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Detecting out-of-context media, such as "miscaptioned" images on Twitter, is a relevant problem, especially in domains of high public significance. In this work we aim to develop defenses against such misinformation for the topics of Climate Change, COVID-19, and Military Vehicles. We first present a large-scale multimodal dataset with over 884k tweets relevant to these topics. Next, we propose a detection method, based on the state-of-the-art CLIP model, that leverages automatically generated hard image-text mismatches. While this approach works well on our automatically constructed out-of-context tweets, we aim to validate its usefulness on data representative of the real world. Thus, we test it on a set of human-generated fakes created by mimicking in-thewild misinformation. We achieve an 11% detection improvement in a high precision regime over a strong baseline. Finally, we share insights about our best model design and analyze the challenges of this emerging threat.
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This paper introduces a bi-virus model with time-varying susceptibility. The model describes the case that there coexist two viruses and the time-varying susceptibility due to repeated infections. For different parameters, we investigate the stability of various equilibriums. Under appropriate conditions the two viruses show competitive relationship, that is, one virus will eventually become a pandemic, and the other virus will eventually disappear. For this case, we further study the dynamical behavior of virus transmission. The model shows some new phenomena, that is, the outbreak of the virus will be delayed appropriately, giving people an illusion. Finally, we present a numerical example to illustrate the effectiveness of the theoretical results. (c) 2022 Elsevier Ltd. All rights reserved.
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Background: China implemented strict lockdowns to contain COVID-19 at the early stage. We aimed to evaluate the impact of COVID-19 on HIV care continuum in China. Methods: Anonymized programmatic data on HIV care continuum between 1 January 2017 and 31 December 2020 were collected from seven provincial and municipal centers for disease control and prevention and eight major infectious disease hospitals specialized in HIV care in various regions in China. We performed interrupted time series analysis to characterize temporal trend in monthly numbers of HIV tests, HIV diagnosis, HIV antiretroviral therapy (ART) initiations, ART collections, and HIV post-exposure prophylaxis (PEP) prescriptions before, during and after the national lockdown period (23 January to 7 April 2020). We used Poisson segmented regression models to estimate the immediate impact of the lockdown on these outcomes, as well as post-lockdown trends. Results: During the study period, we recorded 1,101,686 HIV tests, 69,659 HIV diagnoses, 63,458 ART initiations, 1,593,490 ART collections, and 16,780 PEP prescriptions. A median of 789 (IQR 367-975), 409 (278-626), and 1045 (524-1262) HIV tests per day were recorded before, during and after lockdown. Lockdown was associated with 32.8% decrease in HIV testing in January 2020, the first month after lockdown (incidence rate ratio [IRR] 0.672;95% confidence interval [CI] 0.585-0.772). Daily HIV diagnoses decreased from a median of 50 (7-76) before lockdown, to 23 (6-46) during lockdown, and back to 48 (12-74) after lockdown, with an estimated 27.1% decrease in January 2020 (0.729, 0.599-0.887). There was no marked change in the number of ART initiation and ART collection during the lockdown, but the number of ART collection was lower than the expected level by the end of December 2020 (0.761, 0.659-0.879). The number of monthly PEP prescriptions decreased significantly during the lockdown (0.362, 0.220-0.595) and still had not recovered to the expected level by the end of December 2020 (0.456, 0.362-0.574). With the ease of restrictions, HIV testing (slope change 1.067/month, 1.048-1.086) and PEP prescriptions (1.077/month, 1.016-1.142) showed a significant increasing trend. Conclusion: ART initiation and ART collection generally remained stable during the lockdown, but HIV testing, HIV diagnosis and PEP prescription were affected. ART collection and PEP prescriptions have not recovered to expected levels in the eighth month after the suspension of lockdown.
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Since the outbreak of COVID-19, countries around the world have shown different time-series characteristics. Studying the characteristics of the development patterns of different countries and revealing the dominant factors behind them can provide references for future prevention and control strategies. In order to reveal the similarities and differences between the epidemic time series in different countries, this article extracts the standard deviation, Hurst index, cure rate, growth time, average growth rate, and prevention and control efficiency of the daily time series of new cases in the main epidemic countries for pedigree clustering. We also analyzes the causes of clustering results from the aspects of economics, medical treatment, and humanistic conflicts. The results show that the global epidemic development model can be divided into three categories: C-type, S-type, and I-type. The time series of C-type countries are characterized by continuous fluctuations and rising, and the cure rate is low. The reason is that humanistic conflicts are not conducive to epidemic prevention and control. Economic and medical resources have become scarce after a long period of large consumption. It is recommended to strengthen publicity and guidance in prevention and control, change concepts, and coordinate the allocation of economic and medical resources. The time series of S-type countries is characterized by a rapid rise and then an immediate decline, and eventually maintains a stable trend. The overall cure rate is relatively high. The reason is that these countries have domestic stability, high economic and medical standards, and timely prevention and control measures. It is recommended to strengthen international cooperation and scientific research, and prepare for the possible second epidemic. The time series of I-shaped countries is characterized by a slow rise, the overall development trend is unstable, and the cure rate is low. The reason is that its outbreak is relatively late and less severe. Most of the economic and medical levels and humanistic conflicts are not conducive to epidemic prevention and control. It is recommended to learn better prevention and control experience, implement strict isolation measures, try to meet the material needs during the epidemic, and optimize treatment methods. 2021, Science Press. All right reserved.
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As the main utilities for responding to public health emergencies such as "SARS" and "COVID-19", the spatial distribution of hospitals directly affects the speed of prevention and control of such emergencies. This research aims to analyze the spatial geographic distribution characteristics of Chinese hospitals. Using GIS, SPSS and other analytical tools, the characteristics of spatial distribution of hospitals and their influencing factors are analyzed from the perspective of macroscopic pattern and provincial layout. The results show that: (1) From 2001 to 2016, China's hospital construction forms two belt type growth structures led respectively by the central and western regions and the eastern coastal regions, which showed an overall growth trend with "high in the East, low in the middle and high in the West, and slow growth in the Far West and northeast regions;The provincial capital cities show obvious growth characteristics of "Regionalization". (2) The distribution of China's high-quality hospitals show a strong spatial structure in the East, and weak in the West, and the hospitals in the central and western regions show the characteristics of numerous but not refined, large but not strong;The core density of hospitals gradually moves to the east of China together with the increase of hospital level, the top three hospitals also form a single core structure, and the cluster phenomenon is clear. (3) The distribution of Chinese hospitals exhibit four agglomeration characteristics: single center agglomeration, axis agglomeration of high location quotient value, band agglomeration of middle location quotient value and cluster agglomeration of low location quotient value. (4) Through the analysis, it is found that the registered population at each year, built-up area, fixed asset investment and the total retail sales of social consumer goods in the city have a positive impact on the distribution of medical resources. © 2021, Zhejiang University Press. All right reserved.
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This special issue contains 12 articles that describes the prevalence, incidence, epidemiology, and outbreak of the COVID-19 in China.
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Objective: To study the clinical application effect of modified nasopharyngeal swab sampling for 2019 novel coronavirus nucleic acid detection. Methods: This study covered the period from January 14 to March 1, 2020.The supine position method and the protective face screen were used to collect nasopharyngeal swabs from February 24 onwards, before which, the nasopharyngeal swabs were collected by sitting position method. All the patients who were diagnosed with suspected/confirmed 2019 novel coronavirus infection were admitted from February 19 with the nasopharyngeal swabs collected outside the hospital before admission. (1) Thirty-four swabbing operators meeting the inclusion criteria of the study were recruited in this retrospective cohort study. They were grouped according to the collection method of nasopharyngeal swabs. Sixteen operators of Wuhan Taikang Tongji Hospital who applied the supine position method and the protective face screen were included in supine position method+ protective face screen group (15 males and 1 female, aged 34-49 years); 18 operators (12 from the First Affiliated Hospital of Army Medical University (the Third Military Medical University), 1 from Wuhan Jiangxia Mobile Cabin Hospital, 5 from the East District of People's Hospital of Wuhan University) who applied the traditional sitting position method were included in sitting position method group (2 males and 16 females, aged 25-49 years). In supine position method+ protective face screen group, when collecting sample, the patient lay flat and wore a special protective face screen for nasopharyngeal swab sampling, with neck slightly extending and face turning to the opposite side of the operator about 10°. The self-designed questionnaire was used to investigate the cooperation, the incidence of nausea, coughing, sneezing, and struggling of patients evaluated by the operators, the operation time for a single swab sample, the fear of operation and the perceived exposure risk of operators in the two groups. (2) Sixty-five patients (22 males and 43 females, aged 25-91 years) admitted to Wuhan Taikang Tongji Hospital who successively received the sitting position method and supine position method+ protective face screen for nasopharyngeal swabs sampling and with complete nucleic acid detection results were included. The positive rates of nucleic acid detection by the two sampling methods of nasopharyngeal swabs of the patients were statistically analyzed. (3) Forty-one patients who could express their feelings accurately were selected out of those 65 patients (12 males and 29 females, aged 27-83 years). The comfort of patients in the process of sampling by the two methods was investigated. (4) Thirty-four patients (10 males and 24 females, aged 25-83 years) with two or more consecutive negative results of nucleic acid detection of nasopharyngeal swabs by sitting position method were selected from the above 65 patients. The positive rate of nucleic acid detection of nasopharyngeal swab of patients by supine position method+ protective face screen, i. e. negative to positive rate was statistically analyzed. Data were statistically analyzed with t test, Wilcoxon signed rank test, and chi-square test. Results: (1) Compared with those of sitting position method group, the cooperation score of patients evaluated by the operators in supine position method+ protective face screen group was significantly higher (Z=-4.928, P<0.01), the incidence of nausea, choking cough, sneezing, and struggling of patients evaluated by the operators, and the fear of operation score and the perceived exposure risk score of operators in supine position method+ protective face screen group were significantly lower (Z=-5.071, -5.046, -4.095, -4.397, -4.174, -5.049, P<0.01), and the operation time for a single swab sample in supine position method+ protective face screen group was significantly longer (t=223.17, P<0.01). (2) The positive rate of nucleic acid detection of nasopharyngeal swabs by supine position method+ protective face screen was 60.00% (39/65), which was obviously higher than 41.54% (27/65) by sitting position method (χ(2)=4.432, P<0.05). (3) The comfort score of the 41 patients during nasopharyngeal swabs sampling by supine position method+ protective face screen was significantly higher than that by sitting position method (Z=-5.319, P<0.01). (4) Of the 34 patients with two or more consecutive negative results of nucleic acid detection of nasopharyngeal swabs by sitting position method, the rate of negative to positive of nucleic acid detection was 26.47% (9/34) after sampling by supine position method+ protective face screen. Conclusions: Compared with the traditional sitting position method, detection of 2019 novel coronavirus nucleic acids of nasopharyngeal swabs collected by supine method combined with protective face screen is worth promoting, because of its better comfort of patients, low exposure risk for operators, in addition to reducing in the false negative result to some extent, which may help reduce false recurrence of discharged patients.
Subject(s)
Betacoronavirus , Coronavirus Infections , Pandemics , Pneumonia, Viral , Adult , Aged , Aged, 80 and over , COVID-19 , Female , Humans , Male , Middle Aged , Nucleic Acids , Retrospective Studies , SARS-CoV-2ABSTRACT
Coronavirus disease 2019 (COVID-19) outbroke in Wuhan, China in December 2019 and the severe acute respiratory syndrome (SARS) outbroke in Guangzhou, China in 2003 were caused by highly pathogenic coronaviruses with high homology. Since the 2019 novel coronavirus is highly contagious and spreads rapidly. It has caused negative social effects and massive economic loss globaly. Currently there is no vaccine or effective drugs. Pulmonary fibrosis is a pulmonary disease with progressive fibrosis, which is the main factor leading to pulmonary dysfunction and declined quality of life in SARS survivors after recovery. Extensive epidemiological, viral immunological and current clinical evidences support the possibility that pulmonary fibrosis may be one of the major complications in COVID-19 patients. At present there is no report on the mechanism by which COVID-19 induces pulmonary fibrosis.With the existing theoretical basis, this article focuses on discussing the possible mechanism of COVID-19 sustained lung damaging, the key role of abnormal immune mechanism in the initiation and promotion of pulmonary fibrosis, and the corresponding therapeutic measures.