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1.
Sci Rep ; 13(1): 8637, 2023 05 27.
Article in English | MEDLINE | ID: covidwho-20232625

ABSTRACT

The global COVID-19 pandemic brought considerable public and policy attention to the field of infectious disease modelling. A major hurdle that modellers must overcome, particularly when models are used to develop policy, is quantifying the uncertainty in a model's predictions. By including the most recent available data in a model, the quality of its predictions can be improved and uncertainties reduced. This paper adapts an existing, large-scale, individual-based COVID-19 model to explore the benefits of updating the model in pseudo-real time. We use Approximate Bayesian Computation (ABC) to dynamically recalibrate the model's parameter values as new data emerge. ABC offers advantages over alternative calibration methods by providing information about the uncertainty associated with particular parameter values and the resulting COVID-19 predictions through posterior distributions. Analysing such distributions is crucial in fully understanding a model and its outputs. We find that forecasts of future disease infection rates are improved substantially by incorporating up-to-date observations and that the uncertainty in forecasts drops considerably in later simulation windows (as the model is provided with additional data). This is an important outcome because the uncertainty in model predictions is often overlooked when models are used in policy.


Subject(s)
COVID-19 , Pandemics , Humans , Calibration , Bayes Theorem , COVID-19/epidemiology , Computer Simulation
2.
Sci Rep ; 13(1): 8929, 2023 06 01.
Article in English | MEDLINE | ID: covidwho-20232569

ABSTRACT

Even though the Covid-19 pandemic seems to be stagnating or decreasing across the world, a resurgence of the disease or the occurrence of other epidemics caused by the aerial dissemination of pathogenic biological agents cannot be ruled out. These agents, in particular the virions of the Covid-19 disease, are found in the particles originating from the sputum of infected symptomatic or asymptomatic people. In previous research, we made use of a three-dimensional Computational Fluid Dynamics (CFD) model to simulate particle transport and dispersion in ventilated semi-confined spaces. By way of illustration, we considered a commuter train coach in which an infected passenger emitted droplets (1 and 10 µm) and drops (100 and 1000 µm) while breathing and coughing. Using an Eulerian approach and a Lagrangian approach, we modelled the dispersion of the particles in the turbulent flow generated by the ventilation of the coach. The simulations returned similar results from both approaches and clearly demonstrated the very distinct aerodynamics of the aerosol of airborne droplets and, at the other end of the spectrum, of drops falling or behaving like projectiles depending on their initial velocity. That numerical study considered passengers without protective masks. In this new phase of research, we first used literature data to develop a model of a typical surgical mask for use on a digital manikin representing a human. Next, we resumed the twin experiment of the railway coach, but this time, the passengers (including the infected one) were provided with surgical masks. We compared the spatial and temporal distributions of the particles depending on whether the spreader passenger wore a mask at all, and whether the mask was perfectly fitted (without leaks) or worn loosely (with leaks). Beyond demonstrating the obvious value of wearing a mask in limiting the dissemination of particles, our model and our simulations allow a quantification of the ratio of particles suspended in the coach depending on whether the infected passenger wears a mask or not. Moreover, the calculations carried out constitute only one illustrative application among many others, not only in public transport, but in any other public or private ventilated space on the basis of the same physical models and digital twins of the places considered. CFD therefore makes it possible to estimate the criticality of the occupation of places by people with or without a mask and to recommend measures in order to limit aerial contamination by any kind of airborne pathogen, such as the virions of Covid-19.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Pandemics , Respiratory Aerosols and Droplets , Computer Simulation
3.
Sci Total Environ ; 891: 164694, 2023 Sep 15.
Article in English | MEDLINE | ID: covidwho-20237880

ABSTRACT

Since the outbreak of the COVID-19 pandemic, many previous studies using computational fluid dynamics (CFD) have focused on the dynamics of air masses, which are believed to be the carriers of respiratory diseases, in enclosed indoor environments. Although outdoor air may seem to provide smaller exposure risks, it may not necessarily offer adequate ventilation that varies with different micro-climate settings. To comprehensively assess the fluid dynamics in outdoor environments and the efficiency of outdoor ventilation, we simulated the outdoor transmission of a sneeze plume in "hot spots" or areas in which the air is not quickly ventilated. We began by simulating the airflow over buildings at the University of Houston using an OpenFOAM computational fluid dynamics solver that utilized the 2019 seasonal atmospheric velocity profile from an on-site station. Next, we calculated the length of time an existing fluid is replaced by new fresh air in the domain by defining a new variable and selecting the hot spots. Finally, we conducted a large-eddy simulation of a sneeze in outdoor conditions and then simulated a sneeze plume and particles in a hot spot. The results show that fresh incoming air takes as long as 1000 s to ventilate the hot spot area in some specific regions on campus. We also found that even the slightest upward wind causes a sneeze plume to dissipate almost instantaneously at lower elevations. However, downward wind provides a stable condition for the plume, and forward wind can carry a plume even beyond six feet, the recommended social distance for preventing infection. Additionally, the simulation of sneeze droplets shows that the majority of the particles adhered to the ground or body immediately, and airborne particles can be transported more than six feet, even in a minimal amount of ambient air.


Subject(s)
Air Pollution, Indoor , COVID-19 , Humans , Air Pollution, Indoor/analysis , Pandemics , COVID-19/epidemiology , Computer Simulation , Wind
4.
Int J Mol Sci ; 24(11)2023 May 25.
Article in English | MEDLINE | ID: covidwho-20237163

ABSTRACT

Since the outbreak of the pandemic respiratory virus SARS-CoV-2 (COVID-19), academic communities and governments/private companies have used several detection techniques based on gold nanoparticles (AuNPs). In this emergency context, colloidal AuNPs are highly valuable easy-to-synthesize biocompatible materials that can be used for different functionalization strategies and rapid viral immunodiagnosis. In this review, the latest multidisciplinary developments in the bioconjugation of AuNPs for the detection of SARS-CoV-2 virus and its proteins in (spiked) real samples are discussed for the first time, with reference to the optimal parameters provided by three approaches: one theoretical, via computational prediction, and two experimental, using dry and wet chemistry based on single/multistep protocols. Overall, to achieve high specificity and low detection limits for the target viral biomolecules, optimal running buffers for bioreagent dilutions and nanostructure washes should be validated before conducting optical, electrochemical, and acoustic biosensing investigations. Indeed, there is plenty of room for improvement in using gold nanomaterials as stable platforms for ultrasensitive and simultaneous "in vitro" detection by the untrained public of the whole SARS-CoV-2 virus, its proteins, and specific developed IgA/IgM/IgG antibodies (Ab) in bodily fluids. Hence, the lateral flow assay (LFA) approach is a quick and judicious solution to combating the pandemic. In this context, the author classifies LFAs according to four generations to guide readers in the future development of multifunctional biosensing platforms. Undoubtedly, the LFA kit market will continue to improve, adapting researchers' multidetection platforms for smartphones with easy-to-analyze results, and establishing user-friendly tools for more effective preventive and medical treatments.


Subject(s)
COVID-19 , Metal Nanoparticles , Humans , SARS-CoV-2 , COVID-19/diagnosis , Gold , Antibodies, Viral , Immunoglobulin A , Sensitivity and Specificity , Computer Simulation , Immunoassay/methods , COVID-19 Testing
5.
J Nurs Educ ; 62(6): 364-373, 2023 Jun.
Article in English | MEDLINE | ID: covidwho-20243500

ABSTRACT

AIM: The purpose of this article was to evaluate the ability of an interactive virtual reality (VR) platform guided by standards of best practice to provide an effective immersive learning environment. We specifically evaluated usability of the platform and learners' perceptions of the experience. BACKGROUND: A variety of strategies are needed to train a highly competent nursing workforce. METHODS: We conducted a quantitative cross-sectional study to evaluate the VR experience using the System Usability Scale (SUS)® and the Simulation Effectiveness Tool-Modified (SET-M). RESULTS: Post-simulation evaluations were completed by 127 prelicensure and 28 advanced practice students. On the SUS scale, students found the overall VR system easy to navigate, and on the SET-M, they rated the VR experience positively. CONCLUSION: Immersive technology such as VR with a defined curriculum and facilitated debriefing can be valuable for student learning and may ultimately effect patient care. [J Nurs Educ. 2023;62(6):364-373.].


Subject(s)
Education, Nursing , Virtual Reality , Humans , Cross-Sectional Studies , Learning , Computer Simulation
6.
Comput Methods Programs Biomed ; 236: 107526, 2023 Jun.
Article in English | MEDLINE | ID: covidwho-20231106

ABSTRACT

BACKGROUND: We provide a compartmental model for the transmission of some contagious illnesses in a population. The model is based on partial differential equations, and takes into account seven sub-populations which are, concretely, susceptible, exposed, infected (asymptomatic or symptomatic), quarantined, recovered and vaccinated individuals along with migration. The goal is to propose and analyze an efficient computer method which resembles the dynamical properties of the epidemiological model. MATERIALS AND METHODS: A non-local approach is utilized for finding approximate solutions for the mathematical model. To that end, a non-standard finite-difference technique is introduced. The finite-difference scheme is a linearly implicit model which may be rewritten using a suitable matrix. Under suitable circumstances, the matrices representing the methodology are M-matrices. RESULTS: Analytically, the local asymptotic stability of the constant solutions is investigated and the next generation matrix technique is employed to calculate the reproduction number. Computationally, the dynamical consistency of the method and the numerical efficiency are investigated rigorously. The method is thoroughly examined for its convergence, stability, and consistency. CONCLUSIONS: The theoretical analysis of the method shows that it is able to maintain the positivity of its solutions and identify equilibria. The method's local asymptotic stability properties are similar to those of the continuous system. The analysis concludes that the numerical model is convergent, stable and consistent, with linear order of convergence in the temporal domain and quadratic order of convergence in the spatial variables. A computer implementation is used to confirm the mathematical properties, and it confirms the ability in our scheme to preserve positivity, and identify equilibrium solutions and their local asymptotic stability.


Subject(s)
Models, Theoretical , Quarantine , Humans , Computer Simulation , Vaccination
7.
Math Biosci Eng ; 20(6): 11281-11312, 2023 Apr 26.
Article in English | MEDLINE | ID: covidwho-2327329

ABSTRACT

This study explores the use of numerical simulations to model the spread of the Omicron variant of the SARS-CoV-2 virus using fractional-order COVID-19 models and Haar wavelet collocation methods. The fractional order COVID-19 model considers various factors that affect the virus's transmission, and the Haar wavelet collocation method offers a precise and efficient solution to the fractional derivatives used in the model. The simulation results yield crucial insights into the Omicron variant's spread, providing valuable information to public health policies and strategies designed to mitigate its impact. This study marks a significant advancement in comprehending the COVID-19 pandemic's dynamics and the emergence of its variants. The COVID-19 epidemic model is reworked utilizing fractional derivatives in the Caputo sense, and the model's existence and uniqueness are established by considering fixed point theory results. Sensitivity analysis is conducted on the model to identify the parameter with the highest sensitivity. For numerical treatment and simulations, we apply the Haar wavelet collocation method. Parameter estimation for the recorded COVID-19 cases in India from 13 July 2021 to 25 August 2021 has been presented.


Subject(s)
COVID-19 , Humans , COVID-19/epidemiology , SARS-CoV-2 , Pandemics , Computer Simulation
8.
BMC Med Res Methodol ; 23(1): 120, 2023 05 19.
Article in English | MEDLINE | ID: covidwho-2324512

ABSTRACT

BACKGROUND: A considerable amount of various types of data have been collected during the COVID-19 pandemic, the analysis and understanding of which have been indispensable for curbing the spread of the disease. As the pandemic moves to an endemic state, the data collected during the pandemic will continue to be rich sources for further studying and understanding the impacts of the pandemic on various aspects of our society. On the other hand, naïve release and sharing of the information can be associated with serious privacy concerns. METHODS: We use three common but distinct data types collected during the pandemic (case surveillance tabular data, case location data, and contact tracing networks) to illustrate the publication and sharing of granular information and individual-level pandemic data in a privacy-preserving manner. We leverage and build upon the concept of differential privacy to generate and release privacy-preserving data for each data type. We investigate the inferential utility of privacy-preserving information through simulation studies at different levels of privacy guarantees and demonstrate the approaches in real-life data. All the approaches employed in the study are straightforward to apply. RESULTS: The empirical studies in all three data cases suggest that privacy-preserving results based on the differentially privately sanitized data can be similar to the original results at a reasonably small privacy loss ([Formula: see text]). Statistical inferences based on sanitized data using the multiple synthesis technique also appear valid, with nominal coverage of 95% confidence intervals when there is no noticeable bias in point estimation. When [Formula: see text] and the sample size is not large enough, some privacy-preserving results are subject to bias, partially due to the bounding applied to sanitized data as a post-processing step to satisfy practical data constraints. CONCLUSIONS: Our study generates statistical evidence on the practical feasibility of sharing pandemic data with privacy guarantees and on how to balance the statistical utility of released information during this process.


Subject(s)
COVID-19 , Humans , COVID-19/epidemiology , Privacy , Pandemics , Computer Simulation , Contact Tracing/methods
9.
Sci Prog ; 106(2): 368504231175328, 2023.
Article in English | MEDLINE | ID: covidwho-2325408

ABSTRACT

The outbreak of major public health emergencies such as the coronavirus epidemic has put forward new requirements for urban emergency management procedures. Accuracy and effective distribution model of emergency support materials, as an effective tool to inhibit the deterioration of the public health sector, have gradually become a research hotspot. The distribution of urban emergency support devices, under the secondary supply chain structure of "material transfer center-demand point," which may involve confusing demands, is studied to determine the actual situation of fuzzy requests under the impact of an epidemic outbreak. An optimization model of urban emergency support material distribution, based on Credibility theory, is first constructed. Then an improved sparrow search algorithm, ISSA, was designed by introducing Sobol sequence, Cauchy variation and bird swarm algorithm into the structure of the classical SSA. In addition, numerical validation and standard test set validation were carried out and the experimental results showed that the introduced improved strategy effectively improved the global search capability of the algorithm. Furthermore, simulation experiments are conducted, based on Shanghai, and the comparison with existing cutting-edge algorithms shows that the designed algorithm has stronger superiority and robustness. And the simulation results show that the designed algorithm can reduce vehicle cost by 4.83%, time cost by 13.80%, etc. compared to other algorithms. Finally, the impact of preference value on the distribution of emergency support materials is analyzed to help decision-makers to develop reasonable and effective distribution strategies according to the impact of major public health emergencies. The results of the study provide a practical reference for the solution of urban emergency support materials distribution problems.


Subject(s)
Emergencies , Public Health , Humans , China/epidemiology , Algorithms , Computer Simulation
10.
PLoS Comput Biol ; 19(2): e1010917, 2023 02.
Article in English | MEDLINE | ID: covidwho-2318361

ABSTRACT

Transmission of many communicable diseases depends on proximity contacts among humans. Modeling the dynamics of proximity contacts can help determine whether an outbreak is likely to trigger an epidemic. While the advent of commodity mobile devices has eased the collection of proximity contact data, battery capacity and associated costs impose tradeoffs between the observation frequency and scanning duration used for contact detection. The choice of observation frequency should depend on the characteristics of a particular pathogen and accompanying disease. We downsampled data from five contact network studies, each measuring participant-participant contact every 5 minutes for durations of four or more weeks. These studies included a total of 284 participants and exhibited different community structures. We found that for epidemiological models employing high-resolution proximity data, both the observation method and observation frequency configured to collect proximity data impact the simulation results. This impact is subject to the population's characteristics as well as pathogen infectiousness. By comparing the performance of two observation methods, we found that in most cases, half-hourly Bluetooth discovery for one minute can collect proximity data that allows agent-based transmission models to produce a reasonable estimation of the attack rate, but more frequent Bluetooth discovery is preferred to model individual infection risks or for highly transmissible pathogens. Our findings inform the empirical basis for guidelines to inform data collection that is both efficient and effective.


Subject(s)
Communicable Diseases , Epidemics , Humans , Communicable Diseases/epidemiology , Disease Outbreaks , Computer Simulation , Epidemiological Models
11.
Sci Rep ; 13(1): 5780, 2023 04 08.
Article in English | MEDLINE | ID: covidwho-2317150

ABSTRACT

Misinformation can have a profound detrimental impact on populations' wellbeing. In this large UK-based online experiment (n = 2430), we assessed the performance of false tag and inoculation interventions in protecting against different forms of misinformation ('variants'). While previous experiments have used perception- or intention-based outcome measures, we presented participants with real-life misinformation posts in a social media platform simulation and measured their engagement, a more ecologically valid approach. Our pre-registered mixed-effects models indicated that both interventions reduced engagement with misinformation, but inoculation was most effective. However, random differences analysis revealed that the protection conferred by inoculation differed across posts. Moderation analysis indicated that immunity provided by inoculation is robust to variation in individuals' cognitive reflection. This study provides novel evidence on the general effectiveness of inoculation interventions over false tags, social media platforms' current approach. Given inoculation's effect heterogeneity, a concert of interventions will likely be required for future safeguarding efforts.


Subject(s)
Communication , Disinformation , Infodemic , Psychological Techniques , Social Media , Humans , Computer Simulation , Intention , Internet , Psychotherapy/methods
12.
Cogn Sci ; 47(5): e13294, 2023 05.
Article in English | MEDLINE | ID: covidwho-2316745

ABSTRACT

People are known for good predictions in domains they have rich experience with, such as everyday statistics and intuitive physics. But how well can they predict for problems they lack experience with, such as the duration of an ongoing epidemic caused by a new virus? Amid the first wave of COVID-19 in China, we conducted an online diary study, asking each of over 400 participants to predict the remaining duration of the epidemic, once per day for 14 days. Participants' predictions reflected a reasonable use of publicly available information but were meanwhile biased, subject to the influence of negative affect and future time perspectives. Computational modeling revealed that participants neither relied on prior distributions of epidemic durations as in inferring everyday statistics, nor on mechanistic simulations of epidemic dynamics as in computing intuitive physics. Instead, with minimal experience, participants' predictions were best explained by similarity-based generalization of the temporal pattern of epidemic statistics. In two control experiments, we further confirmed that such cognitive algorithm is not specific to the epidemic scenario and that minimal and rich experience do lead to different prediction behaviors for the same observations. We conclude that people generalize patterns in recent history to predict the future under minimal experience.


Subject(s)
COVID-19 , Humans , COVID-19/epidemiology , Generalization, Psychological , Computer Simulation , China/epidemiology
13.
PLoS One ; 18(5): e0284759, 2023.
Article in English | MEDLINE | ID: covidwho-2316215

ABSTRACT

HIV/AIDS and COVID-19 co-infection is a common global health and socio-economic problem. In this paper, a mathematical model for the transmission dynamics of HIV/AIDS and COVID-19 co-infection that incorporates protection and treatment for the infected (and infectious) groups is formulated and analyzed. Firstly, we proved the non-negativity and boundedness of the co-infection model solutions, analyzed the single infection models steady states, calculated the basic reproduction numbers using next generation matrix approach and then investigated the existence and local stabilities of equilibriums using Routh-Hurwiz stability criteria. Then using the Center Manifold criteria to investigate the proposed model exhibited the phenomenon of backward bifurcation whenever its effective reproduction number is less than unity. Secondly, we incorporate time dependent optimal control strategies, using Pontryagin's Maximum Principle to derive necessary conditions for the optimal control of the disease. Finally, we carried out numerical simulations for both the deterministic model and the model incorporating optimal controls and we found the results that the model solutions are converging to the model endemic equilibrium point whenever the model effective reproduction number is greater than unity, and also from numerical simulations of the optimal control problem applying the combinations of all the possible protection and treatment strategies together is the most effective strategy to drastically minimizing the transmission of the HIV/AIDS and COVID-19 co-infection in the community under consideration of the study.


Subject(s)
Acquired Immunodeficiency Syndrome , COVID-19 , Coinfection , Humans , Acquired Immunodeficiency Syndrome/epidemiology , Coinfection/epidemiology , COVID-19/epidemiology , Computer Simulation , Models, Theoretical , Basic Reproduction Number
14.
J Math Biol ; 86(5): 77, 2023 04 19.
Article in English | MEDLINE | ID: covidwho-2315467

ABSTRACT

A discrete epidemic model with vaccination and limited medical resources is proposed to understand its underlying dynamics. The model induces a nonsmooth two dimensional map that exhibits a surprising array of dynamical behavior including the phenomena of the forward-backward bifurcation and period doubling route to chaos with feasible parameters in an invariant region. We demonstrate, among other things, that the model generates the above described phenomena as the transmission rate or the basic reproduction number of the disease gradually increases provided that the immunization rate is low, the vaccine failure rate is high and the medical resources are limited. Finally, the numerical simulations are provided to illustrate our main results.


Subject(s)
Epidemics , Vaccination , Computer Simulation , Epidemics/prevention & control , Basic Reproduction Number
15.
J Math Biol ; 86(5): 65, 2023 03 30.
Article in English | MEDLINE | ID: covidwho-2311810

ABSTRACT

The perception of susceptible individuals naturally lowers the transmission probability of an infectious disease but has been often ignored. In this paper, we formulate and analyze a diffusive SIS epidemic model with memory-based perceptive movement, where the perceptive movement describes a strategy for susceptible individuals to escape from infections. We prove the global existence and boundedness of a classical solution in an n-dimensional bounded smooth domain. We show the threshold-type dynamics in terms of the basic reproduction number [Formula: see text]: when [Formula: see text], the unique disease-free equilibrium is globally asymptotically stable; when [Formula: see text], there is a unique constant endemic equilibrium, and the model is uniformly persistent. Numerical analysis exhibits that when [Formula: see text], solutions converge to the endemic equilibrium for slow memory-based movement and they converge to a stable periodic solution when memory-based movement is fast. Our results imply that the memory-based movement cannot determine the extinction or persistence of infectious disease, but it can change the persistence manner.


Subject(s)
Communicable Diseases , Epidemics , Humans , Computer Simulation , Models, Biological , Communicable Diseases/epidemiology , Basic Reproduction Number , Disease Susceptibility/epidemiology
16.
Science ; 379(6631): 437-439, 2023 02 03.
Article in English | MEDLINE | ID: covidwho-2307802

ABSTRACT

The COVID-19 pandemic has highlighted important considerations for modeling future pandemics.


Subject(s)
COVID-19 , Epidemiological Models , Pandemics , Humans , COVID-19/epidemiology , COVID-19/prevention & control , Pandemics/prevention & control , Computer Simulation , Epidemiological Monitoring
17.
Math Biosci Eng ; 20(3): 4643-4672, 2023 01.
Article in English | MEDLINE | ID: covidwho-2307246

ABSTRACT

The coronavirus infectious disease (or COVID-19) is a severe respiratory illness. Although the infection incidence decreased significantly, still it remains a major panic for human health and the global economy. The spatial movement of the population from one region to another remains one of the major causes of the spread of the infection. In the literature, most of the COVID-19 models have been constructed with only temporal effects. In this paper, a vaccinated spatio-temporal COVID-19 mathematical model is developed to study the impact of vaccines and other interventions on the disease dynamics in a spatially heterogeneous environment. Initially, some of the basic mathematical properties including existence, uniqueness, positivity, and boundedness of the diffusive vaccinated models are analyzed. The model equilibria and the basic reproductive number are presented. Further, based upon the uniform and non-uniform initial conditions, the spatio-temporal COVID-19 mathematical model is solved numerically using finite difference operator-splitting scheme. Furthermore, detailed simulation results are presented in order to visualize the impact of vaccination and other model key parameters with and without diffusion on the pandemic incidence. The obtained results reveal that the suggested intervention with diffusion has a significant impact on the disease dynamics and its control.


Subject(s)
COVID-19 , Humans , COVID-19/epidemiology , COVID-19/prevention & control , Vaccination , Pandemics/prevention & control , Basic Reproduction Number , Computer Simulation
18.
J Appl Microbiol ; 130(1): 2-13, 2021 Jan.
Article in English | MEDLINE | ID: covidwho-2299665

ABSTRACT

AIMS: Providing a ready-to-use reverse transcriptase qPCR (RT-qPCR) method fully validated to detect the SARS-CoV-2 with a higher exclusivity than this shown by early published RT-qPCR designs. METHODS AND RESULTS: The specificity of the GPS™ CoVID-19 dtec-RT-qPCR test by analysis of sequence alignments was approached and compared with other RT-qPCR designs. The GPS™ CoVID-19 dtec-RT-qPCR test was validated following criteria of UNE/EN ISO 17025:2005 and ISO/IEC 15189:2012. Diagnostic validation was achieved by two independent reference laboratories, the Instituto de Salud Carlos III, (Madrid, Spain), the Public Health England (Colindale, London, UK), and received the label CE-IVD. The GPS design showed the highest exclusivity and passed all parameters of validation with strict acceptance criteria. Results from reference laboratories 100% correlated with these obtained by using reference methods and showed 100% of diagnostic sensitivity and specificity. CONCLUSIONS: The CE-IVD GPS™ CoVID-19 dtec-RT-qPCR test, available worldwide with full analytical and diagnostic validation, is the more exclusive for SARS-CoV-2 by far. SIGNIFICANCE AND IMPACT OF THE STUDY: Considering the CoVID-19 pandemic status, the exclusivity of RT-qPCR tests is crucial to avoid false positives due to related coronaviruses. This work provides of a highly specific and validated RT-qPCR method for detection of SARS-CoV-2, which represents a case of efficient transfer of technology successfully used since the pandemic was declared.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/diagnosis , SARS-CoV-2/isolation & purification , COVID-19 Nucleic Acid Testing/standards , Computer Simulation , Humans , Pandemics , Real-Time Polymerase Chain Reaction , Reproducibility of Results , SARS-CoV-2/classification , SARS-CoV-2/genetics , Sensitivity and Specificity , Sequence Alignment
19.
Psychol Med ; 53(5): 1850-1859, 2023 04.
Article in English | MEDLINE | ID: covidwho-2300681

ABSTRACT

BACKGROUND: Apathy, a disabling and poorly understood neuropsychiatric symptom, is characterised by impaired self-initiated behaviour. It has been hypothesised that the opportunity cost of time (OCT) may be a key computational variable linking self-initiated behaviour with motivational status. OCT represents the amount of reward which is foregone per second if no action is taken. Using a novel behavioural task and computational modelling, we investigated the relationship between OCT, self-initiation and apathy. We predicted that higher OCT would engender shorter action latencies, and that individuals with greater sensitivity to OCT would have higher behavioural apathy. METHODS: We modulated the OCT in a novel task called the 'Fisherman Game', Participants freely chose when to self-initiate actions to either collect rewards, or on occasion, to complete non-rewarding actions. We measured the relationship between action latencies, OCT and apathy for each participant across two independent non-clinical studies, one under laboratory conditions (n = 21) and one online (n = 90). 'Average-reward' reinforcement learning was used to model our data. We replicated our findings across both studies. RESULTS: We show that the latency of self-initiation is driven by changes in the OCT. Furthermore, we demonstrate, for the first time, that participants with higher apathy showed greater sensitivity to changes in OCT in younger adults. Our model shows that apathetic individuals experienced greatest change in subjective OCT during our task as a consequence of being more sensitive to rewards. CONCLUSIONS: Our results suggest that OCT is an important variable for determining free-operant action initiation and understanding apathy.


Subject(s)
Apathy , Adult , Humans , Cognition , Computer Simulation , Motivation , Reinforcement, Psychology
20.
Comput Biol Med ; 158: 106794, 2023 05.
Article in English | MEDLINE | ID: covidwho-2299952

ABSTRACT

COVID-19 is an infectious disease that presents unprecedented challenges to society. Accurately estimating the incubation period of the coronavirus is critical for effective prevention and control. However, the exact incubation period remains unclear, as COVID-19 symptoms can appear in as little as 2 days or as long as 14 days or more after exposure. Accurate estimation requires original chain-of-infection data, which may not be fully available from the original outbreak in Wuhan, China. In this study, we estimated the incubation period of COVID-19 by leveraging well-documented and epidemiologically informative chain-of-infection data collected from 10 regions outside the original Wuhan areas prior to February 10, 2020. We employed a proposed Monte Carlo simulation approach and nonparametric methods to estimate the incubation period of COVID-19. We also utilized manifold learning and related statistical analysis to uncover incubation relationships between different age and gender groups. Our findings revealed that the incubation period of COVID-19 did not follow general distributions such as lognormal, Weibull, or Gamma. Using proposed Monte Carlo simulations and nonparametric bootstrap methods, we estimated the mean and median incubation periods as 5.84 (95% CI, 5.42-6.25 days) and 5.01 days (95% CI 4.00-6.00 days), respectively. We also found that the incubation periods of groups with ages greater than or equal to 40 years and less than 40 years demonstrated a statistically significant difference. The former group had a longer incubation period and a larger variance than the latter, suggesting the need for different quarantine times or medical intervention strategies. Our machine-learning results further demonstrated that the two age groups were linearly separable, consistent with previous statistical analyses. Additionally, our results indicated that the incubation period difference between males and females was not statistically significant.


Subject(s)
COVID-19 , Male , Female , Humans , SARS-CoV-2 , Infectious Disease Incubation Period , Computer Simulation , China/epidemiology
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