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Chinese Journal of Zoonoses ; 37(12):1108-1117, 2021.
Article in Chinese | GIM | ID: covidwho-1818313


Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been a global pandemic. Safe and effective vaccination is critical to ending the epidemic of COVID-19. Although randomized clinical trials are considered the "gold standard" for evaluating intervention effects of vaccines, they have notable limitations. As mass vaccination campaigns against COVID-19 commence worldwide, vaccine effectiveness needs to be assessed for a range of outcomes across diverse populations in a noncontrolled setting. Meanwhile, SARS-CoV-2 variants continue to emerge during the global pandemic and may facilitate escape from current vaccine immune protection. Hence, COVID19 vaccines faced many challenges, such as safety, immunogenicity, and efficacy of the COVID-19 Vaccine in special populations, the duration of protective effectiveness, viral mutations and breakthrough infection, antibody-dependent enhancement effect, and pathogenic autoimmune and so on. This article summarizes th.

Nonlinear Dyn ; 106(2): 1187-1195, 2021.
Article in English | MEDLINE | ID: covidwho-1182278


The extensive proliferation of recent coronavirus (COVID-19), all over the world, is the outcome of social interactions through massive transportation, gatherings and population growth. To disrupt the widespread of COVID-19, a mechanism for social distancing is indispensable. Also, to predict the effectiveness and quantity of social distancing for a particular social network, with a certain contagion, a generalized model is needed. In this manuscript, we propose a social distancing mediated generalized model to predict the pandemic spread of COVID-19. By considering growth rate as a temporal harmonic function damped with social distancing in generalized Richard model and by using the data of confirmed COVID-19 cases in China, USA and India, we find that, with time, the cumulative spread grows more rapidly due to weak social distancing as compared to the stronger social distancing, where it is explicitly decreasing. Furthermore, we predict the possible outcomes with various social distancing scenarios by considering highest growth rate as an initial state, and illustrate that the increase in social distancing tremendously decreases growth rate, even it tends to reach zero in lockdown regimes. Our findings not only provide epidemic growth scenarios as a function of social distancing but also provide a modified growth model to predict controlled information flow in any network.

Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 42(3): 376-382, 2020 Jun 30.
Article in Chinese | MEDLINE | ID: covidwho-631729


Objective To summarize the clinical characteristics and chest CT findings of coronavirus disease 2019(COVID-19)patients in Peking Union Medical College Hospital(PUMCH). Methods A total of 13 patients with COVID-19 confirmed at PUMCH from January 20 to February 6,2020 were selected as the research subjects.Their epidemiological histories,clinical characteristics,laboratory tests,and chest CT findings were analyzed retrospectively.The location,distribution,density,and other accompanying signs of abnormal lung CT lesions were recorded,and the clinical types of these patients were assessed. Results The clinical type was "common type" in all these 13 patients aged(46.8±14.7)years(range:27-68 years).Ten patients had a travel history to Wuhan or direct contact with patients from Wuhan,2 cases had recent travel histories,and 1 case had a travel history to Beijing suburb.The white blood cell(WBC)count was normal or decreased in 92.3% of the patients and the lymphocyte count decreased in 15.4% of the patients.Twelve patients(92.3%)had a fever,among whom 11 patients were admitted due to fever and 2 patients(15.4%)had low fever.Eight patients(61.5%)had dry cough.The CT findings in these 13 patients were all abnormal.The lesions were mainly distributed along the bronchi and under the pleura.The lesions were relatively limited in 8 patients(affecting 1-3 lobes,predominantly in the right or left lower lobe),and diffuse multiple lesions of bilateral lungs were seen in 5 patients.The CT findings mainly included ground glass opacities(GGOs)(n=10,76.9%),focal consolidation within GGOs(n=7,53.8%),thickened vascular bundle passing through the lesions(n=10,76.9%),bronchial wall thickening(n=12,92.3%),air bronchogram(n=10,76.9%),vacuole signs in the lesions(n=7,53.8%),fine reticulation and interlobular septal thickening(n=3,23.1%),reversed halo-sign(n=2,15.4%),crazy-paving pattern(n=2,15.4%),and pleural effusion(n=2,15.4%).Conclusions Most of our patients diagnosed with COVID-19 at PUMCH had a travel history to Wuhan or direct contact with patients from Wuhan.The first symptoms of COVID-19 mainly include fever and dry cough,along with normal or reduced counts of WBC and lymphocytes.CT may reveal that the lesions distribute along the bronchi and under the pleura;they are typically localized GGOs in the early stage but can become multiple GGOs and infiltrative consolidation in both lungs in the advanced stage.Scattered vacuole signs may be visible inside the lesions in some patients.

Betacoronavirus , Coronavirus Infections , Pandemics , Pneumonia, Viral , Adult , Aged , COVID-19 , Coronavirus Infections/diagnostic imaging , Humans , Lung , Middle Aged , Pneumonia, Viral/diagnostic imaging , Retrospective Studies , SARS-CoV-2 , Tomography, X-Ray Computed