scholarly journals Comparison of seroprevalence of SARS-CoV-2 infections with cumulative and imputed COVID-19 cases: Systematic review

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0248946
Author(s):  
Oyungerel Byambasuren ◽  
Claudia C. Dobler ◽  
Katy Bell ◽  
Diana Patricia Rojas ◽  
Justin Clark ◽  
...  
Keyword(s):  
Herd Immunity ◽  
Primary Objective ◽  
Cumulative Number ◽  
Active Infection ◽  
Testing Strategies ◽  
Iga Antibodies ◽  
Different Populations ◽  
Almost All ◽  
General Community ◽  
Time Point

Background Accurate seroprevalence estimates of SARS-CoV-2 in different populations could clarify the extent to which current testing strategies are identifying all active infection, and hence the true magnitude and spread of the infection. Our primary objective was to identify valid seroprevalence studies of SARS-CoV-2 infection and compare their estimates with the reported, and imputed, COVID-19 case rates within the same population at the same time point. Methods We searched PubMed, Embase, the Cochrane COVID-19 trials, and Europe-PMC for published studies and pre-prints that reported anti-SARS-CoV-2 IgG, IgM and/or IgA antibodies for serosurveys of the general community from 1 Jan to 12 Aug 2020. Results Of the 2199 studies identified, 170 were assessed for full text and 17 studies representing 15 regions and 118,297 subjects were includable. The seroprevalence proportions in 8 studies ranged between 1%-10%, with 5 studies under 1%, and 4 over 10%—from the notably hard-hit regions of Gangelt, Germany; Northwest Iran; Buenos Aires, Argentina; and Stockholm, Sweden. For seropositive cases who were not previously identified as COVID-19 cases, the majority had prior COVID-like symptoms. The estimated seroprevalences ranged from 0.56–717 times greater than the number of reported cumulative cases–half of the studies reported greater than 10 times more SARS-CoV-2 infections than the cumulative number of cases. Conclusions The findings show SARS-CoV-2 seroprevalence is well below “herd immunity” in all countries studied. The estimated number of infections, however, were much greater than the number of reported cases and deaths in almost all locations. The majority of seropositive people reported prior COVID-like symptoms, suggesting that undertesting of symptomatic people may be causing a substantial under-ascertainment of SARS-CoV-2 infections.

scholarly journals Comparison of seroprevalence of SARS-CoV-2 infections with cumulative and imputed COVID-19 cases: systematic review

2020 ◽  
Author(s):  
Oyungerel Byambasuren ◽  
Claudia C Dobler ◽  
Katy Bell ◽  
Diana Patricia Rojas ◽  
Justin Clark ◽  
...  
Keyword(s):  
Herd Immunity ◽  
Primary Objective ◽  
List Type ◽  
Cumulative Number ◽  
Systematic Assessment ◽  
Testing Strategies ◽  
Different Populations ◽  
Almost All ◽  
General Community ◽  
Time Point

BackgroundAccurate seroprevalence estimates of SARS-CoV-2 in different populations could clarify the extent to which current testing strategies are identifying all active infection, and hence the true magnitude and spread of the infection. Our primary objective was to identify valid seroprevalence studies of SARS-CoV-2 infection and compare their estimates with the reported and imputed COVID-19 case rates within the same population at the same time point.MethodsWe searched PubMed, Embase, the Cochrane COVID-19 trials, and Europe-PMC for published studies and pre-prints that reported anti-SARS-CoV-2 IgG, IgM and/or IgA antibodies for serosurveys of the general community from 1 Jan to 12 Aug 2020.ResultsOf the 2199 studies identified, 170 were assessed for full text and 17 studies representing 15 regions and 118,297 subjects were includable. The seroprevalence proportions in 8 studies ranged between 1%-10%, with 5 studies under 1%, and 4 over 10% - from the notably hard-hit regions of Gangelt, Germany; Northwest Iran; Buenos Aires, Argentina; and Stockholm, Sweden. For seropositive cases who were not previously identified as COVID-19 cases, the majority had prior COVID-like symptoms. The estimated seroprevalences ranged from 0.56-717 times greater than the number of reported cumulative cases – half of the studies reported greater than 10 times more SARS-CoV-2 infections than the cumulative number of cases.ConclusionsThe findings show SARS-CoV-2 seroprevalence is well below herd immunity in all countries studied. The estimated number of infections, however, were much greater than the number of reported cases and deaths in almost all locations. The majority of seropositive people reported prior COVID-like symptoms, suggesting that undertesting of symptomatic people may be causing a substantial under-ascertainment of SARS-CoV-2 infections.Key messagesSystematic assessment of 17-country data show SARS-CoV-2 seroprevalence is mostly less than 10% - levels well below “herd immunity”.High symptom rates in seropositive cases suggest undertesting of symptomatic people and could explain gaps between seroprevalence rates and reported cases.The estimated number of infections for majority of the studies ranged from 2-717 times greater than the number of reported cases in that region and up to 13 times greater than the cases imputed from number of reported deaths.

Modeling COVID-19 Growing Trends to Reveal the Differences in the Effectiveness of Non-Pharmaceutical Interventions among Countries in the World (Preprint)

2020 ◽  
Author(s):  
You Chen ◽  
Yubo Feng ◽  
Chao Yan ◽  
Xinmeng Zhang ◽  
Cheng Gao
Keyword(s):  
Secondary Analysis ◽  
Reproduction Rate ◽  
Cumulative Number ◽  
Linear Regression Models ◽  
Growth Data ◽  
Dynamic Changes ◽  
The World ◽  
Four Levels ◽  
Almost All ◽  
Pharmaceutical Interventions

BACKGROUND Adopting non-pharmaceutical interventions (NPIs) can affect COVID-19 growing trends, decrease the number of infected cases, and thus reduce mortality and healthcare demand. Almost all countries in the world have adopted non-pharmaceutical interventions (NPIs) to control the spread rate of COVID-19; however, it is unclear what are differences in the effectiveness of NPIs among these countries. OBJECTIVE We hypothesize that COVID-19 case growth data reveals the efficacy of NPIs. In this study, we conduct a secondary analysis of COVID-19 case growth data to compare the differences in the effectiveness of NPIs among 16 representative countries in the world. METHODS This study leverages publicly available data to learn patterns of dynamic changes in the reproduction rate for sixteen countries covering Asia, Europe, North America, South America, Australia, and Africa. Furthermore, we model the relationships between the cumulative number of cases and the dynamic reproduction rate to characterize the effectiveness of the NPIs. We learn four levels of NPIs according to their effects in the control of COVID-19 growth and categorize the 16 countries into the corresponding groups. RESULTS The dynamic changes of the reproduction rate are learned via linear regression models for all of the studied countries, with the average adjusted R-squared at 0.96 and the 95% confidence interval as [0.94 0.98]. China, South Korea, Argentina, and Australia are at the first level of NPIs, which are the most effective. Japan and Egypt are at the second level of NPIs, and Italy, Germany, France, Netherlands, and Spain, are at the third level. The US and UK have the most inefficient NPIs, and they are at the fourth level of NPIs. CONCLUSIONS COVID-19 case growth data provides evidence to demonstrate the effectiveness of the NPIs. Understanding the differences in the efficacy of the NPIs among countries in the world can give guidance for emergent public health events. CLINICALTRIAL NA

scholarly journals Modelling spreading of an infection using time series by a novel family of models; fitting the time series of the confirmed cases of COVID-19 in China

2020 ◽  
Vol 9 (s1) ◽  
Author(s):  
Babak Jamshidi ◽  
Shahriar Jamshidi Zargaran ◽  
Mansour Rezaei
Keyword(s):  
Infectious Disease ◽  
Time Series ◽  
Communicable Disease ◽  
Time Series Models ◽  
Cumulative Number ◽  
The Novel ◽  
New Family ◽  
Two Samples ◽  
Almost All ◽  
Number Of Individuals

AbstractIntroductionTime series models are one of the frequently used methods to describe the pattern of spreading an epidemic.MethodsWe presented a new family of time series models able to represent the cumulative number of individuals that contracted an infectious disease from the start to the end of the first wave of spreading. This family is flexible enough to model the propagation of almost all infectious diseases. After a general discussion on competent time series to model the outbreak of a communicable disease, we introduced the new family through one of its examples.ResultsWe estimated the parameters of two samples of the novel family to model the spreading of COVID-19 in China.DiscussionOur model does not work well when the decreasing trend of the rate of growth is absent because it is the main presumption of the model. In addition, since the information on the initial days is of the utmost importance for this model, one of the challenges about this model is modifying it to get qualified to model datasets that lack the information on the first days.

scholarly journals The Effect of Vaccination Rates on the Infection of COVID-19 under the Vaccination Rate below the Herd Immunity Threshold

2021 ◽  
Vol 18 (14) ◽  
pp. 7491
Author(s):  
Yi-Tui Chen
Keyword(s):  
Infection Rate ◽  
Herd Immunity ◽  
The United States ◽  
Vaccination Rate ◽  
Infection Rates ◽  
Vaccination Rates ◽  
The United Kingdom ◽  
The World ◽  
Almost All ◽  
The Impact

Although vaccination is carried out worldwide, the vaccination rate varies greatly. As of 24 May 2021, in some countries, the proportion of the population fully vaccinated against COVID-19 has exceeded 50%, but in many countries, this proportion is still very low, less than 1%. This article aims to explore the impact of vaccination on the spread of the COVID-19 pandemic. As the herd immunity of almost all countries in the world has not been reached, several countries were selected as sample cases by employing the following criteria: more than 60 vaccine doses per 100 people and a population of more than one million people. In the end, a total of eight countries/regions were selected, including Israel, the UAE, Chile, the United Kingdom, the United States, Hungary, and Qatar. The results find that vaccination has a major impact on reducing infection rates in all countries. However, the infection rate after vaccination showed two trends. One is an inverted U-shaped trend, and the other is an L-shaped trend. For those countries with an inverted U-shaped trend, the infection rate begins to decline when the vaccination rate reaches 1.46–50.91 doses per 100 people.

Effects of Population Structure and Admixture on Exact Tests for Association Between Loci

Genetics ◽  
2003 ◽  
Vol 164 (1) ◽  
pp. 381-387
Author(s):  
B Law ◽  
J S Buckleton ◽  
C M Triggs ◽  
B S Weir
Keyword(s):  
Population Subdivision ◽  
Data Sets ◽  
Multilocus Genotype ◽  
Test Statistic ◽  
Exact Test ◽  
Testing Strategies ◽  
Different Populations ◽  
Alternative Testing ◽  
Sparse Data Sets ◽  
Alternative Testing Strategies

Abstract The probability of multilocus genotype counts conditional on allelic counts and on allelic independence provides a test statistic for independence within and between loci. As the number of loci increases and each sampled genotype becomes unique, the conditional probability becomes a function of total heterozygosity. In that case, it does not address between-locus dependence directly but only indirectly through detection of the Wahlund effect. Moreover, the test will reject the hypothesis of allelic independence only for small values of heterozygosity. Low heterozygosity is expected for population subdivision but not for population admixture. The test may therefore be inappropriate for admixed populations. If individuals with parents in two different populations are always considered to belong to one of the populations, then heterozygosity is increased in that population and the exact test should not be used for sparse data sets from that population. If such a case is suspected, then alternative testing strategies are suggested.

Phase I study of mesothelin-targeted immunotoxin LMB-100 in combination with tofacitinib in patients with advanced pancreatobiliary cancer.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 3051-3051
Author(s):  
Nebojsa Skorupan ◽  
Mehwish Iqra Ahmad ◽  
Guillaume Joe Pegna ◽  
Cody J. Peer ◽  
Jane B. Trepel ◽  
...  
Keyword(s):  
Solid Tumors ◽  
Dose Level ◽  
Dose Escalation ◽  
Single Agent ◽  
Primary Objective ◽  
Pseudomonas Exotoxin A ◽  
Recombinant Immunotoxin ◽  
Level 1 ◽  
Expansion Cohort ◽  
Almost All

3051 Background: LMB-100 recombinant immunotoxin consists of a mesothelin-binding Fab for targeting a modified Pseudomonas exotoxin A payload to tumors. Previous clinical trials demonstrated that almost all patients formed anti-drug-antibodies (ADAs) to LMB-100 that made administration beyond cycle 2 ineffective. Tofacitinib is an oral JAK inhibitor that prevented formation of ADAs against a closely related immunotoxin in pre-clinical studies. The primary objective of the dose escalation cohort was assessment of safety and tolerability of LMB-100 given with tofacitinib to patients with mesothelin-expressing solid tumors. The primary objective of the expansion cohort was to determine whether co-administration of tofacitinib delays formation of neutralizing LMB-100 ADAs. Methods: Patients (n = 13) with pancreatic adenocarcinoma and other mesothelin-expressing solid tumors (n = 3; cholangiocarcinoma, appendix, cystadenocarcinoma) were treated for up to 3 cycles with LMB-100 as a 30-minute infusion on days 4, 6, and 8 at two dose levels (100 and 140 mcg/kg) and co-treated with oral tofacitinib for the first 10 days of the cycle (10 mg BID). Results: Dose level 1 of LMB-100 was started at 100 mcg/kg one dose level below the single agent MTD. Dose escalation to 140 mcg/kg (dose level 2) resulted in DLTs in 2 of the 3 patients treated: grade 3 cardiac toxicity and grade 4 hyponatremia, both attributed to capillary leak syndrome. Ultimately, 7 patients were treated at dose level 1 without DLTs and 100 mcg/kg was chosen as the LMB-100 dose for the expansion cohort. The last of 6 patients treated in the expansion cohort developed grade 4 pericardial effusion leading to early closure of the study for toxicity. No objective responses were seen. Of the 8 patients who received two cycles of treatment at MTD, 4 met prespecified criteria for ADA prevention, and 2 patients who went on to receive cycle 3 had detectable LMB-100 plasma drug levels after administration. Conclusions: LMB-100 was unable to be co-administered safely with tofacitinib. ADA formation was prevented in 2 patients through 3 cycles, a rare occurrence. Clinical trial information: NCT04034238.

scholarly journals STATISTICAL STUDIES ON PROTEIN POLYMORPHISM IN NATURAL POPULATIONS II. GENE DIFFERENTIATION BETWEEN POPULATIONS

Genetics ◽  
1978 ◽  
Vol 88 (2) ◽  
pp. 367-390
Author(s):  
Ranajit Chakraborty ◽  
Paul A Fuerst ◽  
Masatoshi Nei
Keyword(s):  
Genetic Differentiation ◽  
Natural Populations ◽  
Drift Theory ◽  
Alternative Hypotheses ◽  
Mean And Variance ◽  
Statistical Studies ◽  
Different Populations ◽  
Using Data ◽  
Almost All ◽  
Good Agreement

ABSTRACT With the aim of testing the validity of the mutation-drift hypothesis, we examined the pattern of genetic differentiation between populations by using data from Drosophila, fishes, reptiles, and mammals. The observed relationship between genetic identity and correlation of heterozygosities of different populations or species was generally in good agreement with the theoretical expectations from the mutation-drift theory, when the variation in mutation rate among loci was taken into account. In some species of Drosophila, however, the correlation was unduly high. The relationship between the mean and variance of genetic distance was also in good agreement with the theoretical prediction in almost all organisms. We noted that both the distribution of heterozygosity within species and the pattern of genetic differentiation between species can be explained by the same set of genetic parameters in each group of organisms. Alternative hypotheses for explaining these observations are discussed.

scholarly journals RBC Transfusion Triggers: Is There Anything New?

2020 ◽  
Vol 47 (5) ◽  
pp. 361-369
Author(s):  
Tina Tomic Mahecic ◽  
Martin Dünser ◽  
Jens Meier
Keyword(s):  
Clinical Practice ◽  
Adverse Effects ◽  
Scientific Evidence ◽  
Optimal Time ◽  
Blood Transfusions ◽  
Erythrocyte Concentrates ◽  
Optimal Time Point ◽  
Almost All ◽  
Rbc Transfusion ◽  
Time Point

For many years, in daily clinical practice, the traditional 10/30 rule (hemoglobin 10 g/dL – hematocrit 30%) has been the most commonly used trigger for blood transfusions. Over the years, this approach is believed to have contributed to a countless number of unnecessary transfusions and an unknown number of overtransfusion-related deaths. Recent studies have shown that lower hemoglobin levels can safely be accepted, even in critically ill patients. However, even these new transfusion thresholds are far beyond the theoretical limits of individual anemia tolerance. For this reason, almost all publications addressing the limits of acute anemia recommend physiological transfusion triggers to indicate the transfusion of erythrocyte concentrates as an alternative. Although this concept appears intuitive at first glance, no solid scientific evidence supports the safety and benefit of physiological transfusion triggers to indicate the optimal time point for transfusion of allogeneic blood. It is therefore imperative to continue searching for the most sensitive and specific parameters that can guide the clinician when to transfuse in order to avoid anemia-induced organ dysfunction while avoiding overtransfusion-related adverse effects. This narrative review discusses the concept of anemia tolerance and critically compares hemoglobin-based triggers with physiological transfusion for various clinical indications.

The need for preventive drugs and vaccines in global cancer control: a challenge for public health and for industry

2002 ◽  
Vol 18 (2) ◽  
pp. 84-90 ◽  
Author(s):  
Harri Vainio
Keyword(s):  
Animal Experiments ◽  
Cancer Control ◽  
Chemopreventive Agents ◽  
Long Run ◽  
Incidence And Mortality ◽  
The World ◽  
Order Of Magnitude ◽  
Different Populations ◽  
Almost All ◽  
Rich Countries

Ten million new cancer patients are diagnosed worldwide each year. There will be a dramatic increase over the next 20 years in the number of people contracting cancer, especially in the developing, poorer part of the world. Many types of cancer vary in incidence and mortality by more than an order of magnitude between different populations, and every type is rare in some part of the world, suggesting that cancers are in principle preventable. Many specific causes of cancer are known, from factors related to lifestyle, diet, infections and occupations. The remarkable advances in molecular understanding of the carcinogenesis process over the past 25 years have transformed the approaches in cancer control. About 15% of cancers worldwide are caused by known infectious agents. Human papillomavirus vaccines, which are already being tested, may, in the long run, be able to prevent almost all cervical cancers. New promising disciplines in prevention, such as chemoprevention, have emerged. Chemoprevention has been successfully achieved in numerous animal experiments, and has been validated in several clinical trials. But more effective and safer chemopreventive agents and vaccines are needed. Rising prices of medicines and vaccines are putting them beyond the reach of many people, even in rich countries. Future enhanced efforts on an international basis are needed to guarantee access to these lifesaving drugs and vaccines. Putting prevention high on the agenda requires political courage and a long-term perspective.

Spanish Revised Memory and Behavior Problems Checklist Scale (SpRMBPC): trans-cultural adaptation and validation of the RMBPC questionnaire

2011 ◽  
Vol 23 (7) ◽  
pp. 1160-1166 ◽  
Author(s):  
Mariela Gonzalez Salvia ◽  
Adriana Dawidowski ◽  
Marcelo Schapira ◽  
Silvana Figar ◽  
María Elvira Söderlund ◽  
...  
Keyword(s):  
Cultural Adaptation ◽  
Discriminant Validity ◽  
Psychiatric Morbidity ◽  
Disruptive Behaviors ◽  
Depression Symptoms ◽  
Spanish Speaking ◽  
Different Populations ◽  
Almost All ◽  
And Behavior ◽  
Anxiety Depression

ABSTRACTBackground: The use of standardized scales is critical for monitoring the interventions within and between different populations, but the current Spanish tools are dispersed in several scales. A simple tool for simultaneously and exhaustively evaluating patient's symptoms and caregiver's distress in Spanish-speaking groups is needed.Methods: RMBPC was translated into Spanish by cross-cultural adaptation. Comprehensibility and easiness of SpRMBPC were evaluated with 92 patient-caregiver dyads. Reliability, stability and scale structure were evaluated by Cronbach's α, test-retest and factor analysis respectively. Concurrent and discriminant validity were assessed by correlation with validated tools for measuring stage of dementia; memory, disruptive behaviors and depression symptoms of the patients; and anxiety, depression and burden of the caregivers (CDR, MMSE, NPIq, NPIdisruption, NPI depression, HADS-A; HADS-D and Zarit Burden Interview respectively).Results: Almost all caregivers completed the questionnaire (97% completeness; 7.5% missing data). Both the frequency of Patient's Symptoms and Caregiver Reaction scores and subscores displayed high stability and reliability. All of these scores correlated positively with their respective validated tools as predicted, except with MMSE. The patients' subscores for Disruptive Behaviors and Memory Impairment displayed their highest correlation with the disruptive symptoms and level of dementia validated tools.Conclusions: SpRMBPC is a validated tool for assessing the dementia stage and the psychiatric morbidity of patients and caregivers. The Frequency Disruption and Memory subscales assess specifically patient's disruptive symptoms and dementia stages. These tools can be applied to analyze the burden of the patient's disease and the caregiver's distress in Spanish-speaking populations.

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