scholarly journals Analysis of Potential Risk of COVID-19 Infections in China Based on a Pairwise Epidemic Model

2020 ◽  
Author(s):  
Xiaofeng Luo ◽  
Shanshan Feng ◽  
Junyuan Yang ◽  
Xiao-Long Peng ◽  
Xiaochun Cao ◽  
...  
Keyword(s):  
Epidemic Model ◽  
Reproduction Number ◽  
Economic Benefits ◽  
Control Measures ◽  
Contact Tracing ◽  
The Novel ◽  
The Public ◽  
Disease Propagation ◽  
Long Run ◽  
Novel Coronavirus

The ongoing outbreak of the novel coronavirus pneumonia (also known as COVID-19) has triggered a series of stringent control measures in China, such as city closure, traffic restrictions, contact tracing and household quarantine. These containment efforts often lead to changes in the contact pattern among individuals of the population. Many existing compartmental epidemic models fail to account for the effects of contact structure. In this paper, we devised a pairwise epidemic model to analyze the COVID-19 outbreak in China based on confirmed cases reported during the period February 3rd--17th, 2020. By explicitly incorporating the effects of family clusters and contact tracing followed by household quarantine and isolation, our model provides a good fit to the trajectory of COVID-19 infections and is useful to predict the epidemic trend. We obtained the average of the reproduction number $R=1.494$ ($95\%$ CI: $1.483-1.507$) for Hubei province and $R=1.178$ ($95\%$ CI: $1.145-1.158$) for China (except Hubei), suggesting that some existing studies may have overestimated the reproduction number by neglecting the dynamical correlations and clustering effects. We forecasted that the COVID-19 epidemic would peak on February 13th ($95\%$ CI: February $9-17$th) in Hubei and 6 days eariler in the regions outside Hubei. Moreover the epidemic was expected to last until the middle of March in China (except Hubei) and late April in Hubei. The sensitivity analysis shows that ongoing exposure for the susceptible and population clustering play an important role in the disease propagation. With the enforcement of household quarantine measures, the reproduction number $R$ effectively reduces and epidemic quantities decrease accordingly. Furthermore, we gave an answer to the public concern on how long the stringent containment strategies should maintain. Through numerical analysis, we suggested that the time for the resumption of work and production in China (except Hubei) and Hubei would be the middle of March and the end of April, 2020, respectively. These constructive suggestions may bring some immeasurable social-economic benefits in the long run.

Coronavirus: Towards controlling of the pandemic - Indian scenario

2020 ◽  
Vol 11 (SPL1) ◽  
pp. 462-468
Author(s):  
Latika kothari ◽  
Sanskruti Wadatkar ◽  
Roshni Taori ◽  
Pavan Bajaj ◽  
Diksha Agrawal
Keyword(s):  
Control Measures ◽  
The Novel ◽  
Medical Treatments ◽  
Health Crisis ◽  
The Public ◽  
Infection Control Measures ◽  
The Social ◽  
Asking Questions ◽  
The Government ◽  
Novel Coronavirus

Coronavirus disease 2019 (COVID-19) is a communicable infection caused by the novel coronavirus resulting in severe acute respiratory syndrome coronavirus 2 (SARS-CoV). It was recognized to be a health crisis for the general population of international concern on 30th January 2020 and conceded as a pandemic on 11th March 2020. India is taking various measures to fight this invisible enemy by adopting different strategies and policies. To stop the COVID-19 from spreading, the Home Affairs Ministry and the health ministry, of India, has issued the nCoV 19 guidelines on travel. Screening for COVID-19 by asking questions about any symptoms, recent travel history, and exposure. India has been trying to get testing kits available. The government of India has enforced various laws like the social distancing, Janata curfew, strict lockdowns, screening door to door to control the spread of novel coronavirus. In this pandemic, innovative medical treatments are being explored, and a proper vaccine is being hunted to deal with the situation. Infection control measures are necessary to prevent the virus from further spreading and to help control the current situation. Thus, this review illustrates and explains the criteria provided by the government of India to the awareness of the public to prevent the spread of COVID-19.

scholarly journals Mathematical modelling of COVID-19 transmission and control strategies in the population of Bauchi State, Nigeria

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Yusuf Abdu Misau ◽  
Nanshin Nansak ◽  
Aliyu Maigoro ◽  
Sani Malami ◽  
Dominic Mogere ◽  
...  
Keyword(s):  
Reproduction Number ◽  
Control Strategies ◽  
Research Work ◽  
Control Measures ◽  
High Rate ◽  
World Health ◽  
Contact Tracing ◽  
Model Parameters ◽  
Deterministic System ◽  
The Novel

The novel SARS-COV-2 has since been declared a pandemic by the World Health Organization (WHO). The virus has spread from Wuhan city in China in December 2019 to no fewer than 200 countries as at June 2020 and still counting. Nigeria is currently experiencing a rapid spread of the virus amidst weak health system and more than 80% of population leaving on less than 1USD per day. To help understand the behavior of the virus in resource limited settings, we modelled the outbreak of COVID-19 and effects of control strategies in Bauchi state at north-eastern Nigeria. Using the real data of Bauchi state COVID-19 project, this research work extends the epidemic SEIR model by introducing new parameters based on the transmission dynamics of the novel COVID-19 pandemic and preventive measures. The total population of Bauchi State at the time of the study, given by is compartmentalized into five (5) different compartments as follows: Susceptible (S), Exposed (E), Infectious (I), Quarantined (Q) and Recovered (R). The new model is SEIQR. N = S → E → I → Q → R Data was collected by accessing Bauchi state electronic database of COVID-19 project to derive all the model parameters, while analysis and model building was done using Maple software. At the time of this study, it was found that the reproduction number R, for COVID-19 in Bauchi state, is 2.6 × 10-5. The reproduction number R decreased due to the application of control measures. The compartmental SEIRQ model in this study, which is a deterministic system of linear differential equations, has a continuum of disease-free equilibria, which is rigorously shown to be locallyasymptotically stable as the epidemiological threshold, known as the control reproduction number R= 0.0000026 is less than unity. The implication of this study is that the COVID-19 pandemic can be effectively controlled in Bauchi, since is R<1. Contact tracing and isolation must be increased as the models shows, the rise in infected class is a sign of high vulnerability of the population. Unless control measures are stepped up, despite high rate of recovery as shown by this study, infection rate will keep increasing as currently there is a no vaccine for COVID-19.

scholarly journals Time from Symptom Onset to Hospitalisation of Coronavirus Disease 2019 (COVID-19) Cases: Implications for the Proportion of Transmissions from Infectors with Few Symptoms

2020 ◽  
Vol 9 (5) ◽  
pp. 1297 ◽  
Author(s):  
Robin N. Thompson ◽  
Francesca A. Lovell-Read ◽  
Uri Obolski
Keyword(s):  
Basic Reproduction Number ◽  
Symptom Onset ◽  
Reproduction Number ◽  
Wide Spectrum ◽  
Control Measures ◽  
Current Evidence ◽  
The Novel ◽  
Novel Coronavirus ◽  
The Basic Reproduction Number

Interventions targeting symptomatic hosts and their contacts were successful in bringing the 2003 SARS pandemic under control. In contrast, the COVID-19 pandemic has been harder to contain, partly because of its wide spectrum of symptoms in infectious hosts. Current evidence suggests that individuals can transmit the novel coronavirus while displaying few symptoms. Here, we show that the proportion of infections arising from hosts with few symptoms at the start of an outbreak can, in combination with the basic reproduction number, indicate whether or not interventions targeting symptomatic hosts are likely to be effective. However, as an outbreak continues, the proportion of infections arising from hosts with few symptoms changes in response to control measures. A high proportion of infections from hosts with few symptoms after the initial stages of an outbreak is only problematic if the rate of new infections remains high. Otherwise, it can simply indicate that symptomatic transmissions are being prevented successfully. This should be considered when interpreting estimates of the extent of transmission from hosts with few COVID-19 symptoms.

scholarly journals Estimation of the Transmission Risk of the 2019-nCoV and Its Implication for Public Health Interventions

2020 ◽  
Vol 9 (2) ◽  
pp. 462 ◽  
Author(s):  
Biao Tang ◽  
Xia Wang ◽  
Qian Li ◽  
Nicola Luigi Bragazzi ◽  
Sanyi Tang ◽  
...  
Keyword(s):  
Reproduction Number ◽  
Transmission Risk ◽  
Sensitivity Analyses ◽  
Contact Tracing ◽  
The Novel ◽  
Intervention Measures ◽  
Novel Coronavirus ◽  
Restrictive Measures ◽  
And Control ◽  
Travel Restriction

Since the emergence of the first cases in Wuhan, China, the novel coronavirus (2019-nCoV) infection has been quickly spreading out to other provinces and neighboring countries. Estimation of the basic reproduction number by means of mathematical modeling can be helpful for determining the potential and severity of an outbreak and providing critical information for identifying the type of disease interventions and intensity. A deterministic compartmental model was devised based on the clinical progression of the disease, epidemiological status of the individuals, and intervention measures. The estimations based on likelihood and model analysis show that the control reproduction number may be as high as 6.47 (95% CI 5.71–7.23). Sensitivity analyses show that interventions, such as intensive contact tracing followed by quarantine and isolation, can effectively reduce the control reproduction number and transmission risk, with the effect of travel restriction adopted by Wuhan on 2019-nCoV infection in Beijing being almost equivalent to increasing quarantine by a 100 thousand baseline value. It is essential to assess how the expensive, resource-intensive measures implemented by the Chinese authorities can contribute to the prevention and control of the 2019-nCoV infection, and how long they should be maintained. Under the most restrictive measures, the outbreak is expected to peak within two weeks (since 23 January 2020) with a significant low peak value. With travel restriction (no imported exposed individuals to Beijing), the number of infected individuals in seven days will decrease by 91.14% in Beijing, compared with the scenario of no travel restriction.

scholarly journals Early dynamics of transmission and control of COVID-19: a mathematical modelling study

2020 ◽  
Author(s):  
Adam J Kucharski ◽  
Timothy W Russell ◽  
Charlie Diamond ◽  
Yang Liu ◽  
John Edmunds ◽  
...  
Keyword(s):  
Reproduction Number ◽  
Control Measures ◽  
Transmission Model ◽  
The Novel ◽  
Transmission Potential ◽  
Travel Restrictions ◽  
Gates Foundation ◽  
Novel Coronavirus ◽  
And Control ◽  
Over Time

AbstractBackgroundAn outbreak of the novel coronavirus SARS-CoV-2 has led to 46,997 confirmed cases as of 13th February 2020. Understanding the early transmission dynamics of the infection and evaluating the effectiveness of control measures is crucial for assessing the potential for sustained transmission to occur in new areas.MethodsWe combined a stochastic transmission model with data on cases of novel coronavirus disease (COVID-19) in Wuhan and international cases that originated in Wuhan to estimate how transmission had varied over time during January and February 2020. Based on these estimates, we then calculated the probability that newly introduced cases might generate outbreaks in other areas.FindingsWe estimated that the median daily reproduction number, Rt, declined from 2.35 (95% CI: 1.15-4.77) one week before travel restrictions were introduced on 23rd January to 1.05 (95% CI: 0.413-2.39) one week after. Based on our estimates of Rt,we calculated that in locations with similar transmission potential as Wuhan in early January, once there are at least four independently introduced cases, there is a more than 50% chance the infection will establish within that population.InterpretationOur results show that COVID-19 transmission likely declined in Wuhan during late January 2020, coinciding with the introduction of control measures. As more cases arrive in international locations with similar transmission potential to Wuhan pre-control, it is likely many chains of transmission will fail to establish initially, but may still cause new outbreaks eventually.FundingWellcome Trust (206250/Z/17/Z, 210758/Z/18/Z), HDR UK (MR/S003975/1), Gates Foundation (INV-003174), NIHR (16/137/109)

scholarly journals The Novel Coronavirus, 2019-nCoV, is Highly Contagious and More Infectious Than Initially Estimated

2020 ◽  
Author(s):  
Steven Sanche ◽  
Yen Ting Lin ◽  
Chonggang Xu ◽  
Ethan Romero-Severson ◽  
Nick Hengartner ◽  
...  
Keyword(s):  
Case Reports ◽  
Individual Case ◽  
Control Measures ◽  
Basic Reproductive Number ◽  
Contact Tracing ◽  
Reproductive Number ◽  
The Novel ◽  
Transmission Potential ◽  
Novel Coronavirus ◽  
Strong Control

AbstractThe novel coronavirus (2019-nCoV) is a recently emerged human pathogen that has spread widely since January 2020. Initially, the basic reproductive number, R0, was estimated to be 2.2 to 2.7. Here we provide a new estimate of this quantity. We collected extensive individual case reports and estimated key epidemiology parameters, including the incubation period. Integrating these estimates and high-resolution real-time human travel and infection data with mathematical models, we estimated that the number of infected individuals during early epidemic double every 2.4 days, and the R0 value is likely to be between 4.7 and 6.6. We further show that quarantine and contact tracing of symptomatic individuals alone may not be effective and early, strong control measures are needed to stop transmission of the virus.One-sentence summaryBy collecting and analyzing spatiotemporal data, we estimated the transmission potential for 2019-nCoV.

scholarly journals Effective Reproduction Number and Dispersion under Contact Tracing and Lockdown on COVID-19 in Karnataka

2020 ◽  
Author(s):  
Siva Athreya ◽  
Nitya Gadhiwala ◽  
Abhiti Mishra
Keyword(s):  
Individual Variation ◽  
Reproduction Number ◽  
Contact Tracing ◽  
The Novel ◽  
Secondary Infections ◽  
The Government ◽  
Novel Coronavirus

We analyze the data provided in the Novel Coronavirus (COVID-19) media bulletins of the Government of Karnataka. We classify the patients of COVID-19 into clusters and study the Reproduction number and Dispersion for eight specific clusters. We find that it is uniformly less than one, indicating the benefits of contact tracing, lockdown and quarantine measures. However, the Dispersion is low indicating individual variation in secondary infections and the occurrence of Super-spreading events. Finally, we analyze the surge in infections after 27th June and find it unlikely that it was caused solely by the large Migration in May and June 2020.

scholarly journals Response to the COVID-19 Epidemic: The Chinese Experience and Implications for Other Countries

2020 ◽  
Vol 17 (7) ◽  
pp. 2304 ◽  
Author(s):  
Wei Liu ◽  
Xiao-Guang Yue ◽  
Paul B. Tchounwou
Keyword(s):  
Control Measures ◽  
Business Community ◽  
Infection Prevention And Control ◽  
The Novel ◽  
Multiple Systems ◽  
The Public ◽  
Community Technology ◽  
Containment Measures ◽  
Novel Coronavirus ◽  
And Control

The ongoing outbreak of the novel coronavirus disease (COVID-19) that occurred in China is rapidly spreading globally. China’s bond and strict containment measures have been proved (in practice) to significantly reduce the spread of the epidemic. This was obtained through the use of emergency control measures in the epidemic areas and the integration of resources from multiple systems, including business, community, technology, education, and transportation, across the country. In order to better understand how China has managed to reduce the public health and economic impacts of the COVID-19 epidemic, this editorial systematically reviews the specific measures for infection prevention and control of the disease. The best practices for COVID-19 eradication in China provide evidence-based strategies that could be replicated in other countries.

scholarly journals COVID-19: An Updated Situation from Singapore

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Ke-Yan Loo ◽  
Angel Yun-Kuan Thye ◽  
Lydia Ngiik-Shiew Law ◽  
Jodi Woan Fei Law
Keyword(s):  
Public Health ◽  
Public Awareness ◽  
Disease Spread ◽  
Contact Tracing ◽  
The Novel ◽  
Vaccination Rates ◽  
The Public ◽  
Global Pandemic ◽  
The Government ◽  
Novel Coronavirus

Since the first reports of COVID-19 in 2019, the viral respiratory disease has spread across nations, sending the world into a global pandemic. The pandemic has heavily impacted the public health of the global community. Over 237 million confirmed cases have been reported, and more than 4.8 million lives have been lost due to the novel coronavirus. In Singapore, the government quickly took action in the early stages of the pandemic to limit the spread of the virus to protect the local communities from the disease. Singapore has been able to keep their confirmed COVID-19 cases and deaths at low numbers by implementing movement restrictions, raising public awareness, mask mandates, social distancing, providing free vaccinations for the public, and utilizing advancements in technology for contact tracing. The public has also upheld their social responsibility in cooperating with the Singaporean government to control the disease spread. COVID-19 is now moving into an endemic phase in Singapore as the vaccination rates are at an all-time high resulting in lower death rates, and the confirmed cases are primarily mild to asymptomatic. Singapore has set a precedent for how pandemics can be handled in the future to minimize mortality rates and protect public health.

scholarly journals Modelling the coronavirus disease (COVID-19) outbreak on the Diamond Princess ship using the public surveillance data from January 20 to February 20, 2020

2020 ◽  
Author(s):  
Shi Zhao ◽  
Peihua Cao ◽  
Daozhou Gao ◽  
Zian Zhuang ◽  
Marc KC Chong ◽  
...  
Keyword(s):  
Stochastic Model ◽  
Doubling Time ◽  
Reproduction Number ◽  
The Novel ◽  
The Public ◽  
Public Surveillance ◽  
Transmission Process ◽  
Large Dispersion ◽  
Novel Coronavirus ◽  
The Basic Reproduction Number

AbstractThe novel coronavirus disease 2019 (COVID-19) outbreak on the Diamond Princess ship has caused over 634 cases as of February 20, 2020. We model the transmission process on the ship with a stochastic model and estimate the basic reproduction number at 2.2 (95%CI: 2.1-2.4). We estimate a large dispersion parameter than other coronaviruses, which implies that the virus is difficult to go extinction. The epidemic doubling time is at 4.6 days (95%CI: 3.0-9.3), and thus timely actions were crucial. The lesson learnt on the ship is generally applicable in other settings.

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