ISSN 0253-2778

CN 34-1054/N

Open AccessOpen Access JUSTC Original Paper

Forecast and analysis of the epidemics trend of COVID-19 in the United States by TRP-SEAMRD model

Cite this:
https://doi.org/10.3969/j.issn.0253-2778.2020.08.012
  • Received Date: 26 June 2020
  • Accepted Date: 22 August 2020
  • Rev Recd Date: 22 August 2020
  • Publish Date: 31 August 2020
  • The traditional SEIR(susceptible-exposed-infectious-recovered/removed) model is a simplified dynamical predictive model which does not consider the impact of changes in the anti-epidemic policy. We take the US anti-epidemic policy and the incubation period characteristic of COVID-19 into account to propose the TRP-SEAMRD(test-restricted-phased SEAMRD) model for the pandemic in US. The model fits well with the figures of COVID-19 infections, recovery and death in the United States during February ~ August 2020. According to the data generated from the model, some of the characteristics of COVID-19 can be abstracted. Based on the TRP-SEAMRD model, we can analyze the impact of the improper anti-epidemic policy at the early stage of the epidemic.The effect of the subsequent “stay at home”epidemic controlling measures is also considered and analyzed. Finally, future development of the pandemic in the US under different degrees of social control is simulated,offering a reference for formulating scientific anti-epidemic measures.
    The traditional SEIR(susceptible-exposed-infectious-recovered/removed) model is a simplified dynamical predictive model which does not consider the impact of changes in the anti-epidemic policy. We take the US anti-epidemic policy and the incubation period characteristic of COVID-19 into account to propose the TRP-SEAMRD(test-restricted-phased SEAMRD) model for the pandemic in US. The model fits well with the figures of COVID-19 infections, recovery and death in the United States during February ~ August 2020. According to the data generated from the model, some of the characteristics of COVID-19 can be abstracted. Based on the TRP-SEAMRD model, we can analyze the impact of the improper anti-epidemic policy at the early stage of the epidemic.The effect of the subsequent “stay at home”epidemic controlling measures is also considered and analyzed. Finally, future development of the pandemic in the US under different degrees of social control is simulated,offering a reference for formulating scientific anti-epidemic measures.
  • loading
  • [1]
    CARCIONE J M, SANTOS J E, BAGAINI C, et al. A simulation of a COVID-19 epidemic based on a deterministic SEIR model[EB/OL]. (2020-05-10)[2020-08-20]. https://arxiv.org/abs/2004.03575.
    [2]
    TANG Z, LI X B, LI H Q. Prediction of new coronavirus infection based on a modified SEIR model[EB/OL]. (2020-03-06)[2020-08-20].https://doi.org/10.1101/2020.03.03.20030858.
    [3]
    WU J T, LEUNG K, LEUNG G M. Nowcasting and forecasting the potential domestic and international spread of the 2019-nCoV outbreak originating in Wuhan, China: a modelling study[J]. Lancet, 2020, 395(10225): 689–697.
    [4]
    PANDEY G, CHAUDHARY P, GUPTA R, et al. SEIR and regression model based COVID-19 outbreak predictions in India[EB/OL]. (2020-04-01)[2020-08-20].https://arxiv.org/abs/2004.00958.
    [5]
    SANTOS J E,CARCIONE J M, SAVIOLI G B, et al. A numerical simulation of the COVID-19 epidemic in Argentina using the SEIR model[EB/OL]. (2020-07-15)[2020-08-20]. https://arxiv.org/abs/2005.06297.
    [6]
    HULT H, FAVERO M. Estimates of the proportion of SARS-CoV-2 infected individuals in Sweden[EB/OL]. (2020-05-25)[2020-08-20]. https://arxiv.org/abs/2005.13519.
    [7]
    DEEB O E, JALLOUL M. The dynamics of COVID-19 spread in Lebanon[EB/OL]. (2020-05-14)[2020-07-20].https://arxiv.org/abs/2005.07251v1.
    [8]
    ZHANG YZ, HOLMES E C. A genomic perspective on the origin and emergence of SARS-CoV-2[J]. Cell, 2020, 181(2): 223–227.
    [9]
    ARENTZ M, YIM E, KLAFF L, et al. Characteristics and Outcomes of 21 Critically Ill Patients With COVID-19 in Washington State[J]. JAMA, 2020, 323(16):1612-1614.
    [10]
    LIVINGSTON E, BUCHER K. Coronavirus disease 2019 (COVID-19) in Italy[J]. JAMA, 2020, 323(14): 1335.
    [11]
    ALTIERI N, BARTER R L, DUNCAN J, et al. Curating a COVID-19 data repository and forecasting county-level death counts in the United States[EB/OL]. (2020-05-16)[2020-07-20]. https://arxiv.org/abs/2005.07882v1.
    [12]
    MAHAJAN A, SOLANKI R, NAMITHA A S. An Epidemic Model SIPHERD and its application for prediction of the spread of COVID-19 infection for India and USA[EB/OL]. (2020-05-11)[2020-08-20]. https://arxiv.org/abs/2005.00921.
    [13]
    WANG L, WANG G N, GAO L,et al. Spatiotemporal dynamics, nowcasting and forecasting of COVID-19 in the United States[EB/OL]. (2020-04-30)[2020-08-20]. https://arxiv.org/abs/2004.14103v2 .
    [14]
    XU C H, YU Y G, YANG Q C, et al. Forecast analysis of the epidemics trend of COVID-19 in the United States by a generalized fractional-order SEIR model[EB/OL]. (2020-04-29)[2020-08-20]. https://arxiv.org/abs/2004.12541.
    [15]
    SRIVASTAVA A, PRASANNA V K. Learning to forecast and forecasting to learn from the COVID-19 pandemic[EB/OL]. (2020-05-04)[2020-08-20]. https://arxiv.org/abs/2004.11372.
    [16]
    JOHNDROW J, LUM K, GARGIULOM, et al. Estimating the number of SARS-CoV-2 infections and the impact of social distancing in the United States[EB/OL]. (2020-04-19)[2020-08-20]. https://arxiv.org/abs/2004.02605.
    [17]
    BAYHAM J, FENICHEL E P. Impact of school closures for COVID-19 on the US health-care workforce and net mortality: a modelling study[J]. The Lancet Public Health, 2020, 5(5): e271–e278.
    [18]
    MOLLALO A, VAHEDI B, RIVERA K M. GIS-based spatial modeling of COVID-19 incidence rate in the continental United States[J]. Science of The Total Environment, 2020, 728: 138884.
    [19]
    LAUER S A, GRANTZ K H, BI Q F, et al. The incubation period of coronavirus disease 2019 (COVID-19) from publicly reported confirmed cases: Estimation and application[J]. Annals of Internal Medicine, 2020, 172(9): 577–582.
    [20]
    LI Q, GUAN X H, WU P, etal. Early transmission dynamics in Wuhan, China, of novel coronavirus–infected pneumonia[J]. The New England Journal of Medicine,2020, 382(13): 1199–1207.
    [21]
    BACKER J A, KLINKENBERG D, WALLINGA J. Incubation period of 2019 novel coronavirus (2019-nCoV) infections among travellers from Wuhan, China, 20–28 January 2020[J]. EuroSurveill, 2020, 25(5):2000062.
    [22]
    GUANW J, NI Z Y, HU Y, et al. Clinical characteristics of coronavirus disease 2019 in China[J]. The NewEngland Journal of Medicine, 2020, 382(18):1708-1720.
    [23]
    FANELLI D,PIAZZA F. Analysis and forecast of COVID-19 spreading in China, Italy and France[J]. Chaos, Solitons & Fractals, 2020, 134: 109761.
    [24]
    国家卫生健康委员会宣传司.2020年2月17日新闻发布会文字实录[EB/OL]. (2020-02-17)[2020-08-20]. www.nhc.gov.cn/xcs/yqfkdt/202002/f12a62d10c2a48c6895cedf2faea6e1f.shtml.
    [25]
    Washington Post Staff.What we know about delays in coronavirus testing[EB/OL].(2020-04-18)[2020-08-20]. https://www.washingtonpost.com/investigations/2020/04/18/timeline-coronavirus-testing/.
    [26]
    REDFIELD R R.Coronavirus Disease 2019: The U.S. and International Response[EB/OL]. (2020-02-27)[2020-08-20]. https://www.cdc.gov/washington/testimony/2020/t20200127.htm.
    [27]
    SHIEBER J.FDA allows new diagnostic technologies to test for coronavirus before receiving emergency approvals[EB/OL]. (2020-03-01)[2020-08-20]. https://techcrunch.com/2020/02/29/fda-allows-new-diagnostic-technologies-to-test-for-coronavirus-before-receiving-emergency-approvals/.
    [28]
    Quest Diagnostics.Quest Diagnostics to Launch Coronavirus Disease 2019 (COVID-19) Test[EB/OL].(2020-03-05)[2020-08-20]. https://newsroom.questdiagnostics.com/2020-03-05-Quest-Diagnostics-to-Launch-Coronavirus-Disease-2019-COVID-19-Test.
    [29]
    亚时财经.CDC、斯坦福大学分别研发全新新冠病毒检测试剂盒[EB/OL].(2020-03-08)[2020-08-20]. http://atimescn.com/TechnologyView-12714.html.
    [30]
    HONG N, MCKINLEY J, SANDOVAL E, et al.2 New York State Lawmakers Test Positive for Coronavirus[EB/OL]. (2020-03-14)[2020-08-20]. https://www.nytimes.com/2020/03/14/nyregion/coronavirus-ny.html.
    [31]
    SHAPIRO E.New York City Public Schools to Close to Slow Spread of Coronavirus[EB/OL]. (2020-03-15)[2020-08-20]. https://www.nytimes.com/2020/03/15/nyregion/nyc-schools-closed.html.
    [32]
    LEE A. These states have implemented stay-at-home orders. Here's what that means for you[EB/OL]. (2020-04-07)[2020-08-20]. https://www.cnn.com/2020/03/23/us/coronavirus-which-states-stay-at-home-order-trnd/index.html.
    [33]
    The White House.15 Days to Slow the Spread[EB/OL]. (2020-03-16)[2020-08-20]. https://www.whitehouse.gov/articles/15-days-slow-spread/.
    [34]
    The White House.Executive Order on Prioritizing and Allocating Health and Medical Resources to Respond to the Spread of Covid-19[EB/OL]. (2020-03-18)[2020-08-20]. https://www.whitehouse.gov/presidential-actions/executive-order-prioritizing-allocating-health-medical-resources-respond-spread-covid-19/.
    [35]
    The White House.Statement from the President Regarding the Defense Production Act[EB/OL]. (2020-04-02)[2020-08-20]. https://www.whitehouse.gov/briefings-statements/statement-president-regarding-defense-production-act-2/.
    [36]
    FEUER W.Vice President Mike Pence says 16 states have unveiled plans to lift coronavirus restrictions[EB/OL]. (2020-04-23)[2020-08-20]. https://www.cnbc.com/2020/04/23/pence-says-16-states-have-released-plans-to-lift-coronavirus-restrictions.html.
    [37]
    SHALBY C.L.A. County working to ease stay-at-home order by May[EB/OL].(2020-04-28)[2020-08-20].https://www.latimes.com/california/story/2020-04-28/l-a-county-working-to-ease-stay-at-home-order-by-may.
    [38]
    LIN II R G,MONEY L, WIGGLESWORTH A .California faces growing pressure to ease stay-at-home rules, at least in some regions[EB/OL].(2020-04-27)[2020-08-20]. https://www.latimes.com/california/story/2020-04-27/coronavirus-reopening-california-stay-at-home-rules.
    [39]
    MCKINLEY J.New York to Begin Limited Reopening in Upstate Region[EB/OL].(2020-05-11)[2020-08-20]. https://www.nytimes.com/2020/05/11/nyregion/reopen-new-york-coronavirus.html.
    [40]
    The New York Times.See Reopening Plans and Mask Mandates for All 50 States[EB/OL].(2020-04-24)[2020-08-20]. https://www.nytimes.com/interactive/2020/us/states-reopen-map-coronavirus.html.
    [41]
    Wikipedia.George Floyd[EB/OL].[2020-08-20].https://en.m.wikipedia.org/wiki/George_Floyd.
    [42]
    BBC News. George Floyd death homicide, official postmortem declares[EB/OL].(2020-06-02)[2020-08-20].https://www.bbc.com/news/world-us-canada-52886593.
    [43]
    TAYLOR D B. George Floyd Protests: A Timeline[EB/OL].(2020-06-02)[2020-08-20].https://www.nytimes.com/article/george-floyd-protests-timeline.html.
    [44]
    AIZURA A. A Mask and A Target Cart: Minneapolis Riot[EB/OL].(2020-05-30)[2020-08-20]. https://thenewinquiry.com/a-mask-and-a-target-cart-minneapolis-riots/.
    [45]
    SMITH-SCHOENWALDER C. Weekend Protests Over George Floyd's Death Spread Across the U.S. [EB/OL]. (2020-06-01) [2020-08-20]. https://www.usnews.com/news/national-news/articles/2020-06-01/dc-fires-protests-over-george-floyds-death-bring-unrest-to-trumps-backyard.
    [46]
    National Center for Immunization and Respiratory Diseases (NCIRD), Division of Viral Diseases.Developing Guidance to Protect the Public’s Health[EB/OL].(2020-07-01)[2020-08-20]. https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/about-epidemiology/protect-public-health.html.
    [47]
    National Center for Immunization and Respiratory Diseases (NCIRD), Division of Viral Diseases. Guidance for Organizing Large Events and Gatherings[EB/OL]. (2020-07-01)[2020-08-20]. https://www.cdc.gov/coronavirus/2019-ncov/community/large-events/considerations-for-events-gatherings.html.
    [48]
    Centers for Disease Control and Prevention. CDC calls on Americans to wear masks to prevent COVID-19 spread[EB/OL]. (2020-07-14)[2020-08-20]. https://www.cdc.gov/media/releases/2020/p0714-americans-to-wear-masks.html.
    [49]
    CDC COVID-19 Response Team. Severe outcomes among patients with coronavirus disease 2019 (COVID-19)—United States, February 12–March 16, 2020[J]. MMWR.Morbidity and Mortality Weekly Report, 2020, 69:343-346;doi: 10.15585/mmwr.mm6912e2.
    [50]
    BHATRAJU P K, GHASSEMIEH B J,NICHOLS M, et al. Covid-19 in critically Ill patients in the Seattle region — Case series[J]. TheNew England Journal of Medicine,2020, 382(21): 2012–2022.
    [51]
    National Center for Immunization and Respiratory Diseases (NCIRD), Division of Viral Diseases.COVID-19Testing Overview[EB/OL].[2020-08-20]. https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/testing.html.
    [52]
    SMITH-SCHOENWALDER C. Trump Grants More Financing for Pharmaceutical Companies Amid Pandemic [EB/OL]. (2020-05-14)[2020-08-20]. https://www.usnews.com/news/national-news/articles/2020-05-14/trump-grants-more-financing-for-pharmaceuticals-amid-coronavirus-pandemic.
    [53]
    KORBERB, FISCHER W M, GNANAKARAN S, et al. Spike mutation pipeline reveals the emergence of a more transmissible form of SARS-CoV-2[EB/OL]. (2020-05-05)[2020-08-10].https://doi.org/10.1101/2020.04.29.069054.
    [54]
    KORBER B, FISCHER W M,GNANAKARAN S, et al. Tracking changes in SARS-CoV-2 Spike: Evidence that D614G increases infectivity of the COVID-19 virus[J]. Cell, 2020, 182(4): 812-827.e19.
    [55]
    FOX M.Study confirms new version of coronavirus spreads faster, but doesn’t make people sicker[EB/OL]. (2020-07-03)[2020-08-20]. https://edition.cnn.com/2020/07/02/health/coronavirus-mutation-spread-study/index.html.)
  • 加载中

Catalog

    [1]
    CARCIONE J M, SANTOS J E, BAGAINI C, et al. A simulation of a COVID-19 epidemic based on a deterministic SEIR model[EB/OL]. (2020-05-10)[2020-08-20]. https://arxiv.org/abs/2004.03575.
    [2]
    TANG Z, LI X B, LI H Q. Prediction of new coronavirus infection based on a modified SEIR model[EB/OL]. (2020-03-06)[2020-08-20].https://doi.org/10.1101/2020.03.03.20030858.
    [3]
    WU J T, LEUNG K, LEUNG G M. Nowcasting and forecasting the potential domestic and international spread of the 2019-nCoV outbreak originating in Wuhan, China: a modelling study[J]. Lancet, 2020, 395(10225): 689–697.
    [4]
    PANDEY G, CHAUDHARY P, GUPTA R, et al. SEIR and regression model based COVID-19 outbreak predictions in India[EB/OL]. (2020-04-01)[2020-08-20].https://arxiv.org/abs/2004.00958.
    [5]
    SANTOS J E,CARCIONE J M, SAVIOLI G B, et al. A numerical simulation of the COVID-19 epidemic in Argentina using the SEIR model[EB/OL]. (2020-07-15)[2020-08-20]. https://arxiv.org/abs/2005.06297.
    [6]
    HULT H, FAVERO M. Estimates of the proportion of SARS-CoV-2 infected individuals in Sweden[EB/OL]. (2020-05-25)[2020-08-20]. https://arxiv.org/abs/2005.13519.
    [7]
    DEEB O E, JALLOUL M. The dynamics of COVID-19 spread in Lebanon[EB/OL]. (2020-05-14)[2020-07-20].https://arxiv.org/abs/2005.07251v1.
    [8]
    ZHANG YZ, HOLMES E C. A genomic perspective on the origin and emergence of SARS-CoV-2[J]. Cell, 2020, 181(2): 223–227.
    [9]
    ARENTZ M, YIM E, KLAFF L, et al. Characteristics and Outcomes of 21 Critically Ill Patients With COVID-19 in Washington State[J]. JAMA, 2020, 323(16):1612-1614.
    [10]
    LIVINGSTON E, BUCHER K. Coronavirus disease 2019 (COVID-19) in Italy[J]. JAMA, 2020, 323(14): 1335.
    [11]
    ALTIERI N, BARTER R L, DUNCAN J, et al. Curating a COVID-19 data repository and forecasting county-level death counts in the United States[EB/OL]. (2020-05-16)[2020-07-20]. https://arxiv.org/abs/2005.07882v1.
    [12]
    MAHAJAN A, SOLANKI R, NAMITHA A S. An Epidemic Model SIPHERD and its application for prediction of the spread of COVID-19 infection for India and USA[EB/OL]. (2020-05-11)[2020-08-20]. https://arxiv.org/abs/2005.00921.
    [13]
    WANG L, WANG G N, GAO L,et al. Spatiotemporal dynamics, nowcasting and forecasting of COVID-19 in the United States[EB/OL]. (2020-04-30)[2020-08-20]. https://arxiv.org/abs/2004.14103v2 .
    [14]
    XU C H, YU Y G, YANG Q C, et al. Forecast analysis of the epidemics trend of COVID-19 in the United States by a generalized fractional-order SEIR model[EB/OL]. (2020-04-29)[2020-08-20]. https://arxiv.org/abs/2004.12541.
    [15]
    SRIVASTAVA A, PRASANNA V K. Learning to forecast and forecasting to learn from the COVID-19 pandemic[EB/OL]. (2020-05-04)[2020-08-20]. https://arxiv.org/abs/2004.11372.
    [16]
    JOHNDROW J, LUM K, GARGIULOM, et al. Estimating the number of SARS-CoV-2 infections and the impact of social distancing in the United States[EB/OL]. (2020-04-19)[2020-08-20]. https://arxiv.org/abs/2004.02605.
    [17]
    BAYHAM J, FENICHEL E P. Impact of school closures for COVID-19 on the US health-care workforce and net mortality: a modelling study[J]. The Lancet Public Health, 2020, 5(5): e271–e278.
    [18]
    MOLLALO A, VAHEDI B, RIVERA K M. GIS-based spatial modeling of COVID-19 incidence rate in the continental United States[J]. Science of The Total Environment, 2020, 728: 138884.
    [19]
    LAUER S A, GRANTZ K H, BI Q F, et al. The incubation period of coronavirus disease 2019 (COVID-19) from publicly reported confirmed cases: Estimation and application[J]. Annals of Internal Medicine, 2020, 172(9): 577–582.
    [20]
    LI Q, GUAN X H, WU P, etal. Early transmission dynamics in Wuhan, China, of novel coronavirus–infected pneumonia[J]. The New England Journal of Medicine,2020, 382(13): 1199–1207.
    [21]
    BACKER J A, KLINKENBERG D, WALLINGA J. Incubation period of 2019 novel coronavirus (2019-nCoV) infections among travellers from Wuhan, China, 20–28 January 2020[J]. EuroSurveill, 2020, 25(5):2000062.
    [22]
    GUANW J, NI Z Y, HU Y, et al. Clinical characteristics of coronavirus disease 2019 in China[J]. The NewEngland Journal of Medicine, 2020, 382(18):1708-1720.
    [23]
    FANELLI D,PIAZZA F. Analysis and forecast of COVID-19 spreading in China, Italy and France[J]. Chaos, Solitons & Fractals, 2020, 134: 109761.
    [24]
    国家卫生健康委员会宣传司.2020年2月17日新闻发布会文字实录[EB/OL]. (2020-02-17)[2020-08-20]. www.nhc.gov.cn/xcs/yqfkdt/202002/f12a62d10c2a48c6895cedf2faea6e1f.shtml.
    [25]
    Washington Post Staff.What we know about delays in coronavirus testing[EB/OL].(2020-04-18)[2020-08-20]. https://www.washingtonpost.com/investigations/2020/04/18/timeline-coronavirus-testing/.
    [26]
    REDFIELD R R.Coronavirus Disease 2019: The U.S. and International Response[EB/OL]. (2020-02-27)[2020-08-20]. https://www.cdc.gov/washington/testimony/2020/t20200127.htm.
    [27]
    SHIEBER J.FDA allows new diagnostic technologies to test for coronavirus before receiving emergency approvals[EB/OL]. (2020-03-01)[2020-08-20]. https://techcrunch.com/2020/02/29/fda-allows-new-diagnostic-technologies-to-test-for-coronavirus-before-receiving-emergency-approvals/.
    [28]
    Quest Diagnostics.Quest Diagnostics to Launch Coronavirus Disease 2019 (COVID-19) Test[EB/OL].(2020-03-05)[2020-08-20]. https://newsroom.questdiagnostics.com/2020-03-05-Quest-Diagnostics-to-Launch-Coronavirus-Disease-2019-COVID-19-Test.
    [29]
    亚时财经.CDC、斯坦福大学分别研发全新新冠病毒检测试剂盒[EB/OL].(2020-03-08)[2020-08-20]. http://atimescn.com/TechnologyView-12714.html.
    [30]
    HONG N, MCKINLEY J, SANDOVAL E, et al.2 New York State Lawmakers Test Positive for Coronavirus[EB/OL]. (2020-03-14)[2020-08-20]. https://www.nytimes.com/2020/03/14/nyregion/coronavirus-ny.html.
    [31]
    SHAPIRO E.New York City Public Schools to Close to Slow Spread of Coronavirus[EB/OL]. (2020-03-15)[2020-08-20]. https://www.nytimes.com/2020/03/15/nyregion/nyc-schools-closed.html.
    [32]
    LEE A. These states have implemented stay-at-home orders. Here's what that means for you[EB/OL]. (2020-04-07)[2020-08-20]. https://www.cnn.com/2020/03/23/us/coronavirus-which-states-stay-at-home-order-trnd/index.html.
    [33]
    The White House.15 Days to Slow the Spread[EB/OL]. (2020-03-16)[2020-08-20]. https://www.whitehouse.gov/articles/15-days-slow-spread/.
    [34]
    The White House.Executive Order on Prioritizing and Allocating Health and Medical Resources to Respond to the Spread of Covid-19[EB/OL]. (2020-03-18)[2020-08-20]. https://www.whitehouse.gov/presidential-actions/executive-order-prioritizing-allocating-health-medical-resources-respond-spread-covid-19/.
    [35]
    The White House.Statement from the President Regarding the Defense Production Act[EB/OL]. (2020-04-02)[2020-08-20]. https://www.whitehouse.gov/briefings-statements/statement-president-regarding-defense-production-act-2/.
    [36]
    FEUER W.Vice President Mike Pence says 16 states have unveiled plans to lift coronavirus restrictions[EB/OL]. (2020-04-23)[2020-08-20]. https://www.cnbc.com/2020/04/23/pence-says-16-states-have-released-plans-to-lift-coronavirus-restrictions.html.
    [37]
    SHALBY C.L.A. County working to ease stay-at-home order by May[EB/OL].(2020-04-28)[2020-08-20].https://www.latimes.com/california/story/2020-04-28/l-a-county-working-to-ease-stay-at-home-order-by-may.
    [38]
    LIN II R G,MONEY L, WIGGLESWORTH A .California faces growing pressure to ease stay-at-home rules, at least in some regions[EB/OL].(2020-04-27)[2020-08-20]. https://www.latimes.com/california/story/2020-04-27/coronavirus-reopening-california-stay-at-home-rules.
    [39]
    MCKINLEY J.New York to Begin Limited Reopening in Upstate Region[EB/OL].(2020-05-11)[2020-08-20]. https://www.nytimes.com/2020/05/11/nyregion/reopen-new-york-coronavirus.html.
    [40]
    The New York Times.See Reopening Plans and Mask Mandates for All 50 States[EB/OL].(2020-04-24)[2020-08-20]. https://www.nytimes.com/interactive/2020/us/states-reopen-map-coronavirus.html.
    [41]
    Wikipedia.George Floyd[EB/OL].[2020-08-20].https://en.m.wikipedia.org/wiki/George_Floyd.
    [42]
    BBC News. George Floyd death homicide, official postmortem declares[EB/OL].(2020-06-02)[2020-08-20].https://www.bbc.com/news/world-us-canada-52886593.
    [43]
    TAYLOR D B. George Floyd Protests: A Timeline[EB/OL].(2020-06-02)[2020-08-20].https://www.nytimes.com/article/george-floyd-protests-timeline.html.
    [44]
    AIZURA A. A Mask and A Target Cart: Minneapolis Riot[EB/OL].(2020-05-30)[2020-08-20]. https://thenewinquiry.com/a-mask-and-a-target-cart-minneapolis-riots/.
    [45]
    SMITH-SCHOENWALDER C. Weekend Protests Over George Floyd's Death Spread Across the U.S. [EB/OL]. (2020-06-01) [2020-08-20]. https://www.usnews.com/news/national-news/articles/2020-06-01/dc-fires-protests-over-george-floyds-death-bring-unrest-to-trumps-backyard.
    [46]
    National Center for Immunization and Respiratory Diseases (NCIRD), Division of Viral Diseases.Developing Guidance to Protect the Public’s Health[EB/OL].(2020-07-01)[2020-08-20]. https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/about-epidemiology/protect-public-health.html.
    [47]
    National Center for Immunization and Respiratory Diseases (NCIRD), Division of Viral Diseases. Guidance for Organizing Large Events and Gatherings[EB/OL]. (2020-07-01)[2020-08-20]. https://www.cdc.gov/coronavirus/2019-ncov/community/large-events/considerations-for-events-gatherings.html.
    [48]
    Centers for Disease Control and Prevention. CDC calls on Americans to wear masks to prevent COVID-19 spread[EB/OL]. (2020-07-14)[2020-08-20]. https://www.cdc.gov/media/releases/2020/p0714-americans-to-wear-masks.html.
    [49]
    CDC COVID-19 Response Team. Severe outcomes among patients with coronavirus disease 2019 (COVID-19)—United States, February 12–March 16, 2020[J]. MMWR.Morbidity and Mortality Weekly Report, 2020, 69:343-346;doi: 10.15585/mmwr.mm6912e2.
    [50]
    BHATRAJU P K, GHASSEMIEH B J,NICHOLS M, et al. Covid-19 in critically Ill patients in the Seattle region — Case series[J]. TheNew England Journal of Medicine,2020, 382(21): 2012–2022.
    [51]
    National Center for Immunization and Respiratory Diseases (NCIRD), Division of Viral Diseases.COVID-19Testing Overview[EB/OL].[2020-08-20]. https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/testing.html.
    [52]
    SMITH-SCHOENWALDER C. Trump Grants More Financing for Pharmaceutical Companies Amid Pandemic [EB/OL]. (2020-05-14)[2020-08-20]. https://www.usnews.com/news/national-news/articles/2020-05-14/trump-grants-more-financing-for-pharmaceuticals-amid-coronavirus-pandemic.
    [53]
    KORBERB, FISCHER W M, GNANAKARAN S, et al. Spike mutation pipeline reveals the emergence of a more transmissible form of SARS-CoV-2[EB/OL]. (2020-05-05)[2020-08-10].https://doi.org/10.1101/2020.04.29.069054.
    [54]
    KORBER B, FISCHER W M,GNANAKARAN S, et al. Tracking changes in SARS-CoV-2 Spike: Evidence that D614G increases infectivity of the COVID-19 virus[J]. Cell, 2020, 182(4): 812-827.e19.
    [55]
    FOX M.Study confirms new version of coronavirus spreads faster, but doesn’t make people sicker[EB/OL]. (2020-07-03)[2020-08-20]. https://edition.cnn.com/2020/07/02/health/coronavirus-mutation-spread-study/index.html.)

    Article Metrics

    Article views (88) PDF downloads(154)
    Proportional views

    /

    DownLoad:  Full-Size Img  PowerPoint
    Return
    Return