The COVID-19 pandemic as inspiration to reconsider epidemic models: A novel approach to spatially homogeneous epidemic spread modeling.

Epidemic spread models are useful tools to study the spread and the effectiveness of the interventions at a population level, to an epidemic. The workhorse of spatially homogeneous class models is the SIR-type ones comprising ordinary differential equations for the unknown state variables. The transition between different states is expressed through rate functions. Inspired by -but not restricted to- features of the COVID-19 pandemic, a new framework for modeling a disease spread is proposed. The main concept refers to the assignment of properties to each individual person as regards his response to the disease. A multidimensional distribution of these properties represents the whole population. The temporal evolution of this distribution is the only dependent variable of the problem. All other variables can be extracted by post-processing of this distribution. It is noteworthy that the new concept allows an improved consideration of vaccination modeling because it recognizes vaccination as a modifier of individuals response to the disease and not as a means for individuals to totally defeat the disease. At the heart of the new approach is an infection age model engaging a sharp cut-off. This model is analyzed in detail, and it is shown to admit self-similar solutions. A hierarchy of models based on the new approach, from a generalized one to a specific one with three dominant properties, is derived. The latter is implemented as an example and indicative results are presented and discussed. It appears that the new framework is general and versatile enough to simulate disease spread processes and to predict the evolution of several variables of the population during this spread.

Detecting SARS-CoV-2 lineages and mutational load in municipal wastewater and a use-case in the metropolitan area of Thessaloniki, Greece.

The COVID-19 pandemic represents an unprecedented global crisis necessitating novel approaches for, amongst others, early detection of emerging variants relating to the evolution and spread of the virus. Recently, the detection of SARS-CoV-2 RNA in wastewater has emerged as a useful tool to monitor the prevalence of the virus in the community. Here, we propose a novel methodology, called lineagespot, for the monitoring of mutations and the detection of SARS-CoV-2 lineages in wastewater samples using next-generation sequencing (NGS). Our proposed method was tested and evaluated using NGS data produced by the sequencing of 14 wastewater samples from the municipality of Thessaloniki, Greece, covering a 6-month period. The results showed the presence of SARS-CoV-2 variants in wastewater data. lineagespot was able to record the evolution and rapid domination of the Alpha variant (B.1.1.7) in the community, and allowed the correlation between the mutations evident through our approach and the mutations observed in patients from the same area and time periods. lineagespot is an open-source tool, implemented in R, and is freely available on GitHub and registered on bio.tools.

SARS-CoV-2 adsorption on suspended solids along a sewerage network: mathematical model formulation, sensitivity analysis, and parametric study.

Accounting for SARS-CoV-2 adsorption on solids suspended in wastewater is a necessary step towards the reliable estimation of virus shedding rate in a sewerage system, based on measurements performed at a terminal collection station, i.e., at the entrance of a wastewater treatment plant. This concept is extended herein to include several measurement stations across a city to enable the estimation of spatial distribution of virus shedding rate. This study presents a pioneer general model describing the most relevant physicochemical phenomena with a special effort to reduce the complicated algebra. This is performed both in the topology regime, introducing a discrete-continuous approach, and in the domain of independent variables, introducing a monodisperse moment method to reduce the dimensionality of the resulting population balance equations. The resulting simplified model consists of a large system of ordinary differential equations. A sensitivity analysis is performed with respect to some key parameters for a single pipe topology. Specific numerical techniques are employed for the integration of the model. Finally, a parametric case study for an indicative-yet realistic-sewerage piping system is performed to show how the model is applied to SARS-CoV-2 adsorption on wastewater solids in the presence of other competing species. This is the first model of this kind appearing in scientific literature and a first step towards setting up an inverse problem to assess the spatial distribution of virus shedding rate based on its concentration in wastewater.

The international initiatives of the collaboration between the Aristotle University of Thessaloniki School of Medicine, the Panhellenic Medical Association and the World Psychiatric Association, concerning mental health during the COVID-19 outbreak.

During the coronavirus disease 2019 (COVID-19) pandemic, all European countries were hit, but mortality rates were heterogenous, with some countries being hit very hard, while others including Greece had a much lower death rate during the first wave of spring 2020. The ultra-fast application of measures was probably the reason of this outstanding success. This outbreak is expected to trigger feelings of fear, worry, and stress, as responses to an extreme threat for the community and the individual. In addition, changes in social behavior, as well as in working conditions, daily habits and routine, are expected to impose further stress, especially with the expectation of an upcoming economic crisis and possible unemployment. In Greece, where the lockdown was extremely successful in terms of containing the outbreak, worries concerning the possible adverse effects on mental health were also predominant. A collaboration concerning mental health during the COVID-19 outbreak was established, between the Aristotle University School of Medicine, the Panhellenic Medical Association and the World Psychiatric Association. Two large multinational studies were launched, one concerning the general population and one university students. Students' mental health is an area of special interest, both because of the vulnerability of this age group as well as because any disruption during the time of the studies has profound long-term consequences in the lives of the individuals, and this might trigger feelings of fear, worry, and stress. According the results from the Greek arm of the students' study, during the lockdown, two-thirds of university students reported at least 'much' increase in anxiety, one third in depressive feelings and in 2.59% concerning suicidal thoughts. There was also a worsening of quality of life and deterioration of lifestyle issues. Major depression was present in 12.43% with an additional 13.46% experiencing severe distress. Beliefs in conspiracy theories enjoyed wide acceptance ranging from 20-68%, with students of law, literature, pedagogics, political sciences and related studies manifesting higher acceptance rates. Female sex and depression/dysphoria both independently but also in interaction were related to higher rates of such beliefs. The results of the Greek arm of the general population study suggested that during the lockdown, clinical depression was present in 9.31%, with an additional 8.5% experiencing severe distress. Increased anxious and depressive emotions (including subclinical cases) were present in more than 40% of the population. In persons with a previous history of depression, 23.31% experienced depression vs. 8.96% of cases without previous history, who were experiencing their first depressive episode. Family dynamics suggested that fewer conflicts and better quality of relationships were surprisingly related to higher anxiety and depressive emotions, higher rates of depression and distress, and greater rates of suicidal thoughts. Eventually, spiritual and religious affiliation could protect the individual from the emerging suicidal thoughts. As correlation does not imply causation, the results suggest that conspiracy theories could be either the cause of depression or on the contrary a coping mechanism against depression. After taking into consideration that also in the family environment the expression of anger seemed to be a protective factor, the most likely explanation could be that the beliefs in conspiracy theories are a coping and 'protective' mechanism against the emergence of depression. These studies were among the first published, they went deeper in the data collection and even led to the creation of a model with distinct stages for the development of mental disorders during the lockdown. The analysis of the international data will probably provide further insight into the prevalence of mental disorders and the universal but also culturally specific models and factors pertaining to their development. At the time this editorial was in press, more than 40 countries representing more than two thirds of earth's population were participating with more than 45,000 responses already gathered.