scholarly journals Determining the optimal strategy for reopening schools, work and society in the UK: balancing earlier opening and the impact of test and trace strategies with the risk of occurrence of a secondary COVID-19 pandemic wave

2020 ◽  
Author(s):  
Jasmina Panovska-Griffiths ◽  
Cliff Kerr ◽  
Robyn Margaret Stuart ◽  
Dina Mistry ◽  
Daniel Klein ◽  
...  
Keyword(s):  
Large Scale ◽  
Reproduction Number ◽  
Epidemiological Data ◽  
Contact Tracing ◽  
Cumulative Number ◽  
Social Distancing ◽  
Uk Government ◽  
The Uk ◽  
The Impact ◽  
Pandemic Wave

Background In order to slow down the spread of SARS-CoV-2, the virus causing the COVID-19 pandemic, the UK government has imposed strict physical distancing (lockdown) measures including school 'dismissals' since 23 March 2020. As evidence is emerging that these measures may have slowed the spread of the pandemic, it is important to assess the impact of any changes in strategy, including scenarios for school reopening and broader relaxation of social distancing. This work uses an individual-based model to predict the impact of a suite of possible strategies to reopen schools in the UK, including that currently proposed by the UK government. Methods We use Covasim, a stochastic agent-based model for transmission of COVID-19, calibrated to the UK epidemic. The model describes individuals' contact networks stratified as household, school, work and community layers, and uses demographic and epidemiological data from the UK. We simulate a range of different school reopening strategies with a society-wide relaxation of lockdown measures and in the presence of different non-pharmaceutical interventions, to estimate the number of new infections, cumulative cases and deaths, as well as the effective reproduction number with different strategies. To account for uncertainties within the stochastic simulation, we also simulated different levels of infectiousness of children and young adults under 20 years old compared to older ages. Findings We found that with increased levels of testing of people (between 25% and 72% of symptomatic people tested at some point during an active COVID-19 infection depending on scenarios) and effective contact-tracing and isolation for infected individuals, an epidemic rebound may be prevented across all reopening scenarios, with the effective reproduction number (R) remaining below one and the cumulative number of new infections and deaths significantly lower than they would be if testing did not increase. If UK schools reopen in phases from June 2020, prevention of a second wave would require testing 51% of symptomatic infections, tracing of 40% of their contacts, and isolation of symptomatic and diagnosed cases. However, without such measures, reopening of schools together with gradual relaxing of the lockdown measures are likely to induce a secondary pandemic wave, as are other scenarios for reopening. When infectiousness of <20 year olds was varied from 100% to 50% of that of older ages, our findings remained unchanged. Interpretation To prevent a secondary COVID-19 wave, relaxation of social distancing including reopening schools in the UK must be implemented alongside an active large-scale population-wide testing of symptomatic individuals and effective tracing of their contacts, followed by isolation of symptomatic and diagnosed individuals. Such combined measures have a greater likelihood of controlling the transmission of SARS-CoV-2 and preventing a large number of COVID-19 deaths than reopening schools and society with the current level of implementation of testing and isolation of infected individuals.

scholarly journals A viral perspective on worldwide non-pharmaceutical interventions against COVID-19

2020 ◽  
Author(s):  
Jean-Philippe Rasigade ◽  
Anaïs Barray ◽  
Julie Teresa Shapiro ◽  
Charlène Coquisart ◽  
Yoann Vigouroux ◽  
...  
Keyword(s):  
Large Scale ◽  
Reproduction Number ◽  
Cumulative Effect ◽  
Epidemiological Data ◽  
Time And Space ◽  
Minimal Set ◽  
Genomic Divergence ◽  
The Impact ◽  
Pharmaceutical Interventions

AbstractQuantifying the effectiveness of large-scale non-pharmaceutical interventions (NPIs) against COVID-19 is critical to adapting responses against future waves of the pandemic. Most studies of NPIs thus far have relied on epidemiological data. Here, we report the impact of NPIs on the evolution of SARS-CoV-2, taking the perspective of the virus. We examined how variations through time and space of SARS-CoV-2 genomic divergence rates, which reflect variations of the epidemic reproduction number Rt, can be explained by NPIs and combinations thereof. Based on the analysis of 5,198 SARS-CoV-2 genomes from 57 countries along with a detailed chronology of 9 non-pharmaceutical interventions during the early epidemic phase up to May 2020, we find that home containment (35% Rt reduction) and education lockdown (26%) had the strongest predicted effectiveness. To estimate the cumulative effect of NPIs, we modelled the probability of reducing Rt below 1, which is required to stop the epidemic, for various intervention combinations and initial Rt values. In these models, no intervention implemented alone was sufficient to stop the epidemic for Rt’s above 2 and all interventions combined were required for Rt’s above 3. Our approach can help inform decisions on the minimal set of NPIs required to control the epidemic depending on the current Rt value.

scholarly journals State-level needs for social distancing and contact tracing to contain COVID-19 in the United States 

2020 ◽  
Author(s):  
Weihsueh A. Chiu ◽  
Rebecca Fischer ◽  
Martial L. Ndeffo-Mbah
Keyword(s):  
Large Scale ◽  
District Of Columbia ◽  
State Level ◽  
The United States ◽  
Contact Tracing ◽  
Social Distancing ◽  
Epidemic Curve ◽  
Dynamics And Control ◽  
And Control ◽  
The Impact

Abstract Starting in mid-May 2020, many US states began relaxing social distancing measures that were put in place to mitigate the spread of COVID-19. To evaluate the impact of relaxation of restrictions on COVID-19 dynamics and control, we developed a transmission dynamic model and calibrated it to US state-level COVID-19 cases and deaths. We used this model to evaluate the impact of social distancing, testing and contact tracing on the COVID-19 epidemic in each state. As of July 22, 2020, we found only three states were on track to curtail their epidemic curve. Thirty-nine states and the District of Columbia may have to double their testing and/or tracing rates and/or rolling back reopening by 25%, while eight states require an even greater measure of combined testing, tracing, and distancing. Increased testing and contact tracing capacity is paramount for mitigating the recent large-scale increases in U.S. cases and deaths.

scholarly journals The impact of school reopening on the spread of COVID-19 in England

2021 ◽  
Vol 376 (1829) ◽  
pp. 20200261
Author(s):  
Matt J. Keeling ◽  
Michael J. Tildesley ◽  
Benjamin D. Atkins ◽  
Bridget Penman ◽  
Emma Southall ◽  
...  
Keyword(s):  
Secondary Schools ◽  
Primary Schools ◽  
Reproduction Number ◽  
Health Impact ◽  
Transmission Model ◽  
Older Children ◽  
Developmental Needs ◽  
Social Distancing ◽  
The Uk ◽  
The Impact

By mid-May 2020, cases of COVID-19 in the UK had been declining for over a month; a multi-phase emergence from lockdown was planned, including a scheduled partial reopening of schools on 1 June 2020. Although evidence suggests that children generally display mild symptoms, the size of the school-age population means the total impact of reopening schools is unclear. Here, we present work from mid-May 2020 that focused on the imminent opening of schools and consider what these results imply for future policy. We compared eight strategies for reopening primary and secondary schools in England. Modifying a transmission model fitted to UK SARS-CoV-2 data, we assessed how reopening schools affects contact patterns, anticipated secondary infections and the relative change in the reproduction number, R . We determined the associated public health impact and its sensitivity to changes in social distancing within the wider community. We predicted that reopening schools with half-sized classes or focused on younger children was unlikely to push R above one. Older children generally have more social contacts, so reopening secondary schools results in more cases than reopening primary schools, while reopening both could have pushed R above one in some regions. Reductions in community social distancing were found to outweigh and exacerbate any impacts of reopening. In particular, opening schools when the reproduction number R is already above one generates the largest increase in cases. Our work indicates that while any school reopening will result in increased mixing and infection amongst children and the wider population, reopening schools alone in June 2020 was unlikely to push R above one. Ultimately, reopening decisions are a difficult trade-off between epidemiological consequences and the emotional, educational and developmental needs of children. Into the future, there are difficult questions about what controls can be instigated such that schools can remain open if cases increase. This article is part of the theme issue ‘Modelling that shaped the early COVID-19 pandemic response in the UK’.

scholarly journals SARS-CoV-2 transmission dynamics in Belarus in 2020 revealed by genomic and incidence data analysis

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Alina Nemira ◽  
Ayotomiwa Ezekiel Adeniyi ◽  
Elena L. Gasich ◽  
Kirill Y. Bulda ◽  
Leonid N. Valentovich ◽  
...  
Keyword(s):  
Large Scale ◽  
Reproduction Number ◽  
Developed Countries ◽  
Sociodemographic Factors ◽  
Genomic Diversity ◽  
Reproductive Number ◽  
Cumulative Number ◽  
Population Mobility ◽  
Genomic Epidemiology ◽  
The Impact

Abstract Background Non-pharmaceutical interventions (NPIs) have been implemented worldwide to curb COVID-19 spread. Belarus is a rare case of a country with a relatively modern healthcare system, where highly limited NPIs have been enacted. Thus, investigation of Belarusian COVID-19 dynamics is essential for the local and global assessment of the impact of NPI strategies. Methods We integrate genomic epidemiology and surveillance methods to investigate the spread of SARS-CoV-2 in Belarus in 2020. We utilize phylodynamics, phylogeography, and probabilistic bias inference to study the virus import and export routes, the dynamics of the effective reproduction number, and the incidence of SARS-CoV-2 infection. Results Here we show that the estimated cumulative number of infections by June 2020 exceeds the confirmed case number by a factor of ~4 (95% confidence interval (2; 9)). Intra-country SARS-CoV-2 genomic diversity originates from at least 18 introductions from different regions, with a high proportion of regional transmissions. Phylodynamic analysis indicates a moderate reduction of the effective reproductive number after the introduction of limited NPIs, but its magnitude is lower than for developed countries with large-scale NPIs. On the other hand, the effective reproduction number estimate is comparable with that for the neighboring Ukraine, where NPIs were broader. Conclusions The example of Belarus demonstrates how countries with relatively low outward population mobility continue to be integral parts of the global epidemiological environment. Comparison of the effective reproduction number dynamics for Belarus and other countries reveals the effect of different NPI strategies but also emphasizes the role of regional Eastern European sociodemographic factors in the virus spread.

scholarly journals Importance of untested infectious individuals for interventions to suppress COVID-19

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Francisco J. Pérez-Reche ◽  
Ken J. Forbes ◽  
Norval J. C. Strachan
Keyword(s):  
Hubei Province ◽  
Contact Tracing ◽  
Social Distancing ◽  
Early Stages ◽  
The Uk ◽  
The Impact

AbstractThe impact of the extent of testing infectious individuals on suppression of COVID-19 is illustrated from the early stages of outbreaks in Germany, the Hubei province of China, Italy, Spain and the UK. The predicted percentage of untested infected individuals depends on the specific outbreak but we found that they typically represent 60–80% of all infected individuals during the early stages of the outbreaks. We propose that reducing the underlying transmission from untested cases is crucial to suppress the virus. This can be achieved through enhanced testing in combination with social distancing and other interventions that reduce transmission such as wearing face masks. Once transmission from silent carriers is kept under control by these means, the virus could have been fully suppressed through fast isolation and contact tracing of tested cases.

scholarly journals State-level impact of social distancing and testing on COVID-19 in the United States

2020 ◽  
Author(s):  
Weihsueh A. Chiu ◽  
Rebecca Fischer ◽  
Martial L. Ndeffo-Mbah
Keyword(s):  
United States ◽  
Large Scale ◽  
Disease Incidence ◽  
State Level ◽  
The United States ◽  
Contact Tracing ◽  
Reproductive Number ◽  
Social Distancing ◽  
Epidemic Curve ◽  
The Impact

Abstract Social distancing measures have been implemented in the United States (US) since March 2020, to mitigate the spread of SARS-CoV-2, the causative agent of COVID-19. However, by mid-May most states began relaxing these measures to support the resumption of economic activity, even as disease incidence continued to increase in many states. To evaluate the impact of relaxing social distancing restrictions on COVID-19 dynamics and control in the US, we developed a transmission dynamic model and calibrated it to US state-level COVID-19 cases and deaths from March to June 20th, 2020, using Bayesian methods. We used this model to evaluate the impact of reopening, social distancing, testing, contact tracing, and case isolation on the COVID-19 epidemic in each state. We found that using stay-at-home orders, most states were able to curtail their COVID-19 epidemic curve by reducing and achieving an effective reproductive number below 1. But by June 20th, 2020, only 19 states and the District of Columbia were on track to curtail their epidemic curve with a 75% confidence, at current levels of reopening. Of the remaining 31 states, 24 may have to double their current testing and/or contact tracing rate to curtail their epidemic curve, and seven need to further restrict social contact by 25% in addition to doubling their testing and contact tracing rates. When social distancing restrictions are being eased, greater state-level testing and contact tracing capacity remains paramount for mitigating the risk of large-scale increases in cases and deaths.

scholarly journals SIREN protocol: Impact of detectable anti-SARS-CoV-2 on the subsequent incidence of COVID-19 in 100,000 healthcare workers: do antibody positive healthcare workers have less reinfection than antibody negative healthcare workers?

2020 ◽  
Author(s):  
S. Wallace ◽  
V. Hall ◽  
A. Charlett ◽  
P.D. Kirwan ◽  
M.J. Cole ◽  
...  
Keyword(s):  
Healthcare Workers ◽  
Large Scale ◽  
Antibody Test ◽  
Study Entry ◽  
Contact Tracing ◽  
Staff Members ◽  
Viral Culture ◽  
The Uk ◽  
Prospective Longitudinal ◽  
The Impact

AbstractBackgroundThe overall risk of reinfection in individuals who have previously had COVID-19 is unknown. To determine if prior SARS-CoV-2 infection (as determined by at least one positive commercial antibody test performed in a laboratory) in healthcare workers confers future immunity to reinfection, we are undertaking a large-scale prospective longitudinal cohort study of healthcare staff across the United Kingdom.MethodsPopulation and Setting: staff members of healthcare organisations working in hospitals in the UKAt recruitment, participants will have their serum tested for anti-SARS-CoV-2 at baseline and using these results will be initially allocated to either antibody positive or antibody negative cohorts. Participants will undergo antibody and viral RNA testing at 1-4 weekly intervals throughout the study period, and based on these results may move between cohorts. Any results from testing undertaken for other reasons (e.g. symptoms, contact tracing etc.) or prior to study entry will also be included. Individuals will complete enrolment and fortnightly questionnaires on exposures and symptoms. Follow-up will be for at least 12 months from study entry.OutcomeThe primary outcome of interest is a reinfection with SARS -CoV-2 during the study period. Secondary outcomes will include incidence and prevalence (both RNA and antibody) of SARS-CoV-2, viral genomics, viral culture, symptom history and antibody/neutralising antibody titres.ConclusionThis large study will help us to understand the impact of the presence of antibodies on the risk of reinfection with SARS-CoV-2; the results will have substantial implications in terms of national and international policy, as well as for risk management of contacts of COVID-19 cases.Trial RegistrationIRAS ID 284460, HRA and Health and Care Research Wales approval granted 22 May 2020.

scholarly journals Impact of relaxing Covid-19 social distancing measures on rural North Wales: a simulation analysis

2020 ◽  
Author(s):  
Rhodri P Hughes ◽  
Dyfrig A Hughes
Keyword(s):  
Simulation Analysis ◽  
Model Averaging ◽  
Incidence Rates ◽  
Cumulative Number ◽  
Social Distancing ◽  
Daily Data ◽  
North Wales ◽  
The Uk ◽  
Incident Cases ◽  
The Impact

Background: Social distancing policies aimed to limit Covid-19 are gradually being relaxed as nationally reported peaks in incident cases are passed. Population density is an important driver of national incidence rates; however peak incidences in rural regions may lag national figures by several weeks. We aimed to forecast the impact of relaxed social distancing rules on rural North Wales. Methods: Daily data on the deaths of people with a positive test for Covid-19 were obtained from Public Health Wales and the UK Government. Sigmoidal growth functions were fitted by non-linear least squares and model averaging used to extrapolate mortality over time. The dates of peak mortality incidences for North Wales, Wales and the UK; and the percentage predicted maximum mortality (as of 7th May 2020) were estimated. Results: The peak daily death rates in Wales and the UK were estimated to have occurred on the 14/04/2020 and 15/04/2020, respectively. For North Wales, this occurred on the 07/05/2020, corresponding to the date of analysis. The number of deaths reported in North Wales represents 31% of the predicted total cumulative number, compared with 71% and 60% for Wales and the UK, respectively. Conclusion: Policies governing the movement of people in the gradual release from lockdown are likely to impact significantly on areas −principally rural in nature− where cases of Covid-19, deaths and immunity are likely to be much lower than in populated areas. This is particularly difficult to manage across jurisdictions, such as between England and Wales, and in popular holiday destinations.

The field-scale evaluation of herbicide-tolerant genetically modified crops conducted in the UK (1998–2003)

10.5912/jcb77 ◽  
2004 ◽  
Vol 10 (3) ◽  
Author(s):  
Roger Turner
Keyword(s):  
Supply Chain ◽  
Large Scale ◽  
Genetically Modified ◽  
Genetically Modified Crops ◽  
Field Scale ◽  
Farmland Biodiversity ◽  
Herbicide Tolerant ◽  
Uk Government ◽  
The Uk ◽  
The Impact

In 1998 the UK Government, in conjunction with Supply Chain Initiative on Modified Agricultural Crops (SCIMAC, a cross-industry group representing the supply chain), established a large-scale programme to examine the impact of genetically modified herbicide-tolerant crops on farmland biodiversity. The trials programme lasted three years and was conducted by a consortium of scientists who were responsible to an independent scientific subcommittee. The background to the establishment of these trials is described and the political pressures facing the Government at that time and the reactions of key stakeholders are discussed.The field-scale evaluations were a pioneering project to examine the impact of genetically modified crops on farmland biodiversity. The exercise was one of the largest experiments ever carried out to measure the environmental impact of specific farming practices, and shows that robust results can be obtained, while the resultant database represents a wealth of ecological information on three important arable crops – beet, maize and oilseed rape. It is clear that other such trials could be carried out to test other variables as part of a longer-term effort to steer farm management systems in ways more acceptable to society. However, in view of their costs (both to the UK Government and the technology providers) together with the adverse response by the environmental campaign groups, and the length of time needed to carry out the work, it seems unlikely that an exercise of similar scale will be undertaken in the near future.

scholarly journals Modelling Capacity on London Underground Carriages in Light of UK Government Mandated Social Distancing Rules in Response to the Covid-19 Pandemic

2020 ◽  
Author(s):  
Justin Marley
Keyword(s):  
Carrying Capacity ◽  
Current Paper ◽  
Social Distancing ◽  
The Social ◽  
London Underground ◽  
Uk Government ◽  
The Uk ◽  
Transport For London ◽  
The Impact

ConsultantThe UK has been affected by the COVID-19 pandemic and London in particular has experienced a large number of cases. The London Underground is a key part of the transport for London. The UK Government has implemented social distancing rules meaning that people should be 2 metres from each other. The current paper models the impact of the social distancing on the carrying capacity of 10 different underground and overground carriages. The model determines the optimal standing and seating capacity for the different carriages and identifies logistical approaches to the seating and standing arrangements.

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