Abstract
With the rapid spread of the SARS-CoV-2 virus since Fall 2019, governments took various measures to contain the propagation of the pandemic, declared on March, 2020. This study introduces a novel method to estimate the reproductive number using Bayesian inference with time-dependent priors. By inferring the infection dates from incidence time series, the developed approach allows direct comparison between reproductive number and introduction of public health measures in a specific country. First a specific period between the onset of the symptoms and a case being declared as dead is derived on data available in Switzerland. Focussing on the measures taken by 31 European countries, this study shows that most countries required tough state interventions with a stringency index equal to 83.6 out of 100 to reduce the reproductive number below one and hence control the development of the epidemy. In addition, it is shown that there is a direct correlation between the time taken to introduce restrictive measures and the time required to contain the spread of the epidemy with a median time of 8 days between the introduction of initial restrictive measures and the reproductive rate reducing below one.
Competing Interest Statement
The authors have declared no competing interest.
Funding Statement
No external funding was received.
Author Declarations
I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.
Yes
The details of the IRB/oversight body that provided approval or exemption for the research described are given below:
N/A
All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.
Yes
I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).
Yes
I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.
Yes
Data Availability
The incidence data for the confirmed and death cases were recovered from:Johns Hopkins University Center for Systems Science and Engineering, COVID-19 data reposi-tory, Center for Systems Science and Engineering (CSSE): https://github.com/CSSEGISandData/COVID-19 [accessed on 23/05/2020]. Data regarding the state interventions were retrieved from: Thomas Hale, Sam Webster, Anna Peth-erick, Toby Phillips, and Beatriz Kira. (2020). Oxford COVID-19 Government Response Tracker,Blavatnik School of Government: https://github.com/OxCGRT/covid-policy-tracker [accessed on 23/05/2020]. The daily incidence for the death cases per million people was retrieved from: Max Roser, HannahRitchie, Esteban Ortiz-Ospina and Joe Hasell, Coronavirus Pandemic (COVID-19), Our World inData, https://ourworldindata.org/coronavirus [accessed on 24/05/2020] Data related to the period between a positive test and the death of an individual were retrieved from: Swiss Federal Office of Public Health (FOPH), Cas confirmes en laboratoire: distribution geographique, https://covid-19-schweiz.bagapps.ch/fr-1.html [accessed on 06/05/2020]