scholarly journals Modelling the Transmission Dynamics of COVID-19 in Six High-Burden Countries

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Azizur Rahman ◽  
Md Abdul Kuddus
Keyword(s):  
Older People ◽  
Disease Transmission ◽  
Transmission Rate ◽  
Control Strategies ◽  
Rank Correlation ◽  
Critical Parameters ◽  
High Burden ◽  
Susceptibility To Infection ◽  
The Usa ◽  
The Uk

The new Coronavirus Disease 19, officially known as COVID-19, originated in China in 2019 and has since spread worldwide. We presented an age-structured Susceptible-Latent-Mild-Critical-Removed (SLMCR) compartmental model of COVID-19 disease transmission with nonlinear incidence during the pandemic period. We provided the model calibration to estimate parameters with day-wise COVID-19 data, i.e., reported cases by worldometer from 15th February to 30th March 2020 in six high-burden countries, including Australia, Italy, Spain, the USA, the UK, and Canada. We estimate transmission rates for each country and found that the country with the highest transmission rate is Spain, which may increase the new cases and deaths than the other countries. We found that saturation infection negatively impacted the dynamics of COVID-19 cases in all the six high-burden countries. The study used a sensitivity analysis to identify the most critical parameters through the partial rank correlation coefficient method. We found that the transmission rate of COVID-19 had the most significant influence on prevalence. The prediction of new cases in COVID-19 until 30th April 2020 using the developed model was also provided with recommendations to control strategies of COVID-19. We also found that adults are more susceptible to infection than both children and older people in all six countries. However, in Italy, Spain, the UK, and Canada, older people show more susceptibility to infection than children, opposite to the case in Australia and the USA. The information generated from this study would be helpful to the decision-makers of various organisations across the world, including the Ministry of Health in Australia, Italy, Spain, the USA, the UK, and Canada, to control COVID-19.

scholarly journals Modelling the transmission dynamics of COVID-19 in six high burden countries

2020 ◽  
Author(s):  
Azizur Rahman ◽  
Md Abdul Kuddus
Keyword(s):  
Disease Transmission ◽  
Compartmental Model ◽  
Transmission Rate ◽  
Control Strategies ◽  
Rank Correlation ◽  
Decision Makers ◽  
High Burden ◽  
Epidemic Period ◽  
Partial Rank Correlation ◽  
Coefficient Method

AbstractThe new coronavirus disease, officially known as COVID-19, originated in China in 2019 and has since spread around the globe. We presented a modified Susceptible-Latent-Infected-Removed (SLIR) compartmental model of COVID-19 disease transmission with nonlinear incidence during the epidemic period. We provided the model calibration to estimate parameters with day wise corona virus (COVID-19) data i.e. reported cases by worldometer from the period of 15th February to 30th March, 2020 in six high burden countries including Australia, Italy, Spain, USA, UK and Canada. We estimate transmission rates for each countries and found that the highest transmission rate country in Spain, which may be increase the new cases and deaths in Spain than the other countries. Sensitivity analysis was used to identify the most important parameters through the partial rank correlation coefficient method. We found that the transmission rate of COVID-19 had the largest influence on the prevalence. We also provides the prediction of new cases in COVID-19 until May 18, 2020 using the developed model and recommends, control strategies of COVID-19. The information that we generated from this study would be useful to the decision makers of various organizations across the world including the Ministry of Health in Australia, Italy, Spain, USA, UK and Canada to control COVID-19.

scholarly journals Implications of a travel connectivity-based approach for infectious disease transmission risks in Oceania

BMJ Open ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. e046206
Author(s):  
Angela Cadavid Restrepo ◽  
Luis Furuya-Kanamori ◽  
Helen Mayfield ◽  
Eric Nilles ◽  
Colleen L Lau
Keyword(s):  
Infectious Disease ◽  
Disease Transmission ◽  
Control Strategies ◽  
Vulnerability Index ◽  
French Polynesia ◽  
International Travel ◽  
Emerging Pathogens ◽  
The World ◽  
The Usa ◽  
The Uk

IntroductionThe increase in international travel brought about by globalisation has enabled the rapid spread of emerging pathogens with epidemic and pandemic potential. While travel connectivity-based assessments may help understand patterns of travel network-mediated epidemics, such approaches are rarely carried out in sufficient detail for Oceania where air travel is the dominant method of transportation between countries.DesignTravel data from the Australian Bureau of Statistics, Stats NZ and the United Nations World Tourism Organization websites were used to calculate travel volumes in 2018 within Oceania and between Oceania and the rest of the world. The Infectious Disease Vulnerability Index (IDVI) was incorporated into the analysis as an indicator of each country’s capacity to contain an outbreak. Travel networks were developed to assess the spread of infectious diseases (1) into and from Oceania, (2) within Oceania and (3) between each of the Pacific Island Countries and Territories (PICTs) and their most connected countries.ResultsOceania was highly connected to countries in Asia, Europe and North America. Australia, New Zealand and several PICTs were highly connected to the USA and the UK (least vulnerable countries for outbreaks based on the IDVI), and to China (intermediate low vulnerable country). High variability was also observed between the PICTs in the geographical distribution of their international connections. The PICTs with the highest number of international connections were Fiji, French Polynesia, Guam and Papua New Guinea.ConclusionTravel connectivity assessments may help to accurately stratify the risk of infectious disease importation and outbreaks in countries depending on disease transmission in other parts of the world. This information is essential to track future requirements for scaling up and targeting outbreak surveillance and control strategies in Oceania.

scholarly journals Estimating asymptomatic, undetected and total cases for the COVID-19 outbreak in Wuhan: a mathematical modeling study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xi Huo ◽  
Jing Chen ◽  
Shigui Ruan
Keyword(s):  
Disease Transmission ◽  
Large Scale ◽  
Transmission Rate ◽  
Control Strategies ◽  
Herd Immunity ◽  
Antibody Prevalence ◽  
Screening Process ◽  
Vaccination Programs ◽  
Prevalence Level ◽  
The Impact

Abstract Background The COVID-19 outbreak in Wuhan started in December 2019 and was under control by the end of March 2020 with a total of 50,006 confirmed cases by the implementation of a series of nonpharmaceutical interventions (NPIs) including unprecedented lockdown of the city. This study analyzes the complete outbreak data from Wuhan, assesses the impact of these public health interventions, and estimates the asymptomatic, undetected and total cases for the COVID-19 outbreak in Wuhan. Methods By taking different stages of the outbreak into account, we developed a time-dependent compartmental model to describe the dynamics of disease transmission and case detection and reporting. Model coefficients were parameterized by using the reported cases and following key events and escalated control strategies. Then the model was used to calibrate the complete outbreak data by using the Monte Carlo Markov Chain (MCMC) method. Finally we used the model to estimate asymptomatic and undetected cases and approximate the overall antibody prevalence level. Results We found that the transmission rate between Jan 24 and Feb 1, 2020, was twice as large as that before the lockdown on Jan 23 and 67.6% (95% CI [0.584,0.759]) of detectable infections occurred during this period. Based on the reported estimates that around 20% of infections were asymptomatic and their transmission ability was about 70% of symptomatic ones, we estimated that there were about 14,448 asymptomatic and undetected cases (95% CI [12,364,23,254]), which yields an estimate of a total of 64,454 infected cases (95% CI [62,370,73,260]), and the overall antibody prevalence level in the population of Wuhan was 0.745% (95% CI [0.693%,0.814%]) by March 31, 2020. Conclusions We conclude that the control of the COVID-19 outbreak in Wuhan was achieved via the enforcement of a combination of multiple NPIs: the lockdown on Jan 23, the stay-at-home order on Feb 2, the massive isolation of all symptomatic individuals via newly constructed special shelter hospitals on Feb 6, and the large scale screening process on Feb 18. Our results indicate that the population in Wuhan is far away from establishing herd immunity and provide insights for other affected countries and regions in designing control strategies and planing vaccination programs.

scholarly journals Epidemic cycles driven by host behaviour

2014 ◽  
Vol 11 (99) ◽  
pp. 20140575 ◽  
Author(s):  
Benjamin M. Althouse ◽  
Laurent Hébert-Dufresne
Keyword(s):  
Sexual Behaviour ◽  
Disease Transmission ◽  
Control Strategies ◽  
Treponema Pallidum ◽  
Structured Populations ◽  
Behavioural Interventions ◽  
Sexually Transmitted ◽  
The Face ◽  
The Usa ◽  
Host Behaviour

Host immunity and demographics (the recruitment of susceptibles via birthrate) have been demonstrated to be a key determinant of the periodicity of measles, pertussis and dengue epidemics. However, not all epidemic cycles are from pathogens inducing sterilizing immunity or are driven by demographics. Many sexually transmitted infections are driven by sexual behaviour. We present a mathematical model of disease transmission where individuals can disconnect and reconnect depending on the infectious status of their contacts. We fit the model to historic syphilis ( Treponema pallidum ) and gonorrhea ( Neisseria gonorrhoeae ) incidence in the USA and explore potential intervention strategies against syphilis. We find that cycles in syphilis incidence can be driven solely by changing sexual behaviour in structured populations. Our model also explains the lack of similar cycles in gonorrhea incidence even if the two infections share the same propagation pathways. Our model similarly illustrates how sudden epidemic outbreaks can occur on time scales smaller than the characteristic demographic time scale of the population and that weaker infections can lead to more violent outbreaks. Behaviour also appears to be critical for control strategies as we found a bigger sensitivity to behavioural interventions than antibiotic treatment. Thus, behavioural interventions may play a larger role than previously thought, especially in the face of antibiotic resistance and low intervention efficacies.

scholarly journals Do computers increase older people’s inclusion and wellbeing?

2016 ◽  
Vol 20 (1) ◽  
pp. 6-11 ◽  
Author(s):  
Sue Holttum
Keyword(s):  
Older People ◽  
Computer Technology ◽  
Computer Use ◽  
Well Being ◽  
Content Type ◽  
Face To Face ◽  
Personal Meanings ◽  
The Usa ◽  
On Line ◽  
The Uk

Purpose – The purpose of this paper is to consider two recent studies on computer use by older people, who may become increasingly isolated due to infirmity and sensory impairments. Older people are less likely to use computer technology yet it has been suggested that it may help reduce isolation. These studies inquired into older people’s experience with computers. Design/methodology/approach – The first paper discussed here explored how a sample of older people in the USA acquired a computer and whether it contributed to their well-being. The second paper was about a similar study with a sample of older people in the UK. Findings – In the US sample, people who saw tablet computers being used by a friend were likely to purchase one. In the UK sample, people seemed to have had to overcome more fears of using computer technology, but in both samples, once initial difficulties were overcome, people were enthusiastic about using them. In both, people felt more able to keep up hobbies and interests through finding information or connecting with interest groups online, and able to keep connected with family members. Originality/value – In light of increasing migration of services and information to the internet, these studies explored the things that help and hinder older people in terms of using computers, in order to address the digital divide, whereby those unable to use them can be left isolated and with reduced information and support. These studies were able to explore personal meanings of computer use and specific fears and difficulties, which are important to understand in planning for training and support for older people who are not yet on line. They also demonstrated that, alongside face-to-face interaction, being online was experienced as reducing people’s isolation and enhancing their lives.

Morphological and fecundity traits of Culex mosquitoes caught in gravid traps in urban and rural Berkshire, UK

2015 ◽  
Vol 105 (5) ◽  
pp. 615-620 ◽  
Author(s):  
S. Townroe ◽  
A. Callaghan
Keyword(s):  
Disease Transmission ◽  
Culex Pipiens ◽  
Good Condition ◽  
Seasonal Abundance ◽  
Rural Populations ◽  
Seasonal Activity ◽  
Behavioural Characteristics ◽  
The Usa ◽  
Risk Of Disease ◽  
The Uk

AbstractCulex pipiens s.l. is one of the primary vectors of West Nile Virus in the USA and Continental Europe. The seasonal abundance and eco-behavioural characteristics of the typical form, Cx. pipiens pipiens, make it a key putative vector in Britain. Surveillance of Culex larvae and adults is essential to detect any changes to spatial and seasonal activity or morphological traits that may increase the risk of disease transmission. Here we report the use of the modified Reiter gravid box trap, which is commonly used in the USA but scarcely used in the UK, to assess its suitability as a tool for British female Culex mosquito surveillance. Trapping was carried out at 110 sites in urban and rural gardens in Berkshire in May, July and September 2013. We tested if reproductively active adult female Culex are more abundant in urban than rural gardens and if wing characteristic traits and egg raft size are influenced by location and seasonal variations. Gravid traps were highly selective for Culex mosquitoes, on average catching significantly more per trap in urban gardens (32.4 ± 6.2) than rural gardens (19.3 ± 4.0) and more in July than in May or September. The majority of females were caught alive in a good condition. Wing lengths were measured as an indicator of size. Females flying in September were significantly smaller than females in May or July. Further non-significant differences in morphology and fecundity between urban and rural populations were found that should be explored further across the seasons.

The Potential of Digital Symptom-based Screening to Reduce the Transmission of SARS-CoV-2: a Modelling Study (Preprint)

2021 ◽  
Author(s):  
Jan Multmeier ◽  
Maryam Montazeri ◽  
Nicola Vona ◽  
François Bergey ◽  
Alicia Mehl ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Healthcare Providers ◽  
Social Contact ◽  
Screening Tools ◽  
Sensitivity Analyses ◽  
Base Case ◽  
German Population ◽  
Adoption Rate ◽  
The Usa ◽  
The Uk

BACKGROUND Early efforts to control the COVID-19 pandemic have been focused on Non-Pharmaceutical Interventions (NPIs) in the absence of effective treatments or sufficient vaccine supply. While retrospective analyses and modeling studies confirmed that severe restrictions of social contacts, i.e., lockdowns, are most effective in reducing transmission of SARS-CoV-2, they incur large economic costs and mental health risks. Earlier detection of cases has also been proposed as an effective method of control, but studies have so far only considered enhanced laboratory testing. Digital applications have been developed which aim to identify possible cases of COVID-19 based on reported symptoms and risk factors. OBJECTIVE The aim of this study is to explore the effects of digital screening applications for COVID-19 on the transmission of SARS-CoV-2. METHODS Using an established epidemiological Susceptible-Exposed-Infectious-Recovered (SEIR) model for infectious disease transmission, we simulate the transmission of SARS-CoV-2 in Germany, the UK, and the USA for 366 days after the virus was introduced in the population. We study 4 scenarios: 1) no interventions (base case), 2) symptom-based self-isolation after consulting healthcare providers, 3) self-isolation using digital screening applications, and 4) severe social contact limitations (lockdown). We included sensitivity analyses for different ratios of infectiousness of pre-symptomatic cases compared to symptomatic cases, and different rates of adoption of digital screening tools. RESULTS Without any intervention, 74% of the German population would be infected with SARS-CoV-2 within the simulation period (UK: 76%, USA: 77%). Self-isolation of symptomatic cases would already slow the spread of the virus significantly and lead to only 18% of the German population being infected (UK: 17%, USA: 17%). Using a digital application could further reduce the infected population to 10% (UK: 9%, USA: 9%), compared to 3% under lockdown conditions. While the effectiveness of digital screening applications varies with the adoption rate, even a low adoption rate could significantly reduce transmission. In the case that pre-symptomatic cases are less infectious than symptomatic cases, the overall proportion of infected individuals in the population decreases, and the effectiveness of different interventions converges. CONCLUSIONS Digital symptom-based screening tools can substantially impact the transmission of SARS-CoV-2 and might be a viable element in strategies to control COVID-19 through NPIs.

scholarly journals Transmission dynamics of SARS-CoV-2 in a strictly-Orthodox Jewish community in the UK

2021 ◽  
Author(s):  
William Waites ◽  
Carl AB Pearson ◽  
Katherine M Gaskell ◽  
Thomas House ◽  
Lorenzo Pellis ◽  
...  
Keyword(s):  
Primary Schools ◽  
Transmission Rate ◽  
Religious Community ◽  
Individual Level ◽  
Susceptibility To Infection ◽  
Relative Contribution ◽  
Social Settings ◽  
Community Transmission ◽  
Serological Data ◽  
The Uk

Some social settings such as households and workplaces, have been identified as high risk for SARS-CoV-2 transmission. Identifying and quantifying the importance of these settings is critical for designing interventions. A tightly-knit religious community in the UK experienced a very large COVID-19 epidemic in 2020, reaching 64.3% seroprevalence within 10 months, and we surveyed this community both for serological status and individual-level attendance at particular settings. Using these data, and a network model of people and places represented as a stochastic graph rewriting system, we estimated the relative contribution of transmission in households, schools and religious institutions to the epidemic, and the relative risk of infection in each of these settings. All congregate settings were important for transmission, with some such as primary schools and places of worship having a higher share of transmission than others. We found that the model needed a higher general-community transmission rate for women (3.3-fold), and lower susceptibility to infection in children to recreate the observed serological data. The precise share of transmission in each place was related to assumptions about the internal structure of those places. Identification of key settings of transmission can allow public health interventions to be targeted at these locations.

Bring on the health economists: time for a rigorous evaluation of senior participative arts

2014 ◽  
Vol 18 (1) ◽  
pp. 4-9
Author(s):  
Clair Chapwell
Keyword(s):  
Older People ◽  
San Francisco ◽  
Low Income ◽  
Content Type ◽  
Winston Churchill ◽  
The Usa ◽  
Antidepressant Use ◽  
One Year ◽  
The Uk ◽  
Medicare Costs

Purpose – As our elderly population increases, scheduled to rise by 61 per cent in the next 20 years, a national panic has set in about what to do. Antidepressant use is on the rise, and the figures for loneliness and depression skyrocketing. So far, so normal and so very disheartening. The purpose of this paper is to make a radical plea to change our thinking about how the lives of our senior citizens are lived: bring on the health economists, and let us put some serious funding into studying the effects of participative arts on the lives of older people. Design/methodology/approach – This year the author was awarded a Winston Churchill Fellowship to study participative arts for older people in the USA. The author interviewed Professor Julene Johnson of University of California San Francisco, about “Community of Voices” an ambitious, well-funded five year programme which is launching 12 one-year choirs with low income, non-singers, after which findings will be rigorously tested. Findings – In the USA, proper evaluation of participative arts is being taken seriously as a means of whittling down massive Medicare costs. There is evaluation going on in the UK, but much of it is flawed, usually down to cost. Evaluations generally consist of questionnaires filled in by participants. Findings centre around the psychological arena, rather than physical aspects (balance, hospital visits). Originality/value – It is imperative that one starts thinking about participative arts for seniors in a scientific and serious way. The alternative – roomfuls of elders on antidepressants (the UK's antidepressant use was up 23 per cent between 2010 and 2011) does not bear thinking about.

scholarly journals Study on the COVID-19 infection status, prevention and control strategies among people entering Shenzhen

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xuan Zou ◽  
Zi-Qian Xu ◽  
Bi-Xin Wang ◽  
Jian-Fan He ◽  
Jing-Zhong Wang
Keyword(s):  
Management Strategy ◽  
Closed Loop ◽  
Control Strategies ◽  
High Risk Population ◽  
Imported Infection ◽  
Entry Time ◽  
Imported Cases ◽  
The Usa ◽  
The Uk ◽  
Close Contacts

Abstract Background The novel coronavirus disease 2019 (COVID-19) confirmed cases overseas have continued to rise in the last months, and many people overseas have chosen to return to China. This increases the risk of a large number of imported cases which may cause a relapse of the COVID-19 outbreak. In order to prevent imported infection, the Shenzhen government has implemented a closed-loop management strategy using nucleic acid testing (NAT) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and requiring 14 days of medical observation for individuals with an overseas tour history (Hong Kong, Macao, Taiwan province and other countries). Our study aims to describe the status of COVID-19 infection among people entering Shenzhen, and to evaluate the effect of the closed-loop management strategy. Methods We undertook a descriptive study and risk analysis by the entry time, time of reporting, and local confirmed cases in countries of origin. The NAT were completed in Shenzhen Center for Disease Control and Prevention (CDC), ten district-level CDCs, and fever clinics. Results A total of 86,844 people from overseas entered Shenzhen from January 1 to April 18, 2020; there were 39 imported COVID cases and 293 close contacts. The infection rate of people entering was 4.49‰ [95% Confidence interval (CI): 3.26‰–6.05‰]. Fourteen imported cases (35.9%) came from the UK, and nine (23.08%) came from the USA. People entering from the USA since March 9 or from the UK since March 13 are the high-risk population. As of July 17, there have been no new confirmed cases in Shenzhen for 153 days, and the numbers of confirmed case, close contacts, and asymptomatic cases are 0. Conclusions The closed-loop management has been effective in preventing imported infection and controlling domestic relapse. The distribution of entry time and report time for imported cases overseas was similar. This shows that it is important to implement closed-loop management at the port of entry.

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