scholarly journals Estimates of the ongoing need for social distancing and control measures post-“lockdown” from trajectories of COVID-19 cases and mortality

2020 ◽  
Vol 56 (1) ◽  
pp. 2001483 ◽  
Author(s):  
Mike Lonergan ◽  
James D. Chalmers
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Economic Activity ◽  
Regression Models ◽  
Reproduction Number ◽  
Viral Transmission ◽  
Control Measures ◽  
Social Distancing ◽  
And Control ◽  
Doubling Times

By 21 May 2020, severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) had caused more than 5 million cases of coronavirus 2019 (COVID-19) across more than 200 countries. Most countries with significant outbreaks have introduced social distancing or “lockdown” measures to reduce viral transmission. So the key question now is when, how and to what extent these measures can be lifted.Publicly available data on daily numbers of newly confirmed cases and mortality were used to fit regression models estimating trajectories, doubling times and the reproduction number (R0) of the disease, before and under the control measures. These data ran up to 21 May 2020, and were sufficient for analysis in 89 countries.The estimates of R0 before lockdown based on these data were broadly consistent with those previously published: between 2.0 and 3.7 in the countries with the largest number of cases available for analysis (USA, Italy, Spain, France and UK). There was little evidence to suggest that the restrictions had reduced R far below 1 in many places, with France having the most rapid reductions: R0 0.76 (95% CI 0.72–0.82) based on cases, and 0.77 (95% CI 0.73–0.80) based on mortality.Intermittent lockdown has been proposed as a means of controlling the outbreak while allowing periods of increased freedom and economic activity. These data suggest that few countries could have even 1 week per month unrestricted without seeing resurgence of the epidemic. Similarly, restoring 20% of the activity that has been prevented by the lockdowns looks difficult to reconcile with preventing the resurgence of the disease in most countries.

scholarly journals Estimates of the ongoing need for social distancing and control measures post-“lockdown” from trajectories of COVID-19 cases and mortality

2020 ◽  
Author(s):  
Mike Lonergan ◽  
James Chalmers
Keyword(s):  
Economic Activity ◽  
Regression Models ◽  
Reproduction Number ◽  
Viral Transmission ◽  
Control Measures ◽  
Sufficient Data ◽  
Social Distancing ◽  
And Control ◽  
Doubling Times

AbstractBy 29th April 2020, COVID-19 had caused more than 3 million cases across more than 200 countries. And most countries with significant outbreaks had introduced social distancing or “lockdown” measures to reduce viral transmission. So the key question now is when, how, and to what extent, these measures can be lifted.By fitting regression models to publically available data on daily numbers of newly-confirmed cases and mortality, trajectories, doubling times and reproduction number (R0) were estimated both before and under the control measures. These data ran up to 29th April 2020, and covered 73 countries that had provided sufficient data for modelling.The estimates of R0, before lockdown, based on these data were broadly consistent with those previously published at between 2.0 and 3.7 in the countries with the largest number of cases available for analysis (USA, Italy, Spain, France and UK). There was little evidence to suggest that the restrictions had reduced R far below 1 in many places, with France having the most rapid reductions – R0 0.77 (95%CI 0.68-0.87), based on cases and 0.78 (95%CI 0.68-0.88) based on mortality.Intermittent lockdown has been proposed as a means of controlling the outbreak while allowing periods of increase freedom and economic activity. These data suggest that few countries could have even one week per month unrestricted without seeing resurgence of the epidemic. Similarly, restoring 20% of the activity that has been prevented by the lockdowns looks difficult to reconcile with preventing the resurgence of the disease in most countries.

scholarly journals 365 days with COVID-19 in Iran: data analysis and epidemic curves

2021 ◽  
Author(s):  
Ebrahim Sahafizadeh ◽  
Saeed Talatian Azad
Keyword(s):  
Death Rate ◽  
Reproduction Number ◽  
Pearson Correlation ◽  
Control Measures ◽  
Social Distancing ◽  
The Government ◽  
Prevention And Control Measures ◽  
Reported Data ◽  
And Control ◽  
The Impact

AbstractBackgroundThe first confirmed cases of COVID-19 in Iran were reported on February 19, 2020. This study aimed to analyze the epidemic curves and to investigate the correlation between epidemic parameters and furthermore to analyze the impact of control measures on the spread of COVID-19 in Iran during 365 days of the epidemic.MethodsWe used data from February 20, 2020, to February 18, 2021, on the number of COVID-19 cases reported by Iranian governments. Pearson correlation coefficient was applied to investigate the correlation between different epidemic parameters. The number of daily deaths per daily new cases was averaged to calculate daily death rate and the same method was used to investigate the rate of daily positive tests. Furthermore, we employed two different methods to calculate the effective reproduction number using reported data.ResultsThe results showed that there was a strong correlation between the number of daily deaths and the number of daily new cases (specially the admitted cases). The results also indicated that the mean of daily death rate of COVID-19 during 365 days was 4.9 percent, and averagely 13.9 percent of daily tests results were positive. Furthermore, epidemic curves showed that implementing strict social distancing measures effectively reduced the number of confirmed cases. The effective reproduction curve indicated that social distancing is still necessary to control the spread of COVID-19 in Iran.ConclusionsAnalyzing the prevention and control measures indicated that the strict social distancing implemented by the government effectively reduces the number of new cases and deaths. The curve of reproduction number also showed that effective reproduction number is still above one; hence, it is necessary to continue strict social distancing and control travelling to prevent causing another wave of outbreak especially in Persian New Year.

scholarly journals Analysis and prediction of the coronavirus disease epidemic in China based on an individual-based model

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Zuiyuan Guo ◽  
Dan Xiao
Keyword(s):  
Reproduction Number ◽  
Control Measures ◽  
Cumulative Number ◽  
Individual Based Model ◽  
Whole Process ◽  
Coordinate Descent Algorithm ◽  
Initial Stage ◽  
The Government ◽  
Prevention And Control Measures ◽  
And Control

AbstractWe established a stochastic individual-based model and simulated the whole process of occurrence, development, and control of the coronavirus disease epidemic and the infectors and patients leaving Hubei Province before the traffic was closed in China. Additionally, the basic reproduction number (R0) and number of infectors and patients who left Hubei were estimated using the coordinate descent algorithm. The median R0 at the initial stage of the epidemic was 4.97 (95% confidence interval [CI] 4.82–5.17). Before the traffic lockdown was implemented in Hubei, 2000 (95% CI 1982–2030) infectors and patients had left Hubei and traveled throughout the country. The model estimated that if the government had taken prevention and control measures 1 day later, the cumulative number of laboratory-confirmed patients in the whole country would have increased by 32.1%. If the lockdown of Hubei was imposed 1 day in advance, the cumulative number of laboratory-confirmed patients in other provinces would have decreased by 7.7%. The stochastic model could fit the officially issued data well and simulate the evolution process of the epidemic. The intervention measurements nationwide have effectively curbed the human-to-human transmission of severe acute respiratory syndrome coronavirus 2.

scholarly journals Heterogeneity and effectiveness analysis of COVID-19 prevention and control in major cities in China through time-varying reproduction number estimation

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Qing Cheng ◽  
Zeyi Liu ◽  
Guangquan Cheng ◽  
Jincai Huang
Keyword(s):  
Prevention And Control ◽  
Large Scale ◽  
Reproduction Number ◽  
Correlation Method ◽  
Control Measures ◽  
Time Varying ◽  
Short Period ◽  
Significant Difference ◽  
Prevention And Control Measures ◽  
And Control

AbstractBeginning on December 31, 2019, the large-scale novel coronavirus disease 2019 (COVID-19) emerged in China. Tracking and analysing the heterogeneity and effectiveness of cities’ prevention and control of the COVID-19 epidemic is essential to design and adjust epidemic prevention and control measures. The number of newly confirmed cases in 25 of China’s most-affected cities for the COVID-19 epidemic from January 11 to February 10 was collected. The heterogeneity and effectiveness of these 25 cities’ prevention and control measures for COVID-19 were analysed by using an estimated time-varying reproduction number method and a serial correlation method. The results showed that the effective reproduction number (R) in 25 cities showed a downward trend overall, but there was a significant difference in the R change trends among cities, indicating that there was heterogeneity in the spread and control of COVID-19 in cities. Moreover, the COVID-19 control in 21 of 25 cities was effective, and the risk of infection decreased because their R had dropped below 1 by February 10, 2020. In contrast, the cities of Wuhan, Tianmen, Ezhou and Enshi still had difficulty effectively controlling the COVID-19 epidemic in a short period of time because their R was greater than 1.

scholarly journals COVID-19 in South Korea: Proper timing for Easing Mask mandates after COVID-19 Vaccination

2021 ◽  
pp. 1-9
Author(s):  
Yun-Jung Kang
Keyword(s):  
South Korea ◽  
Disease Control ◽  
Prevention And Control ◽  
Control Measures ◽  
Social Distancing ◽  
Proper Timing ◽  
Control And Prevention ◽  
Prevention And Control Measures ◽  
And Control

Abstract As of 25 July 2021, the Korea Disease Control and Prevention Agency reported 1,422 new COVID-19 cases, 188,848 total cases, and 2.073 total deaths (1.10% fatality rates). Since the first SARS-CoV-2 case was reported, efforts to find a treatment and vaccine against COVID-19 have been widespread. Four vaccines are on the WHO’s emergency use listing and are approved of their usage; BNT162b2, mRNA-1273, AZD1222, and Ad26.COV2.S. Vaccines against SARS-CoV-2 need at least 14 days to achieve effectiveness. Thus, people should abide by prevention and control measures, including wearing masks, washing hands, and social distancing. However, a lot of new cases were reported after vaccinations, as many people did not follow the prevention control measures before the end of the 14 days period. There is no doubt we need to break free from mask mandates. But let us not decide the timing in haste. Even if the mask mandates are eased, they should be changed depending on the number of reported cases, vaccinations, as well as prevention and control measures on how circumstances are changing under the influence of mutant coronavirus.

scholarly journals Estimated transmissibility and impact of SARS-CoV-2 lineage B.1.1.7 in England

Science ◽  
2021 ◽  
Vol 372 (6538) ◽  
pp. eabg3055 ◽  
Author(s):  
Nicholas G. Davies ◽  
Sam Abbott ◽  
Rosanna C. Barnard ◽  
Christopher I. Jarvis ◽  
Adam J. Kucharski ◽  
...  
Keyword(s):  
United States ◽  
Severe Acute Respiratory Syndrome ◽  
Reproduction Number ◽  
The United States ◽  
Control Measures ◽  
Transmission Model ◽  
Educational Institutions ◽  
Stringent Control ◽  
Dynamic Transmission Model ◽  
Credible Intervals

A severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant, VOC 202012/01 (lineage B.1.1.7), emerged in southeast England in September 2020 and is rapidly spreading toward fixation. Using a variety of statistical and dynamic modeling approaches, we estimate that this variant has a 43 to 90% (range of 95% credible intervals, 38 to 130%) higher reproduction number than preexisting variants. A fitted two-strain dynamic transmission model shows that VOC 202012/01 will lead to large resurgences of COVID-19 cases. Without stringent control measures, including limited closure of educational institutions and a greatly accelerated vaccine rollout, COVID-19 hospitalizations and deaths across England in the first 6 months of 2021 were projected to exceed those in 2020. VOC 202012/01 has spread globally and exhibits a similar transmission increase (59 to 74%) in Denmark, Switzerland, and the United States.

scholarly journals Delaying the COVID-19 epidemic in Australia: Evaluating the effectiveness of international travel bans

2020 ◽  
Author(s):  
Adeshina I. Adekunle ◽  
Michael Meehan ◽  
Dianna Rojas ◽  
James Trauer ◽  
Emma McBryde
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
International Travel ◽  
Control Measures ◽  
Social Distancing ◽  
Novel Virus

AbstractFollowing the outbreak of novel Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) or COVID-19 in Wuhan, China late 2019, different countries have put in place interventions such as travel ban, proper hygiene, and social distancing to slow the spread of this novel virus. We evaluated the effects of travel bans in the Australia context and projected the epidemic until May 2020. Our modelling results closely align with observed cases in Australia indicating the need for maintaining or improving on the control measures to slow down the virus.

scholarly journals The Saudi Infection Control Guidance for Re-opening Dental Services in Governmental and Private Sectors During Coronavirus Disease-2019 Pandemic

2021 ◽  
Vol 15 (1) ◽  
pp. 64-70
Author(s):  
Ali AlAhdal ◽  
Haila Al-Huraishi ◽  
Ahmad Almalag ◽  
Adel Alrusayes ◽  
Saud M Orfali
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Infection Control ◽  
Prevention And Control ◽  
Infection Prevention ◽  
Dental Treatment ◽  
Dental Health ◽  
Control Measures ◽  
Infection Prevention And Control ◽  
Dental Services ◽  
And Control

Objective: Novel newly discovered coronavirus, also known as severe acute respiratory syndrome coronavirus-2, is a recently emerging virus that has been rapidly spreading globally since December 2019. Due to the vicinity inoro-dental treatment and aerosol production, people inside the dental office are at high risk of being infected with severe acute respiratory syndrome coronavirus-2. This guideline aims to protect the dental health-care workers during their plans to re-open and increasingly continue their routine services until further notice from their governing body. Methods: A panel of experts in dentistry and infection prevention and control reviewed the local and global research and guidelines related to infection prevention and control during coronavirus disease-2019, along with the re-opening guidance provided by different entities. Results: Such a document might either be adopted or adapted to any regional and international organization that wishes to use a revised professional guideline in infection prevention and control dental services. Conclusion: A careful re-opening plan should be developed and implemented, including strict infection control measures before resuming the dental practice.

scholarly journals Sustainable social distancing through facemask use and testing during the Covid-19 pandemic

2020 ◽  
Author(s):  
Diego Chowell ◽  
Kimberlyn Roosa ◽  
Ranu Dhillon ◽  
Gerardo Chowell ◽  
Devabhaktuni Srikrishna
Keyword(s):  
Basic Reproduction Number ◽  
Symptom Onset ◽  
Social Protection ◽  
Reproduction Number ◽  
Type Model ◽  
Protective Behaviors ◽  
Social Distancing ◽  
And Control ◽  
Different Levels ◽  
The Basic Reproduction Number

We investigate how individual protective behaviors, different levels of testing, and isolation influence the transmission and control of the COVID-19 pandemic. Based on an SEIR-type model incorporating asymptomatic but infectious individuals (40%), we show that the pandemic may be readily controllable through a combination of testing, treatment if necessary, and self-isolation after testing positive (TTI) of symptomatic individuals together with social protection (e.g., facemask use, handwashing). When the basic reproduction number, R0, is 2.4, 65% effective social protection alone (35% of the unprotected transmission) brings the R below 1. Alternatively, 20% effective social protection brings the reproduction number below 1.0 so long as 75% of the symptomatic population is covered by TTI within 12 hours of symptom onset. Even with 20% effective social protection, TTI of 1 in 4 symptomatic individuals can substantially 'flatten the curve' cutting the peak daily incidence in half.

scholarly journals Whole-genome Sequencing to Track Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Transmission in Nosocomial Outbreaks

2020 ◽  
Author(s):  
Mary Lucey ◽  
Guerrino Macori ◽  
Niamh Mullane ◽  
Una Sutton-Fitzpatrick ◽  
Gabriel Gonzalez ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Genome Sequencing ◽  
Close Contact ◽  
Clinical Care ◽  
Virus Genome ◽  
Control Measures ◽  
Infection Prevention And Control ◽  
Route Of Transmission ◽  
Hospital Acquired ◽  
And Control

Abstract Background During the first wave of the coronavirus disease 2019 (COVID-19) pandemic, outbreaks of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in healthcare institutions posed a significant problem. Due to limited evidence, guidance on appropriate infection prevention and control (IPC) measures such as the wearing of face masks varied. Here, we applied whole virus genome sequencing (WvGS) to analyze transmission routes of SARS-CoV-2 in hospital-acquired (HA) COVID-19. Methods An investigation was undertaken for all HA cases of COVID-19 from March to April 2020. Fifty SARS-CoV-2 samples were analysed by WvGS and their phylogenetic relationship established. Results WvGS identified transmission events previously undetected by epidemiological analysis and provided evidence for SARS-CoV-2 transmission between healthcare workers (HCW) and patients and among HCW themselves. The majority of HA COVID-19 cases occurred in patients highly dependent on nursing care, suggesting the likely route of transmission was by close contact or droplet, rather than aerosol, transmission. Mortality among HA COVID-19 infections was recorded as 33%. Conclusions This study provides evidence that SARS-CoV-2 transmission occurs from symptomatic and asymptomatic HCWs to patients. Interventions including comprehensive screening of HCWs for COVID-19 symptoms, PCR testing of asymptomatic HCWs upon identification of HA cases and implementation of universal use of surgical masks for all clinical care is indicated to prevent viral transmission. Our study highlights the importance of close collaboration between guidance bodies and frontline IPC experts for developing control measures in an emergency pandemic situation caused by a virus with undefined transmission modus.

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