scholarly journals Impact of public health interventions on the COVID-19 epidemic: a stochastic model based on data from an African island

2020 ◽  
Author(s):  
D. C. Nuckchady
Keyword(s):  
Stochastic Model ◽  
Population Surveillance ◽  
Health Interventions ◽  
Contact Tracing ◽  
Point Of Entry ◽  
Highly Sensitive ◽  
Travel Restrictions ◽  
Community Transmission ◽  
The Impact ◽  
Key Interventions

AbstractA stochastic model was created to simulate the impact of various healthcare measures on the COVID-19 epidemic. Travel restrictions and point of entry or exit screening help to delay the onset of the outbreak by a few weeks. Population surveillance is critical to detect the start of community transmission early and to avoid a surge in cases. Contact reduction and contact tracing are key interventions that can help to control the outbreak. To promptly curb the number of new cases, countries should diagnose patients using a highly sensitive test.

scholarly journals Protective impacts of household-based tuberculosis contact tracing are robust across endemic incidence levels and community contact patterns

2021 ◽  
Vol 17 (2) ◽  
pp. e1008713 ◽  
Author(s):  
Joshua Havumaki ◽  
Ted Cohen ◽  
Chengwei Zhai ◽  
Joel C. Miller ◽  
Seth D. Guikema ◽  
...  
Keyword(s):  
Population Level ◽  
Contact Tracing ◽  
Spatially Explicit Model ◽  
Household Transmission ◽  
Contact Patterns ◽  
Social Mixing ◽  
High Incidence ◽  
Community Transmission ◽  
The Impact ◽  
The Relationship

There is an emerging consensus that achieving global tuberculosis control targets will require more proactive case finding approaches than are currently used in high-incidence settings. Household contact tracing (HHCT), for which households of newly diagnosed cases are actively screened for additional infected individuals is a potentially efficient approach to finding new cases of tuberculosis, however randomized trials assessing the population-level effects of such interventions in settings with sustained community transmission have shown mixed results. One potential explanation for this is that household transmission is responsible for a variable proportion of population-level tuberculosis burden between settings. For example, transmission is more likely to occur in households in settings with a lower tuberculosis burden and where individuals mix preferentially in local areas, compared with settings with higher disease burden and more dispersed mixing. To better understand the relationship between endemic incidence levels, social mixing, and the impact of HHCT, we developed a spatially explicit model of coupled household and community transmission. We found that the impact of HHCT was robust across settings of varied incidence and community contact patterns. In contrast, we found that the effects of community contact tracing interventions were sensitive to community contact patterns. Our results suggest that the protective benefits of HHCT are robust and the benefits of this intervention are likely to be maintained across epidemiological settings.

scholarly journals Impact of lockdown measures in abating the COVID-19 pandemic: Lessons from India’s phased approach

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
R Singh ◽  
K Sharma
Keyword(s):  
Public Health ◽  
World Health ◽  
The Public ◽  
Daily Data ◽  
Travel Restrictions ◽  
Community Transmission ◽  
The Government ◽  
Novel Coronavirus ◽  
Health Organization ◽  
The Impact

Abstract Background World Health Organization (WHO) declared that the outbreak of novel coronavirus (2019-nCoV) constituted a Public Health Emergency of International Concern (PHEIC) on 30 January 2020 and characterized the novel coronavirus disease (COVID-19) as a pandemic on 11 March 2020. India enacted such measures early on for effective mitigation and suppression to reduce community transmission, including an onerous national lockdown. The impact of the health system governance is quite apparent among all stakeholders including the public in such emergency contexts. Methods We compiled the daily data on the number of COVID-19 cases, recoveries and deaths from January 30th until June 16th, 2020. Different stages were categorized from post PHEIC declaration (pre-lockdown) phase to lockdown phases and unlocking phase as implemented. The several measures adopted by the national government were structured in four broad categories as Governance and socioeconomic, travel restrictions, lockdown and public health measures. These measures were compared during each phase. Results It was revealed that while the cases are rising the phased restrictions has helped in delaying the peak and remarkably interrupted the rate of transmission. The national average doubling rate was 3 days at the beginning which improved to 22 days. The basic reproduction number remained close to 1 during the last week of lockdown. However, the initial interruption of needed aid and technical support had negative social and economic impacts on the affected population. Conclusions As the situation abates following the measures adopted by the government, an articulate strategy of unlocking through increased testing and prompt isolation needs to be developed for more effective reduction and protecting the livelihoods allowing to further relax the lockdown measures. Key messages There is need for the local government to consider a strategic easing of the lockdown for protecting the rights of the most affected population. As the transmission rates are low, the easing of lockdown can be benefited from improved testing and prompt isolation.

scholarly journals The Impact of Universal Mask Use on SARS-COV-2 in Victoria, Australia on the Epidemic Trajectory of COVID-19

2021 ◽  
Vol 9 ◽  
Author(s):  
Valentina Costantino ◽  
Chandini Raina MacIntyre
Keyword(s):  
Mathematical Modeling ◽  
Deterministic Model ◽  
Face Mask ◽  
Control Measures ◽  
Contact Tracing ◽  
Epidemic Size ◽  
Community Transmission ◽  
Age Structured ◽  
The Impact ◽  
Mask Effectiveness

Objective(s): To estimate the impact of universal community face mask use in Victoria, Australia along with other routine disease control measures in place.Methods: A mathematical modeling study using an age structured deterministic model for Victoria, was simulated for 123 days between 1 June 2020 and 1 October 2020, incorporating lockdown, contact tracing, and case findings with and without mask use in varied scenarios. The model tested the impact of differing scenarios of the universal use of face masks in Victoria, by timing, varying mask effectiveness, and uptake.Results: A six-week lockdown with standard control measures, but no masks, would have resulted in a large resurgence by September, following the lifting of restrictions. Mask use can substantially reduce the epidemic size, with a greater impact if at least 50% of people wear a mask which has an effectiveness of at least 40%. Early mask use averts more cases than mask usage that is only implemented closer to the peak. No mask use, with a 6-week lockdown, results in 67,636 cases and 120 deaths by 1 October 2020 if no further lockdowns are used. If mask use at 70% uptake commences on 23 July 2020, this is reduced to 7,961 cases and 42 deaths. We estimated community mask effectiveness to be 11%.Conclusion(s): Lockdown and standard control measures may not have controlled the epidemic in Victoria. Mask use can substantially improve epidemic control if its uptake is higher than 50% and if moderately effective masks are used. Early mask use should be considered in other states if community transmission is present, as this has a greater effect than later mask wearing mandates.

scholarly journals Estimating COVID Risk During a Period of Pandemic Decline

2021 ◽  
Vol 9 ◽  
Author(s):  
Timothy J. J. Inglis ◽  
Benjamin McFadden ◽  
Anthony Macali
Keyword(s):  
Public Health ◽  
Real Time ◽  
Health Resources ◽  
Risk Estimate ◽  
Contact Tracing ◽  
Business Continuity ◽  
Risk Monitoring ◽  
Open Source Data ◽  
Travel Restrictions ◽  
Community Transmission

Background: Many parts of the world that succeeded in suppressing epidemic coronavirus spread in 2020 have been caught out by recent changes in the transmission dynamics of SARS-CoV-2. Australia's early success in suppressing COVID-19 resulted in lengthy periods without community transmission. However, a slow vaccine rollout leaves this geographically isolated population vulnerable to leakage of new variants from quarantine, which requires internal travel restrictions, disruptive lockdowns, contact tracing and testing surges.Methods: To assist long term sustainment of limited public health resources, we sought a method of continuous, real-time COVID-19 risk monitoring that could be used to alert non-specialists to the level of epidemic risk on a sub-national scale. After an exploratory data assessment, we selected four COVID-19 metrics used by public health in their periodic threat assessments, applied a business continuity matrix and derived a numeric indicator; the COVID-19 Risk Estimate (CRE), to generate a daily spot CRE, a 3 day net rise and a seven day rolling average. We used open source data updated daily from all Australian states and territories to monitor the CRE for over a year.Results: Upper and lower CRE thresholds were established for the CRE seven day rolling average, corresponding to risk of sustained and potential outbreak propagation, respectively. These CRE thresholds were used in a real-time map of Australian COVID-19 risk estimate distribution by state and territory.Conclusions: The CRE toolkit we developed complements other COVID-19 risk management techniques and provides an early indication of emerging threats to business continuity.

scholarly journals Modelling the impact of reducing control measures on the COVID-19 pandemic in a low transmission setting

2020 ◽  
Author(s):  
Nick Scott ◽  
Anna Palmer ◽  
Dominic Delport ◽  
Romesh Abeysuriya ◽  
Robyn Stuart ◽  
...  
Keyword(s):  
Public Transport ◽  
Risk Mitigation ◽  
Mitigation Strategies ◽  
Control Measures ◽  
Contact Tracing ◽  
Policy Changes ◽  
Low Transmission ◽  
Transmission Setting ◽  
Community Transmission ◽  
The Impact

AbstractAimsWe assessed COVID-19 epidemic risks associated with relaxing a set of physical distancing restrictions in the state of Victoria, Australia – a setting with low community transmission – in line with a national framework that aims to balance sequential policy relaxations with longer-term public health and economic need.MethodsAn agent-based model, Covasim, was calibrated to the local COVID-19 epidemiological and policy environment. Contact networks were modelled to capture transmission risks in households, schools and workplaces, and a variety of community spaces (e.g. public transport, parks, bars, cafes/restaurants) and activities (e.g. community or professional sports, large events). Policy changes that could prevent or reduce transmission in specific locations (e.g. opening/closing businesses) were modelled in the context of interventions that included testing, contact tracing (including via a smartphone app), and quarantine.ResultsPolicy changes leading to the gathering of large, unstructured groups with unknown individuals (e.g. bars opening, increased public transport use) posed the greatest risk, while policy changes leading to smaller, structured gatherings with known individuals (e.g. small social gatherings) posed least risk. In the model, epidemic impact following some policy changes took more than two months to occur. Model outcomes support continuation of working from home policies to reduce public transport use, and risk mitigation strategies in the context of social venues opening, such as >30% population-uptake of a contact-tracing app, physical distancing policies within venues reducing transmissibility by >40%, or patron identification records being kept to enable >60% contact tracing.ConclusionsIn a low transmission setting, care should be taken to avoid lifting sequential COVID-19 policy restrictions within short time periods, as it could take more than two months to detect the consequences of any changes. These findings have implications for other settings with low community transmission where governments are beginning to lift restrictions.

scholarly journals Modelling digital and manual contact tracing for COVID-19 Are low uptakes and missed contacts deal-breakers?

2021 ◽  
Author(s):  
Andrei Rusu ◽  
Katayoun Farrahi ◽  
Rémi Emonet
Keyword(s):  
Public Health ◽  
Mean Field ◽  
Epidemiological Model ◽  
Health Interventions ◽  
Contact Tracing ◽  
Public Health Interventions ◽  
Fair Proportion ◽  
Usage Patterns ◽  
The Right ◽  
The Impact

ABSTRACTComprehensive testing schemes, followed by adequate contact tracing and isolation, represent the best public health interventions we can employ to reduce the impact of an ongoing epidemic when no or limited vaccines are available and the implications of a full lockdown are to be avoided. However, the process of tracing can prove feckless for highly-contagious viruses such as SARS-Cov-2. The interview-based approaches often miss contacts and involve significant delays, while digital solutions can suffer from insufficient adoption rates or inadequate usage patterns. Here we present a novel way of modelling different contact tracing strategies using a generalized multi-site mean-field model, which can naturally assess the impact of both manual and digital approaches. Our methodology can readily be applied to any compartmental formulation, thus enabling the study of several complex pathogens. We use this technique to simulate a new epidemiological model, SEIR-T, and show that, given the right conditions, tracing in a COVID-19 epidemic can be effective even when digital uptakes are sub-optimal or interviewers miss a fair proportion of the contacts.

scholarly journals The impact of lockdown measures on COVID-19: a worldwide comparison

2020 ◽  
Author(s):  
DI Papadopoulos ◽  
I Donkov ◽  
K Charitopoulos ◽  
S Bishara
Keyword(s):  
Public Information ◽  
Reproductive Rate ◽  
International Travel ◽  
School Closure ◽  
Contact Tracing ◽  
Economic Implications ◽  
Information Campaigns ◽  
Early Introduction ◽  
Travel Restrictions ◽  
The Impact

AbstractObjectiveWe aimed to determine which aspects of the COVID-19 national response are independent predictors of COVID-19 mortality and case numbers.DesignComparative observational study between nations using publicly available data.SettingWorldwide Participants Covid-19 patientsInterventionsStringency of 11 lockdown policies recorded by the Blavatnik School of Government database and earliness of each policy relative to first recorded national casesMain outcome measuresAssociation with log10 National deaths (LogD) and log10 National cases (LogC) on the 29th April 2020 corrected for predictive demographic variablesResultsEarly introduction was associated with reduced mortality (n=137) and case numbers (n=150) for every policy aside from testing policy, contact tracing and workplace closure. Maximum policy stringency was only found to be associated with reduced mortality (p=0·003) or case numbers (p=0·010) for international travel restrictions. A multivariate model, generated using demographic parameters (r2=0·72 for LogD and r2=0·74 for LogC), was used to assess the timing of each policy. Early introduction of first measure (significance p=0·048, regression coefficient β=-0·004, 95% confidence interval 0 to -0·008), early international travel restrictions (p=0·042, β=-0·005, -0·001 to - 0·009) and early public information (p=0·021, β=-0·005, -0·001 to -0·009) were associated with reduced LogC. Early introduction of first measure (p=0·003, β=-0·007, -0·003 to -0·011), early international travel restrictions (p=0·003, β=-0·008, -0·004 to-0·012), early public information (p=0·003, β=-0·007, 0·003 to -0·011), early generalised workplace closure (p=0·031, β=-0·012, -0·002 to -0·022) and early generalised school closure (p=0·050, β=-0·012, 0 to -0·024) were associated with reduced LogC.ConclusionsAt this stage in the pandemic, early institution of public information, international travel restrictions, and workplace closure are associated with reduced COVID-19 mortality and maintaining these policies may help control the pandemic.What is already known on this topicThe COVID-19 pandemic has spread rapidly throughout the world and presented vast healthcare, economic and political challenges. Many nations have recently passed the peak of their infection rate, and are weighing up relaxation of lockdown strategies. Though the effect of individual lockdown policies can be estimated by modelling, little is known about the impact of individual policies on population case numbers or mortality through comparison of differing strategies between nations. A PubMed search was carried out on the 14/5/20 using keywords including “novel coronavirus-infected pneumonia”, “2019-nCoV”, “Sars-Cov-2”, “Covid-19”, “lockdown”,” policy”, “social distancing”, “isolation”, “quarantine” and “contact tracing” returned 258 studies in total. Following scanning of the above results, we found 19 studies that have examined the effect of lockdown within a region, which have demonstrated a reduction in case numbers after the introduction of a lockdown. There are no previous studies that have compared the effectiveness of government lockdowns between nations to determine the effectiveness of specific policies.What this study addsThis study examines the corollary between government policy and COVID-19 case numbers and mortality, correct as of the 29th of April 2020, for every nation that there is available date within the Blavatnik School of Government database on COVID-19 policy. The study demonstrates that early generalised school closure, early generalised workplace closure, early restriction of international travel and early public information campaigns are independently associated with reduced national COVID-19 mortality. The maximum stringency of individual lockdown policies were not associated with reduced case numbers or mortality. Early reintroduction of these policies may be most effective in a relapse of the pandemic, though, school closure, workplace closure and restriction of international travel carry heavy politico-economic implications. There was no measurable effect of maximum stringency of lockdown policy on outcome at this point in time, indicating that early timing of lockdown introduction is of greater importance than its stringency, provided that the resultant viral reproductive rate is less than 1.

scholarly journals A Model Based Analysis for COVID-19 Pandemic in India: Implications for Health Systems and Policy for Low- and Middle-Income Countries

2020 ◽  
Author(s):  
Shankar Prinja ◽  
Pankaj Bahuguna ◽  
Yashika Chugh ◽  
Anna Vassall ◽  
Arvind Pandey ◽  
...  
Keyword(s):  
Public Health ◽  
Health System ◽  
Air Travel ◽  
Contact Tracing ◽  
System Response ◽  
Middle Income ◽  
Middle Income Countries ◽  
Health Measures ◽  
Travel Restrictions ◽  
The Impact

AbstractBackgroundOur analysis aims to model COVID-19 pandemic in India, potential impact of various measures, along with assessment of health system preparedness and cost to manage the epidemic.MethodsWe developed a susceptible-exposed-infectious-recovered (SEIR) mathematical model to predict the health outcomes under an unmitigated scenario which comprises of air travel restrictions alone, and the current scenario consisting of air travel restrictions along with 8-week lockdown. In addition, we also evaluate the effectiveness of 8-week lockdown along with intensified public health measures at varying level of effectiveness. We assessed the impact of these interventions on COVID-19 related health outcomes in comparison to the unmitigated scenario. Next, we ascertain the need for augmenting infrastructure and the costs of COVID-19 management in India.FindingsIn the event of a lockdown for 8 weeks, the peak of the epidemic shifts by 34-76 days, and the number of cases at the end of 8-week lockdown reduces by 69% to 97% with varying effectiveness of lockdown. However, the cumulative long-term cases remain the same. Intensification of public health surveillance measures with 60% effectiveness is estimated to reduce the cases at peak and cumulative number of infections by 70% and 26.6% respectively. The requirement of ICU beds and ventilators would reduce by 83% with intensified public health measures. The cost of managing COVID-19 in India is nearly 4.5% of the gross domestic product (GDP) in the absence of any intervention which increases to 6.2% with intensified public health measures for COVID-19 response.ConclusionLockdown measures delay the onset of peak, and give much needed time to health system to prepare. Strengthening the public health system response in terms of testing, isolation treatment of cases, and contact tracing needs would lead to significant gains in terms of case load, and meeting health system needs.SummaryWhat is already known?A few studies have been carried out in Indian context to model the epidemic. These models explored the impact of lockdowns and social distancing measures focusing more on the course of the epidemic but none of these evaluated the impact on health system’s response needed as well as the economic impact of COVID-19 management in India. The findings from these studies are limited in a sense that either these studies evaluated the hypothetical scenarios of strategies implemented or focusing to smaller geographical regions in India.What are the new findings?Evidence pertaining to health economic impact of COVID-19 management, in context to Low- and Middle-Income countries, is very limited. To address this, we used the susceptible-exposed-infectious-recovered (SEIR) model to assess:the health system preparedness challenge in terms of hospital beds for isolation, intensive care and ventilators which would be required to manage the epidemic and the economic implications of managing the COVID-19 pandemic in India.the incremental cost of intensified public health measures per infection and per death averted.What do the new finding imply?In India, measures such as lockdowns would certainly delays the onset of peak of COVID-19 epidemic. This would help delay the surge of cases, which would buy time for the health system to prepare. Strengthening the health system response in terms of enhanced testing, isolation of cases, treatment and contact tracing, as is being done currently, would have to be the mainstay to reduce the impact of the pandemic in terms of reduction in infected population and COID-19 deaths in India until vaccine becomes available.

scholarly journals Modelling digital and manual contact tracing for COVID-19. Are low uptakes and missed contacts deal-breakers?

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259969
Author(s):  
Andrei C. Rusu ◽  
Rémi Emonet ◽  
Katayoun Farrahi
Keyword(s):  
Field Model ◽  
Mean Field ◽  
Health Interventions ◽  
Contact Tracing ◽  
Public Health Interventions ◽  
Mean Field Model ◽  
Pathogen Dynamics ◽  
Usage Patterns ◽  
The Right ◽  
The Impact

Comprehensive testing schemes, followed by adequate contact tracing and isolation, represent the best public health interventions we can employ to reduce the impact of an ongoing epidemic when no or limited vaccine supplies are available and the implications of a full lockdown are to be avoided. However, the process of tracing can prove feckless for highly-contagious viruses such as SARS-CoV-2. The interview-based approaches often miss contacts and involve significant delays, while digital solutions can suffer from insufficient adoption rates or inadequate usage patterns. Here we present a novel way of modelling different contact tracing strategies, using a generalized multi-site mean-field model, which can naturally assess the impact of manual and digital approaches alike. Our methodology can readily be applied to any compartmental formulation, thus enabling the study of more complex pathogen dynamics. We use this technique to simulate a newly-defined epidemiological model, SEIR-T, and show that, given the right conditions, tracing in a COVID-19 epidemic can be effective even when digital uptakes are sub-optimal or interviewers miss a fair proportion of the contacts.

scholarly journals Non-Pharmaceutical Interventions in a Generalized Model of Interactive Dynamics Between COVID-19 and The Economy

2021 ◽  
Author(s):  
Soumya Datta ◽  
C. Saratchand
Keyword(s):  
Public Health ◽  
Health Interventions ◽  
Economic Activities ◽  
Public Health Interventions ◽  
Travel Restrictions ◽  
Functional Forms ◽  
Interactive Dynamics ◽  
The Impact ◽  
Pharmaceutical Interventions ◽  
Infection Recurrence

Abstract We use a simple general model of interactive dynamics between the COVID-19 pandemic and the economy to examine the impact of various non-pharmaceutical interventions in the form of restrictions on socio-economic activities like lockdowns, travel restrictions etc. We mathematically demonstrate that these restrictions might be useful in preventing repeated waves of infection recurrence in the pandemic. These results are general and not dependent on choice of specific functional forms or parameter configurations. We set out briefly the implications of these results for public health interventions.

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