scholarly journals Estimating the Number of Infected by COVID-19 in Italy

2020 ◽  
Author(s):  
Pedro H.P. Cintra ◽  
Felipe N. Fontinele
Keyword(s):  
Herd Immunity ◽  
Rate Of Change ◽  
The Novel ◽  
Seir Model ◽  
The Real ◽  
Early Stages ◽  
Novel Coronavirus

Italy suffered heavily with the new pandemic crisis caused by the novel coronavirus SARS-CoV-2. Given the low number of tests performed on the early stages of the outbreak, Italy lost track of most of infections. We use a modified SEIR model to reconstruct the most realistic infection curve using the hospitalization curve of the registered data. Using this method we estimated that, by the end of the first infection wave, about 3-4% of the population will have been infected by the virus. Following the same process, the number of deaths is projected to be between 100000 to 115000. We also find a significant correlation between the number of tests performed, the fraction of undocumented infections and the rate of change dI/dt of the real infection curve. We conclude that herd immunity is not enough to contain further spread of the disease inside the country.

scholarly journals Analysis of the COVID-19 epidemic in french overseas department Mayotte based on a modified deterministic and stochastic SEIR model

2020 ◽  
Author(s):  
Solym Mawaki Manou-Abi ◽  
Julien Balicchi
Keyword(s):  
Transmission Rate ◽  
Control Measure ◽  
Exponential Growth Phase ◽  
The Novel ◽  
Rate Parameter ◽  
Seir Model ◽  
Stochastic Epidemic ◽  
Access To Water ◽  
Novel Coronavirus ◽  
Death Cases

AbstractIn order to anticipate a future trends in the development of the novel coronavirus COVID-19 epidemic started early at march 13, in the french overseas department Mayotte, we consider in this paper a modified deterministic and stochastic epidemic model. The model divides the total population into several possible states or compartment: susceptible (S), exposed (E) infected and being under an incubation period, infected (I) being infectious, simple or mild removed RM, severe removed (including hospitalized) RS and death cases (D). The adding of the two new compartment RM and RS are driven by data which together replace the original R compartment in the classical SEIR model.We first fit the constant transmission rate parameter to the epidemic data in Mayotte during an early exponential growth phase using an algorithm with a package of the software R and based on a Maximum Likewood estimator. This allows us to predict the epidemic without any control in order to understand how the control measure and public policies designed are having the desired impact of controlling the epidemic. To do this, we introduce a temporally varying decreasing transmission rate parameter with a control or quarantine parameter q. Then we pointed out some values of q to maintain control which is critical in Mayotte given the fragility of its health infrastructure and the significant fraction of the population without access to water.

scholarly journals Assessment of Anti-SARS CoV-2 seroprevalence in habitants of Assam (AASSHA): report of the first serosurvey in Assam

2021 ◽  
Vol 8 (5) ◽  
pp. 2490
Author(s):  
Jyotismita Pathak ◽  
Mridusmita Das ◽  
Khalil Siddique
Keyword(s):  
Public Health ◽  
Severe Acute Respiratory Syndrome ◽  
Herd Immunity ◽  
Health Policies ◽  
The Novel ◽  
Blood Samples ◽  
Public Health Policies ◽  
Novel Coronavirus

Background: Today, there is a pressing need to identify the proportion of people immune to the infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) so that public health policies can be formulated accordingly for the ongoing COVID-19 pandemic. Keeping this in mind, we designed a serosurvey in Assam with aims to estimate the prevalence of infection as well as the infection to case ratio of the novel coronavirus in Assam.Methods: A total of 9 districts belonging to three different strata of districts were randomly selected for the study. In these selected districts, blood samples were collected from a sample of population and were checked for the antibodies (IgG type). Those testing reactive for the mentioned antibodies were considered to have been infected ever before the onset of the study.Results: A total of 2390 study subjects were tested for the presence of antibodies against the SARS-CoV-2. The proportion of people harboring antibodies against the infection was found to be 23.7 percent.Conclusions: The serosurvey revealed that the proportion of people having antibodies was lower than that required for attaining herd immunity levels in a population. The case to infection ratios reveal that there is a large chunk of population who didn’t know about their infection.

scholarly journals Impact of Vaccination on the COVID-19 Pandemic: Evidence from U.S. States

2021 ◽  
Author(s):  
Xiao Chen ◽  
Hanwei Huang ◽  
Jiandong Ju ◽  
Ruoyan Sun ◽  
Jialiang Zhang
Keyword(s):  
Herd Immunity ◽  
Sir Model ◽  
Health Policies ◽  
Vaccine Hesitancy ◽  
The Novel ◽  
Vaccination Programs ◽  
Public Health Policies ◽  
Percentage Points ◽  
Novel Coronavirus ◽  
The U.S

Abstract Governments worldwide are implementing mass vaccination programs in an effort to end the novel coronavirus (COVID-19) pandemic. Here, we evaluated the effectiveness of the COVID-19 vaccination program and predicted the path to herd immunity in the U.S. We estimated that vaccination reduced the total number of new cases by 4.4 million (from 33.0 to 28.6 million), prevented approximately 0.12 million hospitalizations (from 0.89 to 0.78 million), and decreased the population infection rate by 1.34 percentage points (from 10.10–8.76%). We built a Susceptible-Infected-Recovered (SIR) model with vaccination to predict herd immunity. Our model predicts that the U.S. can achieve herd immunity by the last week of July 2021, with a cumulative vaccination coverage of 60.2%. Herd immunity could be achieved earlier with a faster vaccination pace, lower vaccine hesitancy, and higher vaccine effectiveness. These findings improve our understanding of the COVID-19 vaccination and can inform future public health policies.

scholarly journals Prevalence of Anti-SARS-CoV-2 Antibodies in Poznań, Poland, after the First Wave of the COVID-19 Pandemic

Vaccines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 541
Author(s):  
Dagny Lorent ◽  
Rafal Nowak ◽  
Carolina Roxo ◽  
Elzbieta Lenartowicz ◽  
Aleksandra Makarewicz ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Direct Contact ◽  
Herd Immunity ◽  
European Countries ◽  
Third Wave ◽  
The Novel ◽  
Igg Antibodies ◽  
Novel Coronavirus

In comparison to other European countries, during the first months of the COVID-19 pandemic, Poland reported a relatively low number of confirmed cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. To estimate the scale of the pandemic in Poland, a serosurvey of antibodies against SARS-CoV-2 was performed after the first wave of COVID-19 in Europe (March–May 2020). Within this study, we collected samples from 28 July to 24 September 2020 and, based on the ELISA results, we found that 1.67% (25/1500, 95% CI 1.13–2.45) of the Poznan (Poland) metropolitan area’s population had antibodies against SARS-CoV-2 after the first wave of COVID-19. However, the presence of anti-SARS-CoV-2 IgG antibodies was confirmed with immunoblotting in 56% (14/25) samples, which finally resulted in a decrease in seroprevalence, i.e., 0.93% (14/1500, 95% CI 0.56–1.56). The positive anti-SARS-CoV-2 IgG results were associated with age, occupation involving constant contact with people, travelling abroad, non-compliance with epidemiological recommendations and direct contact with the novel coronavirus. Our findings confirm the low SARS-CoV-2 incidence in Poland and imply that the population had little herd immunity heading into the second and third wave of the pandemic, and therefore, that herd immunity contributed little to preventing the high numbers of SARS-CoV-2 infections and COVID-19-related deaths in Poland during these subsequent waves.

scholarly journals Towards psychological herd immunity: Cross-cultural evidence for two prebunking interventions against COVID-19 misinformation

2021 ◽  
Vol 8 (1) ◽  
pp. 205395172110138
Author(s):  
Melisa Basol ◽  
Jon Roozenbeek ◽  
Manon Berriche ◽  
Fatih Uenal ◽  
William P. McClanahan ◽  
...  
Keyword(s):  
Real World ◽  
Herd Immunity ◽  
Cross Cultural ◽  
Effect Sizes ◽  
The Novel ◽  
Fake News ◽  
Societal Challenge ◽  
Novel Coronavirus

Misinformation about the novel coronavirus (COVID-19) is a pressing societal challenge. Across two studies, one preregistered ( n1 = 1771 and n2 = 1777), we assess the efficacy of two ‘prebunking’ interventions aimed at improving people’s ability to spot manipulation techniques commonly used in COVID-19 misinformation across three different languages (English, French and German). We find that Go Viral!, a novel five-minute browser game, (a) increases the perceived manipulativeness of misinformation about COVID-19, (b) improves people’s attitudinal certainty (confidence) in their ability to spot misinformation and (c) reduces self-reported willingness to share misinformation with others. The first two effects remain significant for at least one week after gameplay. We also find that reading real-world infographics from UNESCO improves people’s ability and confidence in spotting COVID-19 misinformation (albeit with descriptively smaller effect sizes than the game). Limitations and implications for fake news interventions are discussed.

scholarly journals Invincibility threatens vaccination intentions during a pandemic

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258432
Author(s):  
James M. Leonhardt ◽  
Garret Ridinger ◽  
Yu Rong ◽  
Amir Talaei-Khoe
Keyword(s):  
Risk Assessment ◽  
Health Behavior ◽  
Herd Immunity ◽  
Cultural Factors ◽  
The Novel ◽  
Personal Risk ◽  
Preventative Health ◽  
Multi Level ◽  
Novel Coronavirus ◽  
Level Analysis

Some people feel they are invincible to the novel coronavirus SARS-CoV-2 (COVID-19). They believe that being infected with COVID-19 would not be a serious threat to their health. While these people may or may not be correct in their personal risk assessment, we find that such perceived invincibility may undermine community efforts to achieve herd immunity. Multi-level analysis of survey respondents across 51 countries finds that perceived invincibility from COVID-19 is negatively associated with believing there is a need to prevent the spread of COVID-19 in one’s community (n = 218,956) and one’s willingness to inoculate against the disease (n = 71,148). These effects are most pronounced among individuals from countries lower in cultural collectivism (e.g., USA, UK, Canada) and highlight the need to consider the interplay of individual and cultural factors in our efforts to understand, predict, and promote preventative health behavior during a pandemic.

scholarly journals COVID-19 in Moscow: prognoses and scenarios

2020 ◽  
Vol 13 (1) ◽  
pp. 43-51 ◽  
Author(s):  
M. V. Tamm
Keyword(s):  
Critically Ill ◽  
Critically Ill Patients ◽  
Herd Immunity ◽  
Control Measures ◽  
Published Data ◽  
The Novel ◽  
Epidemic Control ◽  
Slow Development ◽  
Medium Level ◽  
Novel Coronavirus

Aim: to present a mathematical model of the development of COVID-19 in Moscow along with the analysis of some scenarios of epidemic control and possible epidemic consequences.Materials and Methods. The modeling of the epidemics was based on the extended SEIR model proposed lately in the group of Prof. R. Neher and realized as a freely available software program. The authors based the choice of the parameters of modeling on published data on the epidemiological properties of the novel coronavirus SARS-CoV-2 and open access data on the registered cases of COVID-19 in Moscow for 8-27 March 2020.Results. Five potential scenarios of the development of COVID-19 epidemics are studied. The scenarios are differed by the levels of the control measures: Null Scenario corresponded to the lack of protective measures, Scenario A – mild measures of the epidemic control (closing of schools and universities, recommendations for senior citizens to stay inside), Scenario B – medium level of control (closing of all public places, recommendation for the citizens to stay inside), Scenarios C and D – complete lockdown (from the beginning of May 2020 within Scenario C and from the beginning of April 2020 within Scenario D). It was shown that within the Null Scenario, the lethality from the novel coronavirus in Moscow will exceed 100 thousand people, and the number of critically ill patients on the peak of the epidemics will exceed the capacities of the system of healthcare. Scenarios A and B did not provide for a radical decrease in the fatality rate, and the number of critically ill patients at the peak of epidemics will still exceed the capacities of the system of healthcare. Besides, within Scenario B, the epidemics will last for more than a year. Scenarios C and D will allow for the control of epidemics and a significant decrease in the rate of letha lity (by 30 and 400 times, respectively). At the same time, these two scenarios prevent the population from developing herd immunity, which would result in the population susceptibility to repeated epidemics outbreaks. Conclusion. The scenarios intended for the slow development of herd immunity in the conditions of epidemic control would not bring sufficient results: the lethality would remain unacceptably high, the capacities of the system of healthcare would be overloaded, and the time of limiting measures would be unacceptably long. Such measures as complete lockdown would stop the present epidemics. The earlier they are introduced, the more efficient will be the results. To prevent further repeated outbreaks of the epidemics, it is necessary to establish a system of available, quick, and efficient testing in combination with point isolation of the infected patients and their contacts. 

scholarly journals COVID-19 denial in Turkmenistan veiling the real situation

2022 ◽  
Vol 80 (1) ◽  
Author(s):  
Hashim Talib Hashim ◽  
Ahed El Abed El Rassoul ◽  
John Bchara ◽  
Attaullah Ahmadi ◽  
Don Eliseo Lucero-Prisno
Keyword(s):  
Human Life ◽  
The Novel ◽  
Real Situation ◽  
The Real ◽  
The Public ◽  
Unethical Practices ◽  
First Case ◽  
Media Reports ◽  
The Government ◽  
Novel Coronavirus

AbstractCoronavirus disease 2019 (COVID-19) emerged in late 2019, with the first case identified in Wuhan City, Hubei Province, China, on 12 December 2019. In order to perceive the comprehensive impact of this pandemic, we have to know that misinformation and denials about COVID-19 have surely exacerbated its diffusion and hindered the response against it. Turkmenistan remains one of the very few countries in the world that lacks reports about emerging cases of the novel coronavirus. Turkmen authorities claim that they have adopted all attainable measures required in order to combat the virus, asserting that COVID-19 has yet to reach their country. Despite the government’s reported absence of COVID-19 in the country, rumors, media reports and independent sources suggest the spread of the pandemic in Turkmenistan. By mid-June 2020, the outbreak was referred to as being serious with patients suffering extreme health risks, and following its state of disrepair and unethical practices, many of those anticipated to be COVID-19 infected tend to suffer at home, discouraging any interaction with the healthcare system. The civil society in Turkmenistan, for the time being, takes full part of the government’s duty in the process of informing and educating the public regarding the COVID-19 pandemic, and endeavors to keep the government and WHO accountable for behaving in such repressive ways that could lead to rather preventable loss of human life in Turkmenistan. Yet, efforts hang fire before unveiling the real situation, and Turkmenistan’s government owning up to the negations and roaming speculations, not only regarding the coronavirus crisis, but every public-related issue itself.

scholarly journals Application of a generalized SEIR model for covid-19 in Algeria

2020 ◽  
Author(s):  
Mohamed LOUNIS ◽  
Juarez dos Santos AZEVEDO
Keyword(s):  
Model Prediction ◽  
Initial Evaluation ◽  
The Novel ◽  
Future Period ◽  
Seir Model ◽  
The World ◽  
Novel Coronavirus ◽  
Reported Data

The novel coronavirus diseases 2019 (COVID-19) in Wuhan is continuing to impress the world by its fast spread and the number of affected persons attracting an unprecedented attention. In this article, we used the classical SEIR model and a generalized SEIR model called SEIRDP model inspired in a model previously used during the outbreak in China to predict the evolution of COVID-19 in Algeria for a future period of 100 days using official reported data from early April to early August, 2020. Initial evaluation showed that the two models had a net correspondence with the reported data during this period for cumulative infected cases but the number of cumulative deaths was underestimated with the classical SEIR model. Model prediction with the SEIRDP concluded that the number of cumulative infected cases will increase in the next days reaching a number of about 60 k in middle November with a median of about 300 daily cases. Also, the number of estimated deaths will be around 2k. These results suggest that the COVID-19 is ongoing to infect more persons which may push national authorities to carefully act in the probable leaving of containment.

scholarly journals What Happens to the Immune System after Vaccination or Recovery from COVID-19?

Life ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1152
Author(s):  
Bruna T. Tiyo ◽  
Gabriela J. H. Schmitz ◽  
Marina M. Ortega ◽  
Laís T. da Silva ◽  
Alexandre de Almeida ◽  
...  
Keyword(s):  
Immune System ◽  
Herd Immunity ◽  
The Novel ◽  
Human Immune System ◽  
Disease Treatment ◽  
Leading Role ◽  
Virus Exposure ◽  
Review Reports ◽  
Novel Coronavirus

Due to its leading role in fighting infections, the human immune system has been the focus of many studies in the context of Coronavirus disease 2019 (COVID-19). In a worldwide effort, the scientific community has transitioned from reporting about the effects of the novel coronavirus on the human body in the early days of the pandemic to exploring the body’s many immunopathological and immunoprotecting properties that have improved disease treatment and enabled the development of vaccines. The aim of this review is to explain what happens to the immune system after recovery from COVID-19 and/or vaccination against SARS-CoV-2, the virus that causes the disease. We detail the way in which the immune system responds to a SARS-CoV-2 infection, including innate and adaptive measures. Then, we describe the role of vaccination, the main types of COVID-19 vaccines and how they protect us. Further, we explain the reason why immunity after COVID-19 infection plus a vaccination appears to induce a stronger response compared with virus exposure alone. Additionally, this review reports some correlates of protection from SARS-CoV-2 infection. In conclusion, we reinforce that vaccination is safe and important in achieving herd immunity.

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