A Modified Epidemiological Model to Understand the UnevenImpact of COVID-19 on Vulnerable Individuals and theApproaches Required to Help them Emerge from Lockdown (Preprint)

UNSTRUCTURED COVID-19 has shown a relatively low case fatality rate in young healthy individuals, with the majority of this group being asymptomatic or having mild symptoms. However, the severity of the disease among the elderly as well as in individuals with underlying health conditions has caused significant mortality rates worldwide. Understanding this variance amongst different sectors of society and modelling this will enable the different levels of risk to be determined to enable strategies to be applied to different groups. Long established compartmental epidemiological models like SIR and SEIR do not account for the variability encountered in the severity of the SARS-CoV-2 disease across different population groups. To overcome this limitation, it is proposed that a modified model, namely SEIR-v, through which the population is separated into two groups regarding their vulnerability to SARS-CoV2 is applied. This enables the analysis of the spread of the epidemic when different contention measures are applied to different groups in society regarding their vulnerability to the disease. A Monte Carlo simulation adopting the proposed SEIR-v model indicates a large number of deaths could be avoided by slightly decreasing the exposure of vulnerable groups to the disease. From this modelling a number of mechanisms are proposed to limit the exposure of vulnerable individuals to the disease in order to reduce the mortality rate among this group. One option could be the provision of a wristband to vulnerable people and those without a smartphone and contact-tracing app, filling the gap created by systems relying on smartphone apps only.

Download Full-text

A COVID-19-Based Modified Epidemiological Model and Technological Approaches to Help Vulnerable Individuals Emerge from the Lockdown in the UK

Sensors ◽

10.3390/s20174967 ◽

2020 ◽

Vol 20 (17) ◽

pp. 4967 ◽

Cited By ~ 1

Author(s):

Dario Ortega Anderez ◽

Eiman Kanjo ◽

Ganna Pogrebna ◽

Omprakash Kaiwartya ◽

Shane D. Johnson ◽

...

Keyword(s):

Case Fatality ◽

The Elderly ◽

Vulnerable Groups ◽

Contact Tracing ◽

Smartphone Apps ◽

Epidemiological Models ◽

Mean Values ◽

Vulnerable People ◽

Severity Of The Disease ◽

The Uk

COVID-19 has shown a relatively low case fatality rate in young healthy individuals, with the majority of this group being asymptomatic or having mild symptoms. However, the severity of the disease among the elderly as well as in individuals with underlying health conditions has caused significant mortality rates worldwide. Understanding this variance amongst different sectors of society and modelling this will enable the different levels of risk to be determined to enable strategies to be applied to different groups. Long-established compartmental epidemiological models like SIR and SEIR do not account for the variability encountered in the severity of the SARS-CoV-2 disease across different population groups. The objective of this study is to investigate how a reduction in the exposure of vulnerable individuals to COVID-19 can minimise the number of deaths caused by the disease, using the UK as a case study. To overcome the limitation of long-established compartmental epidemiological models, it is proposed that a modified model, namely SEIR-v, through which the population is separated into two groups regarding their vulnerability to SARS-CoV-2 is applied. This enables the analysis of the spread of the epidemic when different contention measures are applied to different groups in society regarding their vulnerability to the disease. A Monte Carlo simulation (100,000 runs) along the proposed SEIR-v model is used to study the number of deaths which could be avoided as a function of the decrease in the exposure of vulnerable individuals to the disease. The results indicate a large number of deaths could be avoided by a slight realistic decrease in the exposure of vulnerable groups to the disease. The mean values across the simulations indicate 3681 and 7460 lives could be saved when such exposure is reduced by 10% and 20% respectively. From the encouraging results of the modelling a number of mechanisms are proposed to limit the exposure of vulnerable individuals to the disease. One option could be the provision of a wristband to vulnerable people and those without a smartphone and contact-tracing app, filling the gap created by systems relying on smartphone apps only. By combining very dense contact tracing data from smartphone apps and wristband signals with information about infection status and symptoms, vulnerable people can be protected and kept safer.

Download Full-text

Similarity in Case Fatality Rates (CFR) of COVID-19/SARS-COV-2 in Italy and China

The Journal of Infection in Developing Countries ◽

10.3855/jidc.12600 ◽

2020 ◽

Vol 14 (02) ◽

pp. 125-128 ◽

Cited By ~ 150

Author(s):

Rossella Porcheddu ◽

Caterina Serra ◽

David Kelvin ◽

Nikki Kelvin ◽

Salvatore Rubino

Keyword(s):

Elderly Patients ◽

Point Of Care ◽

Case Fatality ◽

The Elderly ◽

Northern Italy ◽

Contact Tracing ◽

Level Of Care ◽

Large Clusters ◽

Local Transmission ◽

Potential Level

As of 28 February 2020, Italy had 888 cases of SARS-CoV-2 infections, with most cases in Northern Italy in the Lombardia and Veneto regions. Travel-related cases were the main source of COVID-19 cases during the early stages of the current epidemic in Italy. The month of February, however, has been dominated by two large clusters of outbreaks in Northern Italy, south of Milan, with mainly local transmission the source of infections. Contact tracing has failed to identify patient zero in one of the outbreaks. As of 28 February 2020, twenty-one cases of COVID-19 have died. Comparison between case fatality rates in China and Italy are identical at 2.3. Additionally, deaths are similar in both countries with fatalities in mostly the elderly with known comorbidities. It will be important to develop point-of-care devices to aid clinicians in stratifying elderly patients as early as possible to determine the potential level of care they will require to improve their chances of survival from COVID-19 disease.

Download Full-text

Hidden Threat During Quarantine and Transition Phase in Elderly: The Need for Special Precautions

Journal Of The Indonesian Medical Association ◽

10.47830/jinma-vol.70.10-2020-292 ◽

2020 ◽

Vol 70 (10) ◽

pp. 190-193

Author(s):

Maggie Nathania ◽

Diana Sunardi

Keyword(s):

Case Fatality Rate ◽

Middle Age ◽

Transmission Rate ◽

Case Fatality ◽

Risk Groups ◽

The Elderly ◽

Age Group ◽

Global Pandemic ◽

The World ◽

Severity Of The Disease

A global pandemic, COVID-19, has struck 216 countries with more than 9 million cases and 420.000 deaths. In Indonesia alone, 49.000 people have been infected with more than 2.000 deaths. To reduce the transmission rate and break the chain of transmission, various countries in the world require people to limit and mitigate activities outside the house, especially for high-risk groups: the elderly and groups with comorbidities. Although there is no age group protected from SARS-CoV-2 infection, the elderly group shows significantly higher mortality and severity of the disease when compared with young and middle age. Case fatality rate in the elderly ranges between 8% in patients aged ≥80 years, 8% in patients aged 70-79 years, and up to 49% in critical cases. Other studies also show that the average age of patients who need the intensive care unit (ICU) is older than patients who do not require ICU.

Download Full-text

COVID-19 Epidemic in Malaysia: Epidemic Progression, Challenges, and Response

Frontiers in Public Health ◽

10.3389/fpubh.2021.560592 ◽

2021 ◽

Vol 9 ◽

Author(s):

Jamal Hisham Hashim ◽

Mohammad Adam Adman ◽

Zailina Hashim ◽

Mohd Firdaus Mohd Radi ◽

Soo Chen Kwan

Keyword(s):

Communicable Disease ◽

Heart Diseases ◽

Nipah Virus ◽

Herd Immunity ◽

Case Fatality ◽

Movement Control ◽

Vulnerable Groups ◽

Contact Tracing ◽

Successful Implementation ◽

Hospital System

COVID-19 pandemic is the greatest communicable disease outbreak to have hit Malaysia since the 1918 Spanish Flu which killed 34,644 people or 1% of the population of the then British Malaya. In 1999, the Nipah virus outbreak killed 105 Malaysians, while the SARS outbreak of 2003 claimed only 2 lives. The ongoing COVID-19 pandemic has so far claimed over 100 Malaysian lives. There were two waves of the COVID-19 cases in Malaysia. First wave of 22 cases occurred from January 25 to February 15 with no death and full recovery of all cases. The ongoing second wave, which commenced on February 27, presented cases in several clusters, the biggest of which was the Sri Petaling Tabligh cluster with an infection rate of 6.5%, and making up 47% of all cases in Malaysia. Subsequently, other clusters appeared from local mass gatherings and imported cases of Malaysians returning from overseas. Healthcare workers carry high risks of infection due to the daily exposure and management of COVID-19 in the hospitals. However, 70% of them were infected through community transmission and not while handling patients. In vulnerable groups, the incidence of COVID-19 cases was highest among the age group 55 to 64 years. In terms of fatalities, 63% were reported to be aged above 60 years, and 81% had chronic comorbidities such as diabetes, hypertension, and heart diseases. The predominant COVID-19 strain in Malaysia is strain B, which is found exclusively in East Asia. However, strain A, which is mostly found in the USA and Australia, and strain C in Europe were also present. To contain the epidemic, Malaysia implemented a Movement Control Order (MCO) beginning on March 18 in 4 phases over 2 months, ending on May 12. In terms of economic impacts, Malaysia lost RM2.4 billion a day during the MCO period, with an accumulated loss of RM63 billion up to the end of April. Since May 4, Malaysia has relaxed the MCO and opened up its economic sector to relieve its economic burden. Currently, the best approach to achieving herd immunity to COVID-19 is through vaccination rather than by acquiring it naturally. There are at least two candidate vaccines which have reached the final stage of human clinical trials. Malaysia's COVID-19 case fatality rate is lower than what it is globally; this is due to the successful implementation of early preparedness and planning, the public health and hospital system, comprehensive contact tracing, active case detection, and a strict enhanced MCO.

Download Full-text

Role of efficient testing and contact tracing in mitigating the COVID-19 pandemic: a network modelling study

BMJ Open ◽

10.1136/bmjopen-2020-045886 ◽

2021 ◽

Vol 11 (7) ◽

pp. e045886

Author(s):

Yiying Hu ◽

Jianying Guo ◽

Guanqiao Li ◽

Xi Lu ◽

Xiang Li ◽

...

Keyword(s):

Real World ◽

Case Fatality ◽

Contact Tracing ◽

Secondary Outcome ◽

Time Interval ◽

Fatality Rate ◽

Real World Data ◽

Network Modelling ◽

World Data ◽

Quantitative Evidence

ObjectivesThis study quantified how the efficiency of testing and contact tracing impacts the spread of COVID-19. The average time interval between infection and quarantine, whether asymptomatic cases are tested or not, and initial delays to beginning a testing and tracing programme were investigated.SettingWe developed a novel individual-level network model, called CoTECT (Testing Efficiency and Contact Tracing model for COVID-19), using key parameters from recent studies to quantify the impacts of testing and tracing efficiency. The model distinguishes infection from confirmation by integrating a ‘T’ compartment, which represents infections confirmed by testing and quarantine. The compartments of presymptomatic (E), asymptomatic (I), symptomatic (Is), and death with (F) or without (f) test confirmation were also included in the model. Three scenarios were evaluated in a closed population of 3000 individuals to mimic community-level dynamics. Real-world data from four Nordic countries were also analysed.Primary and secondary outcome measuresSimulation result: total/peak daily infections and confirmed cases, total deaths (confirmed/unconfirmed by testing), fatalities and the case fatality rate. Real-world analysis: confirmed cases and deaths per million people.Results(1) Shortening the duration between Is and T from 12 to 4 days reduces infections by 85.2% and deaths by 88.8%. (2) Testing and tracing regardless of symptoms reduce infections by 35.7% and deaths by 46.2% compared with testing only symptomatic cases. (3) Reducing the delay to implementing a testing and tracing programme from 50 to 10 days reduces infections by 35.2% and deaths by 44.6%. These results were robust to sensitivity analysis. An analysis of real-world data showed that tests per case early in the pandemic are critical for reducing confirmed cases and the fatality rate.ConclusionsReducing testing delays will help to contain outbreaks. These results provide policymakers with quantitative evidence of efficiency as a critical value in developing testing and contact tracing strategies.

Download Full-text

COVID-19 in comparison with other emerging viral diseases: risk of geographic spread via travel

Tropical Diseases Travel Medicine and Vaccines ◽

10.1186/s40794-020-00129-9 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

A. Wilder-Smith

Keyword(s):

Reproduction Number ◽

Emerging Infectious Diseases ◽

Case Fatality ◽

The Elderly ◽

Air Travel ◽

Viral Diseases ◽

Fatality Rate ◽

The Past ◽

Geographic Spread ◽

Emerging Viral Diseases

Abstract Purpose of review The COVID-19 pandemic poses a major global health threat. The rapid spread was facilitated by air travel although rigorous travel bans and lockdowns were able to slow down the spread. How does COVID-19 compare with other emerging viral diseases of the past two decades? Recent findings Viral outbreaks differ in many ways, such as the individuals most at risk e.g. pregnant women for Zika and the elderly for COVID-19, their vectors of transmission, their fatality rate, and their transmissibility often measured as basic reproduction number. The risk of geographic spread via air travel differs significantly between emerging infectious diseases. Summary COVID-19 is not associated with the highest case fatality rate compared with other emerging viral diseases such as SARS and Ebola, but the combination of a high reproduction number, superspreading events and a globally immunologically naïve population has led to the highest global number of deaths in the past 20 decade compared to any other pandemic.

Download Full-text

Exploring the effectiveness of a COVID-19 contact tracing app using an agent-based model

Scientific Reports ◽

10.1038/s41598-020-79000-y ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Jonatan Almagor ◽

Stefano Picascia

Keyword(s):

High Rate ◽

Contact Tracing ◽

Agent Based Model ◽

Agent Based ◽

The Social ◽

Behavioural Factors ◽

The Impact ◽

Different Levels ◽

User Rate

AbstractA contact-tracing strategy has been deemed necessary to contain the spread of COVID-19 following the relaxation of lockdown measures. Using an agent-based model, we explore one of the technology-based strategies proposed, a contact-tracing smartphone app. The model simulates the spread of COVID-19 in a population of agents on an urban scale. Agents are heterogeneous in their characteristics and are linked in a multi-layered network representing the social structure—including households, friendships, employment and schools. We explore the interplay of various adoption rates of the contact-tracing app, different levels of testing capacity, and behavioural factors to assess the impact on the epidemic. Results suggest that a contact tracing app can contribute substantially to reducing infection rates in the population when accompanied by a sufficient testing capacity or when the testing policy prioritises symptomatic cases. As user rate increases, prevalence of infection decreases. With that, when symptomatic cases are not prioritised for testing, a high rate of app users can generate an extensive increase in the demand for testing, which, if not met with adequate supply, may render the app counterproductive. This points to the crucial role of an efficient testing policy and the necessity to upscale testing capacity.

Download Full-text

Spectral Decomposition of the Flow and Characterization of the Sound Signals through Stenoses with Different Levels of Severity

Bioengineering ◽

10.3390/bioengineering8030041 ◽

2021 ◽

Vol 8 (3) ◽

pp. 41

Author(s):

Fardin Khalili ◽

Peshala T. Gamage ◽

Amirtahà Taebi ◽

Mark E. Johnson ◽

Randal B. Roberts ◽

...

Keyword(s):

Pressure Fluctuations ◽

High Energy ◽

Sound Sources ◽

Severity Level ◽

Non Invasive ◽

Flow Through ◽

Severity Of The Disease ◽

Proper Orthogonal ◽

Different Levels

Treatments of atherosclerosis depend on the severity of the disease at the diagnosis time. Non-invasive diagnosis techniques, capable of detecting stenosis at early stages, are essential to reduce associated costs and mortality rates. We used computational fluid dynamics and acoustics analysis to extensively investigate the sound sources arising from high-turbulent fluctuating flow through stenosis. The frequency spectral analysis and proper orthogonal decomposition unveiled the frequency contents of the fluctuations for different severities and decomposed the flow into several frequency bandwidths. Results showed that high-intensity turbulent pressure fluctuations appeared inside the stenosis for severities above 70%, concentrated at plaque surface, and immediately in the post-stenotic region. Analysis of these fluctuations with the progression of the stenosis indicated that (a) there was a distinct break frequency for each severity level, ranging from 40 to 230 Hz, (b) acoustic spatial-frequency maps demonstrated the variation of the frequency content with respect to the distance from the stenosis, and (c) high-energy, high-frequency fluctuations existed inside the stenosis only for severe cases. This information can be essential for predicting the severity level of progressive stenosis, comprehending the nature of the sound sources, and determining the location of the stenosis with respect to the point of measurements.

Download Full-text

Estimates and Determinants of SARS-Cov-2 Seroprevalence and Infection Fatality Ratio Using Latent Class Analysis: The Population-Based Tirschenreuth Study in the Hardest-Hit German County in Spring 2020

Viruses ◽

10.3390/v13061118 ◽

2021 ◽

Vol 13 (6) ◽

pp. 1118

Author(s):

Ralf Wagner ◽

David Peterhoff ◽

Stephanie Beileke ◽

Felix Günther ◽

Melanie Berr ◽

...

Keyword(s):

Latent Class Analysis ◽

Latent Class ◽

Care Home ◽

Case Fatality ◽

The Elderly ◽

Population Based ◽

Class Analysis ◽

Population Based Study ◽

Targeted Testing ◽

June July

SARS-CoV-2 infection fatality ratios (IFR) remain controversially discussed with implications for political measures. The German county of Tirschenreuth suffered a severe SARS-CoV-2 outbreak in spring 2020, with particularly high case fatality ratio (CFR). To estimate seroprevalence, underreported infections, and IFR for the Tirschenreuth population aged ≥14 years in June/July 2020, we conducted a population-based study including home visits for the elderly, and analyzed 4203 participants for SARS-CoV-2 antibodies via three antibody tests. Latent class analysis yielded 8.6% standardized county-wide seroprevalence, a factor of underreported infections of 5.0, and 2.5% overall IFR. Seroprevalence was two-fold higher among medical workers and one third among current smokers with similar proportions of registered infections. While seroprevalence did not show an age-trend, the factor of underreported infections was 12.2 in the young versus 1.7 for ≥85-year-old. Age-specific IFRs were <0.5% below 60 years of age, 1.0% for age 60–69, and 13.2% for age 70+. Senior care homes accounted for 45% of COVID-19-related deaths, reflected by an IFR of 7.5% among individuals aged 70+ and an overall IFR of 1.4% when excluding senior care home residents from our computation. Our data underscore senior care home infections as key determinant of IFR additionally to age, insufficient targeted testing in the young, and the need for further investigations on behavioral or molecular causes of the fewer infections among current smokers.

Download Full-text