scholarly journals Discrete SIR modelling using empirical infection data shows that SARS-CoV-2 infection provides short-term immunity

2020 ◽  
Author(s):  
Andrew McMahon ◽  
Nicole C. Robb
Keyword(s):  
Transmission Dynamics ◽  
Economic Damage ◽  
The Novel ◽  
Anecdotal Evidence ◽  
Serological Testing ◽  
Short Term ◽  
Testing Strategies ◽  
Global Pandemic ◽  
Subsequent Exposure ◽  
Novel Coronavirus

Background: The novel coronavirus SARS-CoV-2, which causes the COVID-19 disease, has resulted in a global pandemic. Since its emergence in December 2019, the virus has infected millions of people, caused the deaths of hundreds of thousands and resulted in incalculable social and economic damage. Understanding the infectivity and transmission dynamics of the virus is essential for understanding how best to reduce mortality whilst ensuring minimal social restrictions to the lives of the general population. Anecdotal evidence is available, but detailed studies have not yet revealed whether infection with the virus results in immunity. Objective: The objective of the study was to use mathematical modelling to investigate the reinfection frequency of COVID-19. Methods: We have used the SIR (Susceptible, Infected, Recovered) framework and random processing based on empirical SARS-CoV-2 infection and fatality data from different regions to calculate the number of reinfections that would be expected to occur if no immunity to the disease occurred. Results: Our model predicts that cases of reinfection should have been observed by now if primary SARS-CoV-2 infection did not protect from subsequent exposure in the short term, however, no such cases have been documented. Conclusions: This work concludes that infection with the SARS-CoV-2 virus provides short-term immunity to reinfection and therefore provides a useful insight for serological testing strategies, lockdown easing and vaccine design.

scholarly journals Reinfection with SARS-CoV-2: Discrete SIR (Susceptible, Infected, Recovered) Modeling Using Empirical Infection Data

10.2196/21168 ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. e21168
Author(s):  
Andrew McMahon ◽  
Nicole C Robb
Keyword(s):  
Vaccine Development ◽  
Transmission Dynamics ◽  
Economic Damage ◽  
The Novel ◽  
Serological Testing ◽  
Short Term ◽  
Testing Strategies ◽  
Global Pandemic ◽  
Subsequent Exposure ◽  
Novel Coronavirus

Background The novel coronavirus SARS-CoV-2, which causes the COVID-19 disease, has resulted in a global pandemic. Since its emergence in December 2019, the virus has infected millions of people, caused the deaths of hundreds of thousands, and resulted in incalculable social and economic damage. Understanding the infectivity and transmission dynamics of the virus is essential to determine how best to reduce mortality while ensuring minimal social restrictions on the lives of the general population. Anecdotal evidence is available, but detailed studies have not yet revealed whether infection with the virus results in immunity. Objective The objective of this study was to use mathematical modeling to investigate the reinfection frequency of COVID-19. Methods We have used the SIR (Susceptible, Infected, Recovered) framework and random processing based on empirical SARS-CoV-2 infection and fatality data from different regions to calculate the number of reinfections that would be expected to occur if no immunity to the disease occurred. Results Our model predicts that cases of reinfection should have been observed by now if primary SARS-CoV-2 infection did not protect individuals from subsequent exposure in the short term; however, no such cases have been documented. Conclusions This work concludes that infection with SARS-CoV-2 provides short-term immunity to reinfection and therefore offers useful insight for serological testing strategies, lockdown easing, and vaccine development.

Reinfection with SARS-CoV-2: Discrete SIR (Susceptible, Infected, Recovered) Modeling Using Empirical Infection Data (Preprint)

2020 ◽  
Author(s):  
Andrew McMahon ◽  
Nicole C Robb
Keyword(s):  
Vaccine Development ◽  
Transmission Dynamics ◽  
Economic Damage ◽  
The Novel ◽  
Serological Testing ◽  
Short Term ◽  
Testing Strategies ◽  
Global Pandemic ◽  
Subsequent Exposure ◽  
Novel Coronavirus

BACKGROUND The novel coronavirus SARS-CoV-2, which causes the COVID-19 disease, has resulted in a global pandemic. Since its emergence in December 2019, the virus has infected millions of people, caused the deaths of hundreds of thousands, and resulted in incalculable social and economic damage. Understanding the infectivity and transmission dynamics of the virus is essential to determine how best to reduce mortality while ensuring minimal social restrictions on the lives of the general population. Anecdotal evidence is available, but detailed studies have not yet revealed whether infection with the virus results in immunity. OBJECTIVE The objective of this study was to use mathematical modeling to investigate the reinfection frequency of COVID-19. METHODS We have used the SIR (Susceptible, Infected, Recovered) framework and random processing based on empirical SARS-CoV-2 infection and fatality data from different regions to calculate the number of reinfections that would be expected to occur if no immunity to the disease occurred. RESULTS Our model predicts that cases of reinfection should have been observed by now if primary SARS-CoV-2 infection did not protect individuals from subsequent exposure in the short term; however, no such cases have been documented. CONCLUSIONS This work concludes that infection with SARS-CoV-2 provides short-term immunity to reinfection and therefore offers useful insight for serological testing strategies, lockdown easing, and vaccine development.

scholarly journals Characterizing Two Outbreak Waves of COVID-19 in Spain Using Phenomenological Epidemic Modelling

2021 ◽  
Author(s):  
Miguel López ◽  
Alberto Peinado ◽  
Andrés Ortiz
Keyword(s):  
Growth Model ◽  
Logistic Growth ◽  
Data Series ◽  
The Novel ◽  
Short Term ◽  
Growth Trend ◽  
Global Pandemic ◽  
First Case ◽  
Logistic Growth Model ◽  
Novel Coronavirus

AbstractSince the first case reported of SARS-CoV-2 the end of December 2019 in China, the number of cases quickly climbed following an exponential growth trend, demonstrating that a global pandemic is possible. As of December 3, 2020, the total number of cases reported are around 65,527,000 contagions worldwide, and 1,524,000 deaths affecting 218 countries and territories. In this scenario, Spain is one of the countries that has suffered in a hard way, the ongoing epidemic caused by the novel coronavirus SARS-CoV-2, namely COVID-19 disease. In this paper, we present the utilization of phenomenological epidemic models to characterize the two first outbreak waves of COVID-19 in Spain. The study is driven using a two-step phenomenological epidemic approach. First, we use a simple generalized growth model to fit the main parameters at the early epidemic phase; later, we apply our previous finding over a logistic growth model to that characterize both waves completely. The results show that even in the absence of accurate data series, it is possible to characterize the curves of case incidence, and even construct short-term forecast in the near time horizon.

Synthetic and semi-synthetic drugs as promising therapeutic option for the treatment of COVID-19

2020 ◽  
Vol 20 ◽  
Author(s):  
Ekta Shirbhate ◽  
Preeti Patel ◽  
Vijay K Patel ◽  
Ravichandran Veerasamy ◽  
Prabodh C Sharma ◽  
...  
Keyword(s):  
Therapeutic Option ◽  
Antiviral Treatment ◽  
The Novel ◽  
Clinical Experiences ◽  
Synthetic Compounds ◽  
Synthetic Drugs ◽  
Global Pandemic ◽  
The World ◽  
Novel Coronavirus

: The novel coronavirus disease-19 (COVID-19), a global pandemic that emerged from Wuhan, China has today travelled all around the world, so far 216 countries or territories with 21,732,472 people infected and 770,866 deaths globally (as per WHO COVID-19 update dated August 18, 2020). Continuous efforts are being made to repurpose the existing drugs and develop vaccines for combating this infection. Despite, to date, no certified antiviral treatment or vaccine prevails. Although, few candidates have displayed their efficacy in in vitro studies and are being repurposed for COVID-19 treatment. This article summarizes synthetic and semi-synthetic compounds displaying potent activity in their clinical experiences or studies against COVID-19 and also focuses on mode of action of drugs being repositioned against COVID-19.

scholarly journals Modeling and Forecasting of COVID-19 Spreading by Delayed Stochastic Differential Equations

Axioms ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 18
Author(s):  
Marouane Mahrouf ◽  
Adnane Boukhouima ◽  
Houssine Zine ◽  
El Mehdi Lotfi ◽  
Delfim F. M. Torres ◽  
...  
Keyword(s):  
Real Data ◽  
Economic Damage ◽  
Population Parameter ◽  
The Novel ◽  
First Case ◽  
Epidemiological Trend ◽  
Modeling And Forecasting ◽  
Novel Coronavirus ◽  
Parameter Values ◽  
Stochastic Time

The novel coronavirus disease (COVID-19) pneumonia has posed a great threat to the world recent months by causing many deaths and enormous economic damage worldwide. The first case of COVID-19 in Morocco was reported on 2 March 2020, and the number of reported cases has increased day by day. In this work, we extend the well-known SIR compartmental model to deterministic and stochastic time-delayed models in order to predict the epidemiological trend of COVID-19 in Morocco and to assess the potential role of multiple preventive measures and strategies imposed by Moroccan authorities. The main features of the work include the well-posedness of the models and conditions under which the COVID-19 may become extinct or persist in the population. Parameter values have been estimated from real data and numerical simulations are presented for forecasting the COVID-19 spreading as well as verification of theoretical results.

FEATURES OF THE COURSE AND TACTICS OF MANAGING CHILDREN WITH KIDNEYS AND URINARY TRACT DISEASES DURING THE PANDEMIC OF NEW CORONAVIRUS INFECTION COVID-19

2021 ◽  
Vol 100 (4) ◽  
pp. 74-79
Author(s):  
I.M. Kagantsov ◽  
◽  
V.V. Sizonov ◽  
V.G. Svarich ◽  
K.P. Piskunov ◽  
...  
Keyword(s):  
Age Groups ◽  
Clinical Manifestations ◽  
Routine Care ◽  
The Novel ◽  
Urinary System ◽  
Death Rates ◽  
Global Pandemic ◽  
Coronavirus Infection ◽  
Novel Coronavirus ◽  
Significant Health

The novel coronavirus infection (SARS-CoV-2), which first appeared in Wuhan, China in December 2019, has been declared a global pandemic by WHO. COVID-19 affects people of all age groups. The disease in children is usually asymptomatic or mild compared to adults, and with a significantly lower death rates. Data on kidney damage in children with COVID-19, as well as the effect of coronavirus infection on the course of diseases of the genitourinary system, are limited, the risks of contracting a new coronavirus infection in children with significant health problems, including those with chronic kidney disease, remain uncertain. The pandemic has affected the activities of surgeons treating diseases of the urinary system in children. Since the prospects for the end of the pandemic are vague, it is necessary to formulate criteria for selecting patients who can and should be provided with routine care in the pandemic. The purpose of this review is to highlight the features of the clinical manifestations and treatment of children with COVID-19, occurring against the background of previous renal pathology or complicating its course.

scholarly journals Emergence of SARS-CoV-2 through recombination and strong purifying selection

2020 ◽  
Vol 6 (27) ◽  
pp. eabb9153 ◽  
Author(s):  
Xiaojun Li ◽  
Elena E. Giorgi ◽  
Manukumar Honnayakanahalli Marichannegowda ◽  
Brian Foley ◽  
Chuan Xiao ◽  
...  
Keyword(s):  
Host Species ◽  
Purifying Selection ◽  
New Drugs ◽  
Evolutionary Constraints ◽  
Binding Motif ◽  
The Novel ◽  
Global Pandemic ◽  
Show Evidence ◽  
Human Coronaviruses ◽  
Novel Coronavirus

COVID-19 has become a global pandemic caused by the novel coronavirus SARS-CoV-2. Understanding the origins of SARS-CoV-2 is critical for deterring future zoonosis, discovering new drugs, and developing a vaccine. We show evidence of strong purifying selection around the receptor binding motif (RBM) in the spike and other genes among bat, pangolin, and human coronaviruses, suggesting similar evolutionary constraints in different host species. We also demonstrate that SARS-CoV-2’s entire RBM was introduced through recombination with coronaviruses from pangolins, possibly a critical step in the evolution of SARS-CoV-2’s ability to infect humans. Similar purifying selection in different host species, together with frequent recombination among coronaviruses, suggests a common evolutionary mechanism that could lead to new emerging human coronaviruses.

scholarly journals Covid-19 and food security: Jeopardy management and posterity deliberations

2021 ◽  
Vol 10 (2) ◽  
pp. 01-05
Author(s):  
Augustine Owusu-Addo ◽  
Atianashie Miracle A ◽  
Chukwuma Chinaza Adaobi ◽  
Larissa Agbemelo-Tsomafo
Keyword(s):  
Food Processing ◽  
Respiratory Illness ◽  
The United States ◽  
The Novel ◽  
Food Handling ◽  
Global Pandemic ◽  
Food Borne ◽  
Novel Coronavirus ◽  
Food Borne Infections ◽  
Safety Guidelines

COVID-19, also known as the ‘novel coronavirus disease 2019’, is a respiratory illness and the causative pathogen is officially named as ‘SARS-CoV-2’. Infections with SARS-CoV-2 have now been amplified to a global pandemic – as of April 3, 2020, nearly 1,018,000 cases have been confirmed in more than 195 countries, including more than 300,000 cases within the United States. Public safety guidelines are followed worldwide to stop the spread of COVID-19 and stay healthy. Despite COVID-19 is a respiratory illness with mode of invasion through the respiratory tract, not the gastrointestinal tract, an average food consumer is anxious and concerned about the food safety. Could an individual catch the deadly contagious COVID-19 from groceries brought home from the supermarket – or from the next restaurant takeout order? This brief review elucidates the epidemiology and pathobiological mechanism(s) of SARS-CoV-2 and its implications in food-borne infections, transmission via food surfaces, food processing and food handling.

scholarly journals The Impact of Armed Conflict on the Epidemiological Situation of COVID-19 in Libya, Syria and Yemen

2021 ◽  
Vol 9 ◽  
Author(s):  
Mohamed A. Daw
Keyword(s):  
Armed Conflict ◽  
Early Stage ◽  
Armed Conflicts ◽  
Cumulative Number ◽  
The Novel ◽  
Global Pandemic ◽  
Large Numbers ◽  
Public Data ◽  
Novel Coronavirus ◽  
The Impact

Background: Since the Arab uprising in 2011, Libya, Syria and Yemen have gone through major internal armed conflicts. This resulted in large numbers of deaths, injuries, and population displacements, with collapse of the healthcare systems. Furthermore, the situation was complicated by the emergence of COVID-19 as a global pandemic, which made the populations of these countries struggle under unusual conditions to deal with both the pandemic and the ongoing wars. This study aimed to determine the impact of the armed conflicts on the epidemiology of the novel coronavirus (SARS-CoV-2) within these war-torn countries and highlight the strategies needed to combat the spread of the pandemic and its consequences.Methods: Official and public data concerning the dynamics of the armed conflicts and the spread of SARS-COV-2 in Libya, Syria and Yemen were collected from all available sources, starting from the emergence of COVID-19 in each country until the end of December 2020. Datasets were analyzed by a set of statistical techniques and the weekly resolved data were used to probe the link between the intensity levels of the conflict and the prevalence of COVID-19.Results: The data indicated that there was an increase in the intensity of the violence at an early stage from March to August 2020, when it approximately doubled in the three countries, particularly in Libya. During that period, few cases of COVID-19 were reported, ranging from 5 to 53 cases/day. From September to December 2020, a significant decline in the intensity of the armed conflicts was accompanied by steep upsurges in the rate of COVID-19 cases, which reached up to 500 cases/day. The accumulative cases vary from one country to another during the armed conflict. The highest cumulative number of cases were reported in Libya, Syria and Yemen.Conclusions: Our analysis demonstrates that the armed conflict provided an opportunity for SARS-CoV-2 to spread. The early weeks of the pandemic coincided with the most intense period of the armed conflicts, and few cases were officially reported. This indicates undercounting and hidden spread during the early stage of the pandemic. The pandemic then spread dramatically as the armed conflict declined, reaching its greatest spread by December 2020. Full-blown transmission of the COVID-19 pandemic in these countries is expected. Therefore, urgent national and international strategies should be implemented to combat the pandemic and its consequences.

Teledentistry Platforms for Orthodontics

2021 ◽  
Vol 45 (1) ◽  
pp. 48-53
Author(s):  
Jae Hyun Park ◽  
Leah Rogowski ◽  
Janet H Kim ◽  
Sumayah Al Shami ◽  
Scott E I Howell
Keyword(s):  
Orthodontic Treatment ◽  
Healthcare Providers ◽  
The Novel ◽  
Interpersonal Interactions ◽  
Global Pandemic ◽  
Novel Coronavirus

Technology has transformed almost every aspect of our lives. Smartphones enable patients to request, receive, and transmit information irrespective of the time and place. The global pandemic has forced healthcare providers to employ technology to aid in ‘flattening the curve. The Novel Coronavirus, which is responsible for COVID-19, is transmitted primarily through person-to-person contact but may also be spread through aerosol generating procedures, so many clinics have severely limited interpersonal interactions. The purpose of this article is to provide helpful information for those orthodontists considering some form of remote practice. Various HIPAA-compliant telecommunication or teledentistry systems that can be used for orthodontic treatment are introduced and discussed. Detailed information about each platform that can potentially be used for orthodontics is provided in Figure 1. The authors do not endorse any of the products listed and the included software is not all inclusive but instead is a glimpse into the options available.

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