Covid-19 Transmission Trajectories–Monitoring the Pandemic in the Worldwide Context

Abstract

The Covid-19 pandemic is developing worldwide with common dynamics but also with marked differences between regions and countries. These are not completely understood, but presumably, provide a clue to find ways to mitigate epidemics until strategies leading to its eradication become available. We describe an iteractive monitoring tool available in the internet. It enables inspection of the dynamic state of the epidemic in 187 countries using trajectories that visualize the transmission and removal rates of the epidemic and in this way bridge epi-curve tracking with modelling approaches. Examples were provided which characterize state of epidemic in different regions of the world in terms of fast and slow growing and decaying regimes and estimate associated rate factors. The basic spread of the disease is associated with transmission between two individuals every two-three days on the average. Non-pharmaceutical interventions decrease this value to up to ten days, whereas ‘complete lock down’ measures are required to stop the epidemic. Comparison of trajectories revealed marked differences between the countries regarding efficiency of measures taken against the epidemic. Trajectories also reveal marked country-specific recovery and death rate dynamics. The results presented refer to the pandemic state in May to July 2020 and can serve as ‘working instruction’ for timely monitoring using the interactive monitoring tool as a sort of ‘seismometer’ for the evaluation of the state of epidemic, e.g., the possible effect of measures taken in both, lock-down and lock-up directions. Comparison of trajectories between countries and regions will support developing hypotheses and models to better understand regional differences of dynamics of Covid-19.

Non-pharmaceutical interventions during the COVID-19 pandemic: A review

“…The list does not come as surprise considering the epicenter of the pandemic, data availability as well as the evolution of the pandemic in USA and Europe. However, few models in the sample consider hundreds of countries [22] , [44] , [45] , [45] , [46] , [47] . Second, this body of research has been published by authors with affiliations in countries.…”

“…The first column describes the main categories, the second the sub-categories, the last the country/countries focus of each study and the references. Category Subcategory Country/countries of study and reference Compartmental SIR-like Brazil, China [48] ; China [49] , [50] , [51] ; China, Italy [52] ; China, France, Iran, Italy, South Korea, USA [53] ; France, Iran, Italy [54] ; Germany [55] ; India [56] ; Italy [57] ; USA [58] ; 187 countries [45] ; several European countries [44] , [59] SIR-like age structured China [60] , Italy [61] , 143 countries [47] SEIR-like Argentina, Japan, Indonesia, New Zealand, Spain, USA [62] ; Canada [63] , [64] ; Canada, Germany, Italy [65] ; China [66] , [67] , [68] , [69] ; China, Italy [70] ; China, UK [71] ; Germany [72] ; India [73] , [74] ; Indonesia [75] ; Ireland [76] ; Mexico [77] ; Pakistan [78] ; South Korea [79] , [80] ; Switzerland [81] ; USA [82] , [83] ...…”

“…We start considering the body of modeling work based on SIR-like models. This subset of papers studies the effects of isolation and quarantine policies [49] , models NPIs as effective changes of the parameters [44] , [45] , [48] , [50] , [52] , [54] , [55] , [56] , [57] , [59] , investigates the impact of different policies [53] , [58] , and defines the conditions for the optimal control of the spreading [51] . In the following, I will highlight some of these approaches.…”

“…Ref. [45] adopts an extension of the SIR archetype, considering time-varying recovery and infection rates, to model the spreading of COVID-19 in countries. The results, that can be explored via an interactive tool, 5 are obtained fitting the parameters to the real epidemic data.…”

Web tools to fight pandemics: the COVID-19 experience

“…A similar concept can be found in the Harvard COVID-19 Simulator, an interactive Shiny web tool to inform COVID-19 intervention policy decisions in the USA, and CovidSIM, which applies a SEIR simulation model to estimate the potential health impact of the COVID-19 pandemic on a hypothetical European country [ 27 ]. COVID-19 trajectory viewer is another similar tool to monitor cases over time and predict trajectories in the future [ 28 ]. The common meaning of trajectory tools is to evaluate how different countries are responding to the disease spreading in order to ‘flatten the curve’ i.e.…”