2 transmission rate R0 in Germany. Effectiveness was defined as the product of efficacy and compliance. A discrete, deterministic SEIR model with time step of 1 day, a latency period of 1.8 days, duration of infectiousness of 5 days, and a share of the total population of 15% assumed to be protected by immunity was developed in order to estimate the impact of selected NPI measures on the course of the pandemic. The model was populated with the Delphi-panel results and varied in sensitivity analyses. Results Efficacy and compliance estimates for the three most effective NPIs were as follows: test and isolate 49% (efficacy)/78% (compliance), keeping distance 42%/74%, personal protection masks (cloth masks or other face masks) 33%/79%. Applying all NPI effectiveness estimates to the SEIR model resulted in a valid replication of reported occurrence of the German SARS-CoV-2 pandemic. A combination of four NPIs at consented compliance rates might curb the CoViD-19 pandemic. Conclusion Employing an evidence-educated Delphi-panel approach can support SARS-CoV-2 modelling. Future curbing scenarios require a combination of NPIs. A Delphi-panel-based NPI assessment and modelling might support public health policy decision making by informing sequence and number of needed public health measures.

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