scholarly journals A comprehensive estimation of country-level basic reproduction numbers R0 for COVID-19: Regime regression can automatically estimate the end of the exponential phase in epidemic data

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254145
Author(s):  
John L. Spouge
Keyword(s):  
Exponential Growth ◽  
Age Groups ◽  
Infectious Agent ◽  
Exponential Phase ◽  
Exploratory Analysis ◽  
Susceptible Population ◽  
Country Level ◽  
Effective Contact ◽  
Reproduction Numbers ◽  
Growth Method

In a compartmental epidemic model, the initial exponential phase reflects a fixed interaction between an infectious agent and a susceptible population in steady state, so it determines the basic reproduction number R0 on its own. After the exponential phase, dynamic complexities like societal responses muddy the practical interpretation of many estimated parameters. The computer program ARRP, already available from sequence alignment applications, automatically estimated the end of the exponential phase in COVID-19 and extracted the exponential growth rate r for 160 countries. By positing a gamma-distributed generation time, the exponential growth method then yielded R0 estimates for COVID-19 in 160 countries. The use of ARRP ensured that the R0 estimates were largely freed from any dependency outside the exponential phase. The Prem matrices quantify rates of effective contact for infectious disease. Without using any age-stratified COVID-19 data, but under strong assumptions about the homogeneity of susceptibility, infectiousness, etc., across different age-groups, the Prem contact matrices also yielded theoretical R0 estimates for COVID-19 in 152 countries, generally in quantitative conflict with the R0 estimates derived from the exponential growth method. An exploratory analysis manipulating only the Prem contact matrices reduced the conflict, suggesting that age-groups under 20 years did not promote the initial exponential growth of COVID-19 as much as other age-groups. The analysis therefore supports tentatively and tardily, but independently of age-stratified COVID-19 data, the low priority given to vaccinating younger age groups. It also supports the judicious reopening of schools. The exploratory analysis also supports the possibility of suspecting differences in epidemic spread among different age-groups, even before substantial amounts of age-stratified data become available.

COVID-19 and India: what next?

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ramesh Behl ◽  
Manit Mishra
Keyword(s):  
Predictive Modeling ◽  
Tamil Nadu ◽  
Data Science ◽  
Reproduction Number ◽  
Objective Assessment ◽  
Case Fatality ◽  
Susceptible Population ◽  
Content Type ◽  
Effective Contact ◽  
Growth Method

Purpose The study aims to carry out predictive modeling based on publicly available COVID-19 data for the duration April 01, 2020 to June 20, 2020 pertaining to India and five of its most infected states: Maharashtra, Tamil Nadu, Delhi, Gujarat and Rajasthan. Design/methodology/approach The study leverages the susceptible, infected, recovered and dead (SIRD) epidemiological framework for predictive modeling. The basic reproduction number R0 is derived by an exponential growth method using RStudio package R0. The differential equations reflecting the SIRD model have been solved using Python 3.7.4 on the Jupyter Notebook platform. For visualization, Python Matplotlib 3.2.1 package is used. Findings The study offers insights on peak-date, peak number of COVID-19 infections and end-date pertaining to India and five of its states. Practical implications The results subtly indicate toward the amount of effort required to completely eliminate the infection. It could be leveraged by the political leadership and industry doyens for economic policy planning and execution. Originality/value The emergence of a clear picture about COVID-19 lifecycle is impossible without integrating data science algorithms and epidemiology theoretical framework. This study amalgamates these two disciplines to undertake predictive modeling based on COVID-19 data from India and five of its states. Population-specific granular and objective assessment of key parameters such as reproduction number (R0), susceptible population (S), effective contact rate (ß) and case-fatality rate (s) have been used to generate a visualization of COVID-19 lifecycle pattern for a critically affected population.

COVID-19 Epigenetics and Implications for Public Health

Coronaviruses ◽  
2020 ◽  
Vol 01 ◽  
Author(s):  
Verda Tunalıgil ◽  
Gülsen Meral ◽  
Ahmet Katı ◽  
Dhrubajyoti Chattopadhyay ◽  
Amit Kumar Mandal
Keyword(s):  
Chronic Conditions ◽  
Empirical Investigation ◽  
Age Groups ◽  
Infectious Agent ◽  
Well Being ◽  
Epigenetic Mechanisms ◽  
Age Group ◽  
Epigenetic Changes ◽  
Patient Groups ◽  
Epigenetic Processes

Abstract:: Epigenetic changes in COVID-19 host, a pandemic-causing infectious agent that globally incapacitated communities in varying complexities and capacities are discussed, proposing an analogy that epigenetic processes contribute to disease severity and elevate the risk for death from infection. Percentages of hospitalization, with and without intensive care, in the presence of diseases with increased ACE2 expression, were compared, based on the best available data. Further analysis compared two different age groups, 19-64 and ≥65 years of age. The COVID-19 disease is observed to be the most severe in the 65-and-higher-age group with preexisting chronic conditions. This observational study is a non-experimental empirical investigation of the outcomes of COVID-19 in different patient groups. Results are promising for conducting clinical trials with intervention groups. To ultimately succeed in disease prevention, researchers and clinicians must integrate epigenetic mechanisms to generate valid prescriptions for global well-being.

scholarly journals Analysis and Simulation of Epidemic COVID-19 Curves with the Verhulst Model Applied to Statistical Inhomogeneous Age Groups

2021 ◽  
Vol 11 (9) ◽  
pp. 4159
Author(s):  
Lode K. J. Vandamme ◽  
Paulo R. F. Rocha
Keyword(s):  
Mental Health ◽  
Exponential Growth ◽  
Characteristic Time ◽  
Age Groups ◽  
Recovery Phase ◽  
Limited Growth ◽  
Logistic Equations ◽  
Quantitative Understanding ◽  
Returning Travellers ◽  
Verhulst Model

Pandemic curves, such as COVID-19, often show multiple and unpredictable contamination peaks, often called second, third and fourth waves, which are separated by wide plateaus. Here, by considering the statistical inhomogeneity of age groups, we show a quantitative understanding of the different behaviour rules to flatten a pandemic COVID-19 curve and concomitant multi-peak recurrence. The simulations are based on the Verhulst model with analytical generalized logistic equations for the limited growth. From the log–lin plot, we observe an early exponential growth proportional to . The first peak is often τgrow @ 5 d. The exponential growth is followed by a recovery phase with an exponential decay proportional to . For the characteristic time holds: . Even with isolation, outbreaks due to returning travellers can result in a recurrence of multi-peaks visible on log–lin scales. The exponential growth for the first wave is faster than for the succeeding waves, with characteristic times, τ of about 10 d. Our analysis ascertains that isolation is an efficient method in preventing contamination and enables an improved strategy for scientists, governments and the general public to timely balance between medical burdens, mental health, socio-economic and educational interests.

scholarly journals Analysis of Dibenzothiophene Desulfurization in a Recombinant Pseudomonas putida Strain

2008 ◽  
Vol 75 (3) ◽  
pp. 875-877 ◽  
Author(s):  
Javier Calzada ◽  
Mar�a T. Zamarro ◽  
Almudena Alc�n ◽  
Victoria E. Santos ◽  
Eduardo D�az ◽  
...  
Keyword(s):  
Pseudomonas Putida ◽  
Exponential Growth ◽  
Exponential Phase ◽  
Cell Process ◽  
Growth Phases ◽  
Early Exponential Phase ◽  
Sharp Maximum ◽  
Resting Cell

ABSTRACT Biodesulfurization was monitored in a recombinant Pseudomonas putida CECT5279 strain. DszB desulfinase activity reached a sharp maximum at the early exponential phase, but it rapidly decreased at later growth phases. A model two-step resting-cell process combining sequentially P. putida cells from the late and early exponential growth phases was designed to significantly increase biodesulfurization.

Inequality in active ageing: evidence from a new individual-level index for European countries

2017 ◽  
Vol 39 (3) ◽  
pp. 541-567 ◽  
Author(s):  
MIKKEL BARSLUND ◽  
MARTEN VON WERDER ◽  
ASGHAR ZAIDI
Keyword(s):  
Age Groups ◽  
Positive Association ◽  
European Countries ◽  
Active Ageing ◽  
Unequal Distribution ◽  
Individual Level ◽  
Country Level ◽  
Challenges And Opportunities ◽  
Share Data ◽  
The Individual

ABSTRACTIn the context of emerging challenges and opportunities associated with population ageing, the study of inequality in active-ageing outcomes is critical to the design of appropriate and effective social policies. While there is much discussion about active ageing at the aggregate country level, little is known about inequality in active-ageing experiences within countries. Based on the existing literature on active ageing, this paper proposes an individual-level composite active ageing index based on Survey of Health, Ageing and Retirement in Europe (SHARE) data. The individual-level nature of the index allows us to analyse inequality in experiences of active ageing within selected European countries. One important motivation behind measuring active ageing at the individual level is that it allows for a better understanding of unequal experiences of ageing, which may otherwise be masked in aggregate-level measures of active ageing. Results show large differences in the distribution of individual-level active ageing across the 13 European countries covered and across age groups. Furthermore, there is a positive association between the country-level active ageing index and the equality of its distribution within a country. Hence, countries with the lowest average active ageing index tend to have the most unequal distribution in active-ageing experiences. For nine European countries, where temporal data are also available, we find that inequality in active-ageing outcomes decreased in the period 2004 to 2013.

scholarly journals Exposure to secondhand aerosol of electronic cigarettes in indoor settings in 12 European countries: data from the TackSHS survey

2020 ◽  
Vol 30 (1) ◽  
pp. 49-56 ◽  
Author(s):  
Beladenta Amalia ◽  
Xiaoqiu Liu ◽  
Alessandra Lugo ◽  
Marcela Fu ◽  
Anna Odone ◽  
...  
Keyword(s):  
Public Transportation ◽  
Electronic Cigarettes ◽  
Age Groups ◽  
Cross Sectional Study ◽  
European Countries ◽  
Cross Sectional ◽  
Individual Level ◽  
Country Level ◽  
Registration Number ◽  
Private Transportation

IntroductionExposure to secondhand aerosol from e-cigarette (SHA) may pose harmful effects to bystanders. This study aims to investigate the prevalence, duration and determinants of SHA exposure in various indoor settings in 12 European countries.MethodsIn 2017–2018, we conducted a cross-sectional study, the TackSHS survey, on a representative sample of the population aged ≥15 years in 12 European countries (Bulgaria, England, France, Germany, Greece, Ireland, Italy, Latvia, Poland, Portugal, Romania and Spain). We described the prevalence and duration of exposure to SHA in several indoor settings among 11 604 e-cigarette non-users. Individual-level and country-level characteristics associated with SHA exposure were also explored using multilevel logistic regression analyses.ResultsOverall, 16.0% of e-cigarette non-users were exposed to SHA in any indoor setting at least weekly, ranging from 4.3% in Spain to 29.6% in England. The median duration of SHA exposure among those who were exposed was 43 min/day. ‘Other indoor settings’ (eg, bar and restaurant) was reported as the place where most of e-cigarette non-users were exposed (8.3%), followed by workplace/educational venues (6.4%), home (5.8%), public transportation (3.5%) and private transportation (2.7%). SHA exposure was more likely to occur in certain groups of non-users: men, younger age groups, those with higher level of education, e-cigarette past users, current smokers, those perceiving SHA harmless and living in countries with a higher e-cigarette use prevalence.ConclusionsWe found inequalities of SHA exposure across and within European countries. Governments should consider extending their tobacco smoke-free legislation to e-cigarettes to protect bystanders, particularly vulnerable populations such as young people.Trial registration numberNCT02928536.

scholarly journals Systematic evaluation of Mycobacterium tuberculosis proteins for antigenic properties identifies Rv1485 and Rv1705c as potential protective subunit vaccine candidates

2020 ◽  
pp. IAI.00585-20
Author(s):  
Yaguo Wang ◽  
Zihui Li ◽  
Shucai Wu ◽  
Joy Fleming ◽  
Chuanyou Li ◽  
...  
Keyword(s):  
Immune Response ◽  
Mycobacterium Tuberculosis ◽  
Mononuclear Cells ◽  
Protective Efficacy ◽  
Age Groups ◽  
Infectious Agent ◽  
Systematic Evaluation ◽  
Limiting Factor ◽  
Peripheral Blood Mononuclear ◽  
Antigenic Properties

Lack of efficacious vaccines against Mycobacterium tuberculosis (MTB) infection is a limiting factor in the prevention and control of tuberculosis (TB), the leading cause of death from an infectious agent. Improvement or replacement of the BCG vaccine with one that reliably protects all age-groups is urgent. Concerns exist that antigens currently being evaluated are too homogeneous. To identify new protective antigens, we screened 1781 proteins from a high-throughput proteome-wide protein purification study for antigenic activity. Forty-nine antigens (34 previously unreported) induced antigen-specific IFN-γ release from peripheral blood mononuclear cells (PBMCs) derived from 4452 TB and suspected TB patients and 167 healthy donors. Three (Rv1485, Rv1705c and Rv1802) of the 20 antigens evaluated in a BALB/c mouse challenge model showed protective efficacy, reducing lung CFU counts by 66.2%, 75.8%, and 60%, respectively. Evaluation of IgG2a:IgG1 ratios and cytokine release indicated that Rv1485 and Rv1705c induce a protective Th1 immune response. Epitope analysis of PE/PPE protein Rv1705c, the strongest candidate, identified a dominant epitope in its extreme N-terminal domain accounting for 90% of its immune response. Systematic pre-clinical assessment of antigens Rv1485 and Rv1705c is warranted.

Learning in late career stages in Europe – gendered effects of retirement policies

2020 ◽  
pp. 1-23
Author(s):  
Kirsti Melesk
Keyword(s):  
Gender Differences ◽  
Age Groups ◽  
Older Age ◽  
European Countries ◽  
Retirement Age ◽  
Logistic Regression Models ◽  
Highly Educated ◽  
Country Level ◽  
Retirement Systems ◽  
Retirement Policies

Abstract Institutional contexts shape learning participation throughout the course of life. Combining micro-data on adult education from 26 European countries with country-level indicators on retirement systems in multi-level logistic regression models, the focus is on analysis of participation in non-formal learning among people aged 50–64 and its interactions with retirement policies. The analysis makes use of the largest sample of European countries used so far for exploring the issue. For the first time, gender differences in retirement policies are considered. The results imply that for all women and highly educated men, participation in non-formal training is higher when retirement age in the country is set at 65 years or higher. However, men with less education do not profit from a higher retirement age because their training participation remains unaffected by retirement policies. In the current analysis, training participation in older age groups remains unaffected by the generosity of pensions. The results outline gender differences in learning participation in older age groups. Also, after the age of 50, men with a low education are at particular risk of labour market exclusion and unemployment because the retirement age in European countries keeps rising and technological advancements make additional demands on workers’ skills.

scholarly journals Modeling Growth, Containment and Decay of the COVID-19 Epidemic in Italy

2020 ◽  
Vol 8 ◽  
Author(s):  
Francesco Capuano
Keyword(s):  
Exponential Growth ◽  
Compartment Model ◽  
Growth Behavior ◽  
Time Dependent ◽  
Model Parameters ◽  
Susceptible Population ◽  
Dependent Rate ◽  
Slow Decay ◽  
Cumulative Curve ◽  
Modeling Growth

A careful inspection of the cumulative curve of confirmed COVID-19 infections in Italy and in other hard-hit countries reveals three distinct phases: i) an initial exponential growth (unconstrained phase), ii) an algebraic, power-law growth (containment phase), and iii) a relatively slow decay. We propose a parsimonious compartment model based on a time-dependent rate of depletion of the susceptible population that captures all such phases for a plausible range of model parameters. The results suggest an intimate interplay between the growth behavior, the timing and implementation of containment strategies, and the subsequent saturation of the outbreak.

scholarly journals H-NS Represses Salmonella enterica Serovar Typhimurium dsbA Expression during Exponential Growth

2004 ◽  
Vol 186 (4) ◽  
pp. 910-918 ◽  
Author(s):  
C. V. Gallant ◽  
T. Ponnampalam ◽  
H. Spencer ◽  
J. C. D. Hinton ◽  
N. L. Martin
Keyword(s):  
Exponential Growth ◽  
Salmonella Enterica ◽  
Immunoblot Analysis ◽  
Exponential Phase ◽  
Exponential Growth Phase ◽  
Mobility Shift ◽  
Altered Expression ◽  
Serovar Typhimurium ◽  
In The Wild ◽  
Maximal Expression

ABSTRACT Disulfide bond formation catalyzed by disulfide oxidoreductases occurs in the periplasm and plays a major role in the proper folding and integrity of many proteins. In this study, we were interested in elucidating factors that influence the regulation of dsbA, a gene coding for the primary disulfide oxidoreductase found in Salmonella enterica serovar Typhimurium. Strains with mutations created by transposon mutagenesis were screened for strains with altered expression of dsbA. A mutant (NLM2173) was found where maximal expression of a dsbA::lacZ transcriptional fusion occurred in the exponential growth phase in contrast to that observed in the wild type where maximal expression occurs in stationary phase. Sequence analysis of NLM2173 demonstrated that the transposon had inserted upstream of the gene encoding H-NS. Western immunoblot analysis using H-NS and StpA antibodies showed decreased amounts of H-NS protein in NLM2173, and this reduction in H-NS correlated with an increase of StpA protein. Northern blot analysis with a dsbA-specific probe showed an increase in dsbA transcript during exponential phase of growth. Direct binding of H-NS to the dsbA promoter region was verified using purified H-NS in electrophoretic mobility shift assays. Thus, a reduction in H-NS protein is correlated with a derepression of dsbA in NLM2173, suggesting that H-NS normally plays a role in suppressing the expression of dsbA during exponential phase growth.

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