Estimating number of global importations of COVID-19 from Wuhan, risk of transmission outside mainland China and COVID-19 introduction index between countries outside mainland China

Sun, Haoyang; Dickens, Borame Sue Lee; Chen, Mark; Cook, Alex R.; Clapham, Hannah E.

doi:10.1101/2020.02.17.20024075

Cited by 11 publications

(21 citation statements)

References 14 publications

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“…We confirm by simulated quantification evidence that the traffic blockage is effective in controlling the epidemic of COVID-19, and the quarantine is a more effective way to help the public to prevent cross-infection. With the development of the epidemic, we have to admit the fact that there are still a number of population who are exposed to the COVID-19 without clinical symptoms [18][19][20]. Those population may carry the COVID-19 for several days and might infect others who are closely contacting with, which makes the potentional risk.…”

Section: Discussionmentioning

confidence: 99%

Estimating the Efficacy of Quarantine and Traffic Blockage for the Epidemic Caused by 2019-nCoV (COVID-19):A Simulation Analysis

Liu

et al. 2020

Preprint

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Background: Since the 2019-nCoV outbreaks in Wuhan, China, the cumulative number of confirmed cases is increasing every day, and a large number of populations all over the world are at risk. The quarantine and traffic blockage can alleviate the risk of the epidemic and the infections, henceforth evaluating the efficacy of such actions is essential to inform policy makers and raise the public awareness of the importance of self-isolation and quarantine. Method:We collected confirmed case data and the migration data, and introduced the quarantine factor and traffic blockage factor to the Flow-SEIR model. By varying the quarantine factor and traffic blockage factor, we simulated the change of the peak number and arrival time of infections, then the efficacy of these two intervation measures can be analyzed in our simulation. In our study, the self-protection at home is also included in quarantine. Results:In the simulated results, the quarantine and traffic blockage are effective for epidemic control. For Hubei province, the current quarantine factor is estimaed to be 0.405, which means around 40.5% of suceptibles who are close contacting with are in quarantine, and the current traffic blockage factor is estimaed to be 0.66, which indicates around 34% of suceptibles who had flowed out from Hubei. For the other provinces outside Hubei, the current quarantine factor is estimated to be 0.285, and the current traffic blockage factor is estimated to be 0.26. With the quarantine and traffic blockage factor increasing, the number of infections decrease dramatically. We also simulated the start dates of quarantine and traffic blockage at four time points, the simulated results show that the early of warning is also effective for epidemic containing.However, provincial level traffic blockage can only alleviate 21.06% -22.38% of the peak number of infections. In general, the quarantine is much more effective than the traffic blockage control.

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Section: Discussionmentioning

confidence: 99%

Estimating the Efficacy of Quarantine and Traffic Blockage for the Epidemic Caused by 2019-nCoV (COVID-19):A Simulation Analysis

Liu

et al. 2020

Preprint

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“…There was much discussion at the time whether the lack of reported imported cases in Africa was because imported cases were not being picked up. This may be some of the story, but our analysis would suggest that this was not the whole story, and it was more that the early risk of importation into Africa was lower than other places [23]. However the results we present in this paper estimate that this risk has dramatically increased with the spread of the virus in Europe and the USA.…”

Section: Discussionmentioning

confidence: 64%

“…As of July 15 th 2020, South Africa had reported the highest number of cases at 298,292 [4], and we estimated South Africa to have had one of the highest numbers of imported cases from the new epi-centres, although it was also rated highest at risk in Africa of importations from China in previous analysis [6]. Senegal is one of the countries for whom the risk has notably increased from the risk of importation from China as estimated in previous analyses [6,23]. We only considered importations from the major epicentres in Europe and America, and so the number of importations from all countries will be even higher.…”

Section: Discussionmentioning

confidence: 67%

“…In the first wave of importations of cases from Wuhan, China, to other places outside China we estimated that most places at risk were in Asia, Europe and USA [23].…”

Section: Discussionmentioning

confidence: 99%

“…Though there were links between China and African countries, these were fewer than those between China and the rest of Asia, Europe and USA [23]. The shut down in China severely curtailed continuing importations out of China and so these importations rapidly stopped.…”

Section: Discussionmentioning

confidence: 99%

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Importations of COVID-19 into African countries and risk of onward spread

et al. 2020

Self Cite

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Background: The emergence of a novel coronavirus (SARS-CoV-2) in Wuhan, China, at the end of 2019 has caused widespread transmission around the world. As new epicentres in Europe and America have arisen, of particular concern is the increased number of imported coronavirus disease 2019 (COVID-19) cases in Africa, where the impact of the pandemic could be more severe. We aim to estimate the number of COVID-19 cases imported from 12 major epicentres in Europe and America to each African country, as well as the probability of reaching 10,000 cases in total by the end of March, April, May, and June following viral introduction. Methods: We used the reported number of cases imported from the 12 major epicentres in Europe and America to Singapore, as well as flight data, to estimate the number of imported cases in each African country. Under the assumption that Singapore has detected all the imported cases, the estimates for Africa were thus conservative. We then propagated the uncertainty in the imported case count estimates to simulate the onward spread of the virus, until 10,000 cases are reached or the end of June, whichever is earlier. Specifically, 1,000 simulations were run separately under four different combinations of parameter values to test the sensitivity of our results. Results: We estimated Morocco, Algeria, South Africa, Egypt, Tunisia, and Nigeria as having the largest number of COVID-19 cases imported from the 12 major epicentres. Based on our 1,000 simulation runs, Morocco and Algeria's estimated probability of reaching 10,000 cases by end of March was close to 100% under all scenarios. In particular, we identified countries with less than 1,000 cases in total reported by end of June whilst the estimated probability of reaching 10,000 cases by then was higher than 50% even under the most optimistic scenario. Conclusions: Our study highlights particular countries that are likely to reach (or have reached) 10,000 cases far earlier than the reported data suggest, calling for the prioritization of resources to mitigate the further spread of the epidemic.

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Diagnosis of COVID-19, vitality of emerging technologies and preventive measures

Asif

Xiao

et al. 2021

Chemical Engineering Journal

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Estimating number of global importations of COVID-19 from Wuhan, risk of transmission outside mainland China and COVID-19 introduction index between countries outside mainland China

Abstract: Background

Cited by 11 publications

References 14 publications

Estimating the Efficacy of Quarantine and Traffic Blockage for the Epidemic Caused by 2019-nCoV (COVID-19):A Simulation Analysis

Estimating the Efficacy of Quarantine and Traffic Blockage for the Epidemic Caused by 2019-nCoV (COVID-19):A Simulation Analysis

Importations of COVID-19 into African countries and risk of onward spread

Diagnosis of COVID-19, vitality of emerging technologies and preventive measures

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