COVID-19: asymptomatic carrier transmission is an underestimated problem

Zhao, Hongjun; Lu, Xiaoxiao; Deng, Yibin; Tang, Yue; Lü, Jiachun

doi:10.1017/s0950268820001235

Cited by 139 publications

(141 citation statements)

References 11 publications

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“…Many values were estimated to fit the beginning of expansion of disease in France, other were inferred from expert opinions, see Section 'Model parameters'. The proportion (1 − f ) ranges from 17.9% to 86% [1,[17][18][19][20] and some reviews therein [21]. The lower value was observed on board of the Diamond princess, i.e.…”

Section: Resultsmentioning

confidence: 99%

“…Value of parameter f: Recall that, (1 − f ) stands for the fraction of exposed individuals that becomes unreported infectious and corresponds to the proportion of asymptomatic or silent carriers or mild infectious. (1 − f ) ranges from 17.9% to 86% [1,[17][18][19][20] and some reviews therein [21]. The fractions of unreported individuals in these previous studies are derived from the number of tests performed.…”

Section: Model Parametersmentioning

confidence: 99%

“…demonstrated by [30] but not by all authors, see some reviews therein [21]. Note also that in the literature, the estimate of the mean duration of infectious period of reported individuals is not always clear, since some authors include hospitalisation or isolation period, others do not.…”

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confidence: 95%

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A model of COVID-19 transmission to understand the effectiveness of the containment measures: application to data from France

Zongo¹,

Zorom

Mophou

et al. 2020

Epidemiol. Infect.

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The main objective of this paper is to address the following question: are the containment measures imposed by most of the world governments effective and sufficient to stop the epidemic of COVID-19 beyond the lock-down period? In this paper, we propose a mathematical model which allows us to investigate and analyse this problem. We show by means of the reproductive number, R 0 that the containment measures appear to have slowed the growth of the outbreak. Nevertheless, these measures remain only effective as long as a very large fraction of population, p, greater than the critical value 1 − 1/R 0 remains confined. Using French current data, we give some simulation experiments with five scenarios including: (i) the validation of model with p estimated to 93%, (ii) the study of the effectiveness of containment measures, (iii) the study of the effectiveness of the large-scale testing, (iv) the study of the social distancing and wearing masks measures and (v) the study taking into account the combination of the large-scale test of detection of infected individuals and the social distancing with linear progressive easing of restrictions. The latter scenario was shown to be effective at overcoming the outbreak if the transmission rate decreases to 75% and the number of tests of detection is multiplied by three. We also noticed that if the measures studied in our five scenarios are taken separately then the second wave might occur at least as far as the parameter values remain unchanged.

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Section: Resultsmentioning

confidence: 99%

Section: Model Parametersmentioning

confidence: 99%

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A model of COVID-19 transmission to understand the effectiveness of the containment measures: application to data from France

Zongo¹,

Zorom

Mophou

et al. 2020

Epidemiol. Infect.

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show abstract

“…COVID-19 asymptomatic infections refer to those positive in nucleic acid testing with nasopharyngeal swabs but developing no novel coronavirus-related symptoms, such as fever, upper respiratory symptoms (cough and sore throat), fatigue, and gastrointestinal symptoms (for example, diarrhea). They are not referred to as "patients" due to the lack of symptoms [6], but they spread the virus easily while keeping frequent contact with others due to their unawareness of the infection [6,23]. The main reasons for asymptomatic infections might be that the infections are yet to develop clinical manifestations in the early stage of disease treatment or the individuals are strongly immune and develop no clinical manifestations after infection [24].…”

Section: Discussionmentioning

confidence: 99%

The Asymptomatic Infection of COVID-19 Risen in Imported Population in Shenzhen, China

Chen¹,

Ai²,

Huang

et al. 2020

Preprint

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Background As of July 24 2020, the global reported number of COVID-19 cases was > 15.4 millions, with over 640,000 deaths. The present study aimed to carry out an epidemiological analysis of confirmed cases and asymptomatic infections in Shenzhen City to provide scientific reference for the prevention and control of COVID-19. Methods The epidemiological information of the 462 confirmed cases and 45 asymptomatic infections from January 19th to June 30th was collected in Shenzhen City, Southern China, and a descriptive analysis was performed. Results A total of 462 confirmed COVID-19 cases from January 19 to April 30, 2020 were reported in Shenzhen City, including 423 domestic cases (91.56%) and 39 imported cases (8.44%) who came back from other countries. Among domestic cases, the majority were cases imported from Hubei Province (n = 312, 67.53%), followed by local ones (n = 69, 14.94%). During the same period, a total of 45 asymptomatic infections were reported in Shenzhen City, including 31 local ones (68.89%) and 14 imported from abroad (31.11%). The proportion of asymptomatic infections in Shenzhen City was increasing over time (Z = 13.1888, P < 0.0001). The total number of local asymptomatic infections in Shenzhen City exceeded as the same pattern as that in other provinces (χ2 = 118.830, P < 0.0001). The proportion of asymptomatic infections among cases imported from abroad was higher than that of the same in domestic cases (χ2 = 22.5121, P < 0.0001, OR = 4.8983, 95%: 2.4052, 9.9756). No statistical significance was noted in the proportions of asymptomatic infections among imported cases from different countries (χ2 = 7.7202, P = 0.6561). Conclusions The majority of COVID-19 cases in Shenzhen City were imported cases who came back from Hubei Province in the early stage (before 1st March, 2020) and from abroad in the later stage (after 1st April, 2020). Scientific and effective prevention and control measures have resulted in only a few local infections in Shenzhen City. Asymptomatic infections accounted for an increasing proportion among cases imported from abroad, indicating that the prevention measures carried out in Shenzhen City did avoid the import of infected cases. Improving the detection capability to identify asymptomatic infections as early as possible will be of significance for the control outbreak of COVID-19.

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“…COVID-19 showed typical respiratory symptom (such as fever, cough and lung damage) and some other symptoms such as fatigue, myalgia, and diarrhea 2 . Many studies have found that even asymptomatic people also have strong infectivity 3,4 . At present, speci c antiviral drugs or vaccines currently have not been available for the treatment.…”

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confidence: 99%

The Important Herbal Pair for the Treatment of COVID-19 and Its Possible Mechanisms

Xia

Zhong

Gao

et al. 2020

Preprint

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Background: Corona Virus Disease 2019 (COVID-19) is an unprecedented disaster for people around the world. Many studies have shown that traditional Chinese medicines(TCM) are indeed effective in treating COVID-19. However, it is a hard work to find the most effective combination laws among numerous herbs as well as its potential mechanisms. The purpose of this article is to explore the combination laws of traditional Chinses medicine(TCM) prescriptions and pick out the most important herbal pair for treating COVID-19 and analyze the active components and potential mechanisms. Methods: We first systematically sorted out the TCM prescriptions recommended by leading experts for treating COVID-19 and the specific herbs they contained in different stages of disease. Next, the association rule approach was employed to examine the distribution and combination laws among these TCM prescription, and then picked out the most important herbal pair. On this basis, we further investigated the active ingredients and potential targets in the selected herbal pair by a network pharmacology approach. Result: We obtained 32 association rules for herb combinations in the process of TCM treatment for COVID-19. It was found that the combination of Amygdalus Communis Vas(ACV) and Ephedra sinica Stapf (ESS) had the highest confidence degree and lift value as well as high support degree, which can be used in almost all stages of COVID-19, so ACV and ESS (AE) was selected as the most important herbal pair. There were 26 active ingredients and 44 potential targets, which may be relate to the herbal pair of AE against COVID-19. The main active ingredients of AE against COVID-19 are quercetin, kaempferol, luteolin and the potential important targets are Interleukin 6 (IL-6), Mitogen-activated Protein Kinase 1 (MAPK)1, MAPK8, Interleukin-1β (IL-1β), Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) p65 subunit (RELA) and so on. The protein-protein interaction (PPI) cluster demonstrated that IL-6 was the seed in the cluster, which plays an important role in connecting other nodes in the PPI network. The significant pathways mainly involved in tumor necrosis factor (TNF), Toll-like receptor (TLR), hypoxia-inducible factor-1 (HIF-1), nucleotide-binding oligomerization domain (NOD)-like receptor(NLRs). Conclusion: Amygdalus Communis Vas and Ephedra sinica Stapf was the most important herbal pair in the treatment of COVID-19. The main active ingredients of AE against COVID-19 were quercetin, kaempferol, luteolin and the important targets were IL-6，MAPK1, MAPK8, IL-1β, RELA and so on. AE may have therapeutic effects against COVID-19 by affecting the pathological processes such as inflammatory and immune responses, cell apoptosis, hypoxia damage and other pathological processes through multiple components, multiple targets and multiple pathways.

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COVID-19: asymptomatic carrier transmission is an underestimated problem

Cited by 139 publications

References 11 publications

A model of COVID-19 transmission to understand the effectiveness of the containment measures: application to data from France

A model of COVID-19 transmission to understand the effectiveness of the containment measures: application to data from France

The Asymptomatic Infection of COVID-19 Risen in Imported Population in Shenzhen, China

The Important Herbal Pair for the Treatment of COVID-19 and Its Possible Mechanisms

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