scholarly journals Non-pharmaceutical interventions and the emergence of pathogen variants

2021 ◽  
Author(s):  
Ben Ashby ◽  
Robin N Thompson
Keyword(s):  
Life History ◽  
Epidemiological Model ◽  
Contact Tracing ◽  
Pathogen Evolution ◽  
Social Distancing ◽  
Life History Characteristics ◽  
Novel Variants ◽  
Cross Immunity ◽  
Selection For ◽  
Pharmaceutical Interventions

Non-pharmaceutical interventions (NPIs), such as social distancing and contact tracing, have been widely implemented during the COVID-19 pandemic. In addition to playing an important role in suppressing transmission, NPIs influence pathogen evolution by mediating mutation supply and altering the strength of selection for novel variants. However, it is unclear how NPIs might affect the emergence of novel variants of concern that are able to escape pre-existing immunity (partially or fully), are more transmissible, or cause greater mortality. Here, we analyse a stochastic two-strain epidemiological model to determine how the strength of NPIs affects the emergence of variants with similar or contrasting life-history characteristics to the wildtype. We show that, while stronger and timelier NPIs generally reduce the likelihood of variant emergence, it is possible for more transmissible variants with high cross immunity to have a greater probability of emerging at intermediate levels of NPIs. However, since one cannot predict the characteristics of a variant, the best strategy to prevent emergence is likely to be implementation of strong, timely NPIs.

scholarly journals Estimating the effectiveness of non-pharmaceutical interventions on COVID-19 control in South Korea

2020 ◽  
Author(s):  
Kyung-Duk Min ◽  
Heewon Kang ◽  
Ju-Yeun Lee ◽  
Seonghee Jeon ◽  
Sung-il Cho
Keyword(s):  
South Korea ◽  
Compartment Model ◽  
Contact Tracing ◽  
Contact Rate ◽  
Global Public Health ◽  
Spring Semester ◽  
Detection Rates ◽  
Social Distancing ◽  
Effective Contact ◽  
Pharmaceutical Interventions

Abstract Background: The coronavirus disease 2019 (COVID-19) pandemic has posed significant global public health challenges and created a substantial economic burden. South Korea has experienced an extensive outbreak, which was linked to a religion-related super-spreading event. However, the implementation of various non-pharmaceutical interventions (NPIs), including social distancing, spring semester postponing, and extensive testing and contact tracing controlled the epidemic. Herein, we estimated the effectiveness of each NPI using a simulation model.Methods: A compartment model with a susceptible-exposed-infectious-quarantined-hospitalized (SEIQH) structure was employed. Using the Monte-Carlo-Markov-Chain algorithm with Gibbs’ sampling method, we estimated the time-varying effective contact rate to calibrate the model with the reported daily new confirmed cases from February 12th to March 31st (7 weeks). Moreover, we conducted scenario analyses by adjusting the parameters to estimate the effectiveness of NPI.Results: Relaxed social distancing among adults would have increased the number of cases 27-fold until the end of March, and the epidemic curve would have been similar to other high burden countries. Spring semester non-postponement would have increased the effective contact rate 2·4-fold among individuals aged 0-19, while lower quarantine and detection rates would have increased the number of cases 1·4-fold. Conclusions: Among the three NPI measures, social distancing in adults showed the highest effectiveness. The substantial effect of social distancing should be considered for developing an exit strategy.

scholarly journals Dynamical SPQEIR model assesses the effectiveness of non-pharmaceutical interventions against COVID-19 epidemic outbreaks

2020 ◽  
Author(s):  
Daniele Proverbio ◽  
Françoise Kemp ◽  
Stefano Magni ◽  
Andreas Husch ◽  
Atte Aalto ◽  
...  
Keyword(s):  
Decision Makers ◽  
Contact Tracing ◽  
Online Tool ◽  
Seir Model ◽  
Social Distancing ◽  
Quantitative Understanding ◽  
Cross Country ◽  
Pharmaceutical Interventions

AbstractAgainst the current COVID-19 pandemic, governments worldwide have devised a variety of non-pharmaceutical interventions to suppress it, but the efficacy of distinct measures is not yet well quantified. In this paper, we propose a novel tool to achieve this quantification. In fact, this paper develops a new extended epidemic SEIR model, informed by a socio-political classification of different interventions, to assess the value of several suppression approaches. First, we inquire the conceptual effect of suppression parameters on the infection curve. Then, we illustrate the potential of our model on data from a number of countries, to perform cross-country comparisons. This gives information on the best synergies of interventions to control epidemic outbreaks while minimising impact on socio-economic needs. For instance, our results suggest that, while rapid and strong lock-down is an effective pandemic suppression measure, a combination of social distancing and contact tracing can achieve similar suppression synergistically. This quantitative understanding will support the establishment of mid- and long-term interventions, to prepare containment strategies against further outbreaks. This paper also provides an online tool that allows researchers and decision makers to interactively simulate diverse scenarios with our model.

scholarly journals Non-pharmaceutical interventions for containment, mitigation and suppression of COVID-19 infection

2020 ◽  
pp. 1-25
Author(s):  
Daniel F. Patiño-Lugo ◽  
Marcela Velez ◽  
Pamela Velásquez Salazar ◽  
Claudia Yaneth Vera-Giraldo ◽  
Viviana Vélez ◽  
...  
Keyword(s):  
Health Care Services ◽  
Social Impact ◽  
Scientific Evidence ◽  
Policy Decision ◽  
Substantial Effect ◽  
Contact Tracing ◽  
Social Distancing ◽  
First Case ◽  
Travel Restrictions ◽  
Pharmaceutical Interventions

The best available scientific evidence is required to design effective non-pharmaceutical interventions (NPIs) to help policymakers to contain COVID-19 outbreaks. The aim of this review is to describe which NPIs used different countries and a when they use them. It also explores how NPIs impact the number of cases, the mortality, and the capacity of health systems. We consulted eight web pages of transnational organizations, 17 of international media, 99 of government institutions in the 19 countries included, and besides, we included nine studies (out of 34 identified) that met inclusion criteria. We found that some countries are focused on establishing travel restrictions, isolation of identified cases, and high-risk people. Others have a more intense combination of mandatory quarantine and other drastic social distancing measures. Some countries have implemented interventions in the first fifteen days after detecting the first case, while others have taken more than 30 days. The effectiveness of isolated NPIs may be limited, but combined interventions have shown to be effective in reducing the transmissibility of the disease, the collapse of health care services, and mortality. When the number of new cases has been controlled, it is necessary to maintain social distancing measures, self-isolation, and contact tracing for several months. The policy decision-making in this time should be aimed to optimize the opportunities of saving lives, reducing the collapse of health services, and minimizing the economic and social impact over the general population, but principally over the most vulnerable. The timing of implementing and lifting interventions is likely to have a substantial effect on those objectives.

scholarly journals Five approaches to the suppression of SARS-CoV-2 without intensive social distancing

2021 ◽  
Vol 288 (1949) ◽  
Author(s):  
John M. Drake ◽  
Kyle Dahlin ◽  
Pejman Rohani ◽  
Andreas Handel
Keyword(s):  
Narrow Range ◽  
Case Finding ◽  
Contact Tracing ◽  
Active Case Finding ◽  
Protective Measures ◽  
Social Distancing ◽  
Targeted Interventions ◽  
Wide Range ◽  
Alternative Approaches ◽  
Pharmaceutical Interventions

Initial efforts to mitigate transmission of SARS-CoV-2 relied on intensive social distancing measures such as school and workplace closures, shelter-in-place orders and prohibitions on the gathering of people. Other non-pharmaceutical interventions for suppressing transmission include active case finding, contact tracing, quarantine, immunity or health certification, and a wide range of personal protective measures. Here we investigate the potential effectiveness of these alternative approaches to suppression. We introduce a conceptual framework represented by two mathematical models that differ in strategy. We find both strategies may be effective, although both require extensive testing and work within a relatively narrow range of conditions. Generalized protective measures such as wearing face masks, improved hygiene and local reductions in density are found to significantly increase the effectiveness of targeted interventions.

scholarly journals A sub-national analysis of the rate of transmission of COVID-19 in Italy

2020 ◽  
Author(s):  
Michaela A. C. Vollmer ◽  
Swapnil Mishra ◽  
H Juliette T Unwin ◽  
Axel Gandy ◽  
Thomas A Mellan ◽  
...  
Keyword(s):  
Attack Rate ◽  
Herd Immunity ◽  
Transmission Intensity ◽  
Contact Tracing ◽  
Social Distancing ◽  
Italian Regions ◽  
Transmission Reduction ◽  
Using Data ◽  
National Analysis ◽  
Pharmaceutical Interventions

Italy was the first European country to experience sustained local transmission of COVID-19. As of 1st May 2020, the Italian health authorities reported 28,238 deaths nationally. To control the epidemic, the Italian government implemented a suite of non-pharmaceutical interventions (NPIs), including school and university closures, social distancing and full lockdown involving banning of public gatherings and non essential movement. In this report, we model the effect of NPIs on transmission using data on average mobility. We estimate that the average reproduction number (a measure of transmission intensity) is currently below one for all Italian regions, and significantly so for the majority of the regions. Despite the large number of deaths, the proportion of population that has been infected by SARS-CoV-2 (the attack rate) is far from the herd immunity threshold in all Italian regions, with the highest attack rate observed in Lombardy (13.18% [10.66%-16.70%]). Italy is set to relax the currently implemented NPIs from 4th May 2020. Given the control achieved by NPIs, we consider three scenarios for the next 8 weeks: a scenario in which mobility remains the same as during the lockdown, a scenario in which mobility returns to pre-lockdown levels by 20%, and a scenario in which mobility returns to pre-lockdown levels by 40%. The scenarios explored assume that mobility is scaled evenly across all dimensions, that behaviour stays the same as before NPIs were implemented, that no pharmaceutical interventions are introduced, and it does not include transmission reduction from contact tracing, testing and the isolation of confirmed or suspected cases. New interventions, such as enhanced testing and contact tracing are going to be introduced and will likely contribute to reductions in transmission; therefore our estimates should be viewed as pessimistic projections. We find that, in the absence of additional interventions, even a 20% return to pre-lockdown mobility could lead to a resurgence in the number of deaths far greater than experienced in the current wave in several regions. Future increases in the number of deaths will lag behind the increase in transmission intensity and so a second wave will not be immediately apparent from just monitoring of the daily number of deaths. Our results suggest that SARS-CoV-2 transmission as well as mobility should be closely monitored in the next weeks and months. To compensate for the increase in mobility that will occur due to the relaxation of the currently implemented NPIs, adherence to the recommended social distancing measures alongside enhanced community surveillance including swab testing, contact tracing and the early isolation of infections are of paramount importance to reduce the risk of resurgence in transmission.

scholarly journals Modelling the impact of household size distribution on the transmission dynamics of COVID-19

2021 ◽  
Author(s):  
Pengyu Liu ◽  
Lisa McQuarrie ◽  
Yexuan Song ◽  
Caroline Colijn
Keyword(s):  
British Columbia ◽  
Size Distribution ◽  
Household Size ◽  
Epidemiological Model ◽  
Transmission Dynamics ◽  
Social Distancing ◽  
Household Transmission ◽  
The Impact ◽  
Pharmaceutical Interventions ◽  
At Home

AbstractUnder the implementation of non-pharmaceutical interventions such as social distancing and lockdowns, household transmission has been shown to be significant for COVID-19, posing challenges for reducing incidence in settings where people are asked to self-isolate at home and to spend increasing amounts of time at home due to distancing measures. Accordingly, characteristics of households in a region have been shown to relate to transmission heterogeneity of the virus. We introduce a stochastic epidemiological model to examine the impact of the household size distribution in a region on the transmission dynamics. We choose parameters to reflect incidence in two health regions of the Greater Vancouver area in British Columbia and simulate the impact of distancing measures on transmission, with household size distribution the only different parameter between simulations for the two regions. Our result suggests that the dissimilarity in household size distribution alone can cause significant differences in incidence of the two regions, and the distributions drive distinct dynamics that match reported cases. Furthermore, our model suggests that offering individuals a place to isolate outside their household can speed the decline in cases, and does so more effectively where there are more larger households.

scholarly journals Five approaches to the suppression of SARS-CoV-2 without intensive social distancing

2020 ◽  
Author(s):  
John Drake ◽  
Pejman Rohani ◽  
Kyle Dahlin ◽  
Andreas Handel
Keyword(s):  
Narrow Range ◽  
Case Finding ◽  
Contact Tracing ◽  
Active Case Finding ◽  
Protective Measures ◽  
Social Distancing ◽  
Targeted Interventions ◽  
Wide Range ◽  
Alternative Approaches ◽  
Pharmaceutical Interventions

Initial efforts to mitigate transmission of SARS-CoV-2 relied on intensive social distancing measures such as school and workplace closures, shelter-in-place orders, and prohibitions on the gathering of people. Other non-pharmaceutical interventions for suppressing transmission include active case finding, contact tracing, quarantine, immunity or health certification, and a wide range of personal protective measures. Here we investigate the potential effectiveness of these alternative approaches to suppression. We introduce a conceptual framework represented by two mathematical models that differ in strategy. We find both strategies may be effective, although both require extensive testing and work within a relatively narrow range of conditions. Generalized protective measures such as wearing face masks, improved hygiene, and local reductions in density are found to significantly increase the effectiveness of targeted interventions.

Are social networking platforms the key to effective social distancing for COVID-19? (Preprint)

2020 ◽  
Author(s):  
Viknesh Sounderajah ◽  
Hutan Ashrafian ◽  
Sheraz Markar ◽  
Ara Darzi
Keyword(s):  
Operating System ◽  
Social Networking ◽  
Contact Tracing ◽  
Text Data ◽  
Social Distancing ◽  
Web Mapping ◽  
Viral Spread ◽  
Behavioural Insights ◽  
Mapping Software ◽  
Incidence And Mortality

UNSTRUCTURED If health systems are to effectively employ social distancing measures to in response to further COVID-19 peaks, they must adopt new behavioural metrics that can supplement traditional downstream measures, such as incidence and mortality. Access to mobile digital innovations may dynamically quantify compliance to social distancing (e.g. web mapping software) as well as establish personalised real-time contact tracing of viral spread (e.g. mobile operating system infrastructure through Google-Apple partnership). In particular, text data from social networking platforms can be mined for unique behavioural insights, such as symptom tracking and perception monitoring. Platforms, such as Twitter, have shown significant promise in tracking communicable pandemics. As such, it is critical that social networking companies collaborate with each other in order to (1) enrich the data that is available for analysis, (2) promote the creation of open access datasets for researchers and (3) cultivate relationships with governments in order to affect positive change.

scholarly journals Dataset on SARS-CoV-2 non-pharmaceutical interventions in Brazilian municipalities

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Andreza Aruska de Souza Santos ◽  
Darlan da Silva Candido ◽  
William Marciel de Souza ◽  
Lewis Buss ◽  
Sabrina L. Li ◽  
...  
Keyword(s):  
Local Governments ◽  
Federal District ◽  
Social Distancing ◽  
Survey Responses ◽  
Municipal Level ◽  
Pharmaceutical Interventions

AbstractBrazil has one of the fastest-growing COVID-19 epidemics worldwide. Non-pharmaceutical interventions (NPIs) have been adopted at the municipal level with asynchronous actions taken across 5,568 municipalities and the Federal District. This paper systematises the fragmented information on NPIs reporting on a novel dataset with survey responses from 4,027 mayors, covering 72.3% of all municipalities in the country. This dataset responds to the urgency to track and share findings on fragmented policies during the COVID-19 pandemic. Quantifying NPIs can help to assess the role of interventions in reducing transmission. We offer spatial and temporal details for a range of measures aimed at implementing social distancing and the dates when these measures were relaxed by local governments.

scholarly journals COVID-19 Pandemic Response Simulation in a Large City: Impact of Nonpharmaceutical Interventions on Reopening Society

2021 ◽  
pp. 0272989X2110030
Author(s):  
Serin Lee ◽  
Zelda B. Zabinsky ◽  
Judith N. Wasserheit ◽  
Stephen M. Kofsky ◽  
Shan Liu
Keyword(s):  
Large City ◽  
Face Mask ◽  
School Closure ◽  
Contact Tracing ◽  
The Novel ◽  
Agent Based ◽  
Social Distancing ◽  
Variable Compliance ◽  
Novel Coronavirus ◽  
Nonpharmaceutical Interventions

As the novel coronavirus (COVID-19) pandemic continues to expand, policymakers are striving to balance the combinations of nonpharmaceutical interventions (NPIs) to keep people safe and minimize social disruptions. We developed and calibrated an agent-based simulation to model COVID-19 outbreaks in the greater Seattle area. The model simulated NPIs, including social distancing, face mask use, school closure, testing, and contact tracing with variable compliance and effectiveness to identify optimal NPI combinations that can control the spread of the virus in a large urban area. Results highlight the importance of at least 75% face mask use to relax social distancing and school closure measures while keeping infections low. It is important to relax NPIs cautiously during vaccine rollout in 2021.

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