PMC:7050133 / 20588-23698 JSONTXT

{"project":"LitCovid-PubTator","denotations":[{"id":"168","span":{"begin":177,"end":185},"obj":"Disease"},{"id":"169","span":{"begin":340,"end":348},"obj":"Disease"},{"id":"172","span":{"begin":716,"end":724},"obj":"Disease"},{"id":"173","span":{"begin":725,"end":746},"obj":"Disease"},{"id":"175","span":{"begin":592,"end":600},"obj":"Disease"},{"id":"177","span":{"begin":1650,"end":1658},"obj":"Disease"},{"id":"179","span":{"begin":2431,"end":2439},"obj":"Disease"},{"id":"182","span":{"begin":2893,"end":2901},"obj":"Disease"},{"id":"183","span":{"begin":2922,"end":2930},"obj":"Disease"}],"attributes":[{"id":"A168","pred":"tao:has_database_id","subj":"168","obj":"MESH:D007239"},{"id":"A169","pred":"tao:has_database_id","subj":"169","obj":"MESH:C000657245"},{"id":"A172","pred":"tao:has_database_id","subj":"172","obj":"MESH:C000657245"},{"id":"A173","pred":"tao:has_database_id","subj":"173","obj":"MESH:C000657245"},{"id":"A175","pred":"tao:has_database_id","subj":"175","obj":"MESH:C000657245"},{"id":"A177","pred":"tao:has_database_id","subj":"177","obj":"MESH:C000657245"},{"id":"A179","pred":"tao:has_database_id","subj":"179","obj":"MESH:C000657245"},{"id":"A182","pred":"tao:has_database_id","subj":"182","obj":"MESH:C000657245"},{"id":"A183","pred":"tao:has_database_id","subj":"183","obj":"MESH:C000657245"}],"namespaces":[{"prefix":"Tax","uri":"https://www.ncbi.nlm.nih.gov/taxonomy/"},{"prefix":"MESH","uri":"https://id.nlm.nih.gov/mesh/"},{"prefix":"Gene","uri":"https://www.ncbi.nlm.nih.gov/gene/"},{"prefix":"CVCL","uri":"https://web.expasy.org/cellosaurus/CVCL_"}],"text":"Exponential growth and detection rate\nThe observed F(x) fit the exponential model of Eq. 4 well with R2 = 0.9778. The estimated α =1.1070, representing the first person who was infected and ignited the epidemic. The estimated β =0.1716, representing the growth rate. Using this estimated growth rate, it takes only 4 days for the diagnosed COVID-19 to double.\nFigure 3 presents the daily detection rates, estimated with the fitted exponential model from day one of the epidemic to the last day of the study period. Based on findings in this figure and data from Figs. 1 and 2, we divided the COVID-19 epidemic during the first two months of the epidemic into five phases.\nFig. 3 Estimated daily detection rate Pi of COVID-19 (2019-nCoV) infection before, during and after declaration of the outbreak, the first 2 months of the Epidemic in China\nPhase 1 was from December 8 to 25, 2019. During this period, the detection rate Pi was high overall, with fluctuations around and above 100%. This was corresponding to the early period after the first suspected case was identified and diagnosed.\nPhase 2 was from December 26, 2019 to January 8, 2020, covering the New Year’s Day. The detection rate Pi fluctuated at around 50% with the lowest of 17% on December 31, 2019 and the highest of 108% on January 8.\nPhase 3 was from January 8 to 20, 2020, and it was featured with a progressive decline in the estimated Pi from 105% on January 8, 2020 to 1% on January 20, 2020. This progressive declining period was the time for the Chinese to prepare for the traditional Chinese New Year’s with the longest and highest level of celebration. Unfortunately, the COVID-19 as an outbreak was silently stepping in during this period.\nPhase 4 was from January 20 to 27, 2020 with the estimated Pi increased from 1% on January 20, 2020 to surpass 100%, and reached the peak of 170% on January 27, 2020. This period was corresponding to the initiation and progressive intensifying of the massive intervention organized and coordinated by the Central Government of China.\nPhase 5 started from January 27, 2020 to the end of the study period, corresponding to the sustained massive national efforts, plus frequent emphases. Different from the previous four phases, reductions in the estimated Pi during this phase were not an indication of under-detection but an indication of declines in the epidemic reflected by the detected and confirmed cases of COVID-19. This is because the model predicted Pi did not consider any interventions but natural growth of the epidemic.\nBased on Figs. 2 and 3 (Phase 4 and 5), three pieces of information can be derived: (1) The epidemic was highly sensitive to external interventions, supporting the nonlinear and chaotic characters revealed by the long latent period in the first three phases; (2) the massive national efforts were highly effective in detecting the detectable COVID-19; (3) signal for the COVID-19 in China to decline appeared on January 21 in 2020, 14 days before the start of eventual declines on February 4, as indicated by F ′  ′ (x) and F ′ (x) in Fig. 2 and Pi in Fig. 3."}

{"project":"LitCovid-PD-MONDO","denotations":[{"id":"T48","span":{"begin":101,"end":103},"obj":"Disease"},{"id":"T49","span":{"begin":340,"end":348},"obj":"Disease"},{"id":"T50","span":{"begin":592,"end":600},"obj":"Disease"},{"id":"T51","span":{"begin":716,"end":724},"obj":"Disease"},{"id":"T52","span":{"begin":725,"end":746},"obj":"Disease"},{"id":"T53","span":{"begin":737,"end":746},"obj":"Disease"},{"id":"T54","span":{"begin":1650,"end":1658},"obj":"Disease"},{"id":"T55","span":{"begin":2431,"end":2439},"obj":"Disease"},{"id":"T56","span":{"begin":2893,"end":2901},"obj":"Disease"},{"id":"T57","span":{"begin":2922,"end":2930},"obj":"Disease"}],"attributes":[{"id":"A48","pred":"mondo_id","subj":"T48","obj":"http://purl.obolibrary.org/obo/MONDO_0019903"},{"id":"A49","pred":"mondo_id","subj":"T49","obj":"http://purl.obolibrary.org/obo/MONDO_0100096"},{"id":"A50","pred":"mondo_id","subj":"T50","obj":"http://purl.obolibrary.org/obo/MONDO_0100096"},{"id":"A51","pred":"mondo_id","subj":"T51","obj":"http://purl.obolibrary.org/obo/MONDO_0100096"},{"id":"A52","pred":"mondo_id","subj":"T52","obj":"http://purl.obolibrary.org/obo/MONDO_0100096"},{"id":"A53","pred":"mondo_id","subj":"T53","obj":"http://purl.obolibrary.org/obo/MONDO_0005550"},{"id":"A54","pred":"mondo_id","subj":"T54","obj":"http://purl.obolibrary.org/obo/MONDO_0100096"},{"id":"A55","pred":"mondo_id","subj":"T55","obj":"http://purl.obolibrary.org/obo/MONDO_0100096"},{"id":"A56","pred":"mondo_id","subj":"T56","obj":"http://purl.obolibrary.org/obo/MONDO_0100096"},{"id":"A57","pred":"mondo_id","subj":"T57","obj":"http://purl.obolibrary.org/obo/MONDO_0100096"}],"text":"Exponential growth and detection rate\nThe observed F(x) fit the exponential model of Eq. 4 well with R2 = 0.9778. The estimated α =1.1070, representing the first person who was infected and ignited the epidemic. The estimated β =0.1716, representing the growth rate. Using this estimated growth rate, it takes only 4 days for the diagnosed COVID-19 to double.\nFigure 3 presents the daily detection rates, estimated with the fitted exponential model from day one of the epidemic to the last day of the study period. Based on findings in this figure and data from Figs. 1 and 2, we divided the COVID-19 epidemic during the first two months of the epidemic into five phases.\nFig. 3 Estimated daily detection rate Pi of COVID-19 (2019-nCoV) infection before, during and after declaration of the outbreak, the first 2 months of the Epidemic in China\nPhase 1 was from December 8 to 25, 2019. During this period, the detection rate Pi was high overall, with fluctuations around and above 100%. This was corresponding to the early period after the first suspected case was identified and diagnosed.\nPhase 2 was from December 26, 2019 to January 8, 2020, covering the New Year’s Day. The detection rate Pi fluctuated at around 50% with the lowest of 17% on December 31, 2019 and the highest of 108% on January 8.\nPhase 3 was from January 8 to 20, 2020, and it was featured with a progressive decline in the estimated Pi from 105% on January 8, 2020 to 1% on January 20, 2020. This progressive declining period was the time for the Chinese to prepare for the traditional Chinese New Year’s with the longest and highest level of celebration. Unfortunately, the COVID-19 as an outbreak was silently stepping in during this period.\nPhase 4 was from January 20 to 27, 2020 with the estimated Pi increased from 1% on January 20, 2020 to surpass 100%, and reached the peak of 170% on January 27, 2020. This period was corresponding to the initiation and progressive intensifying of the massive intervention organized and coordinated by the Central Government of China.\nPhase 5 started from January 27, 2020 to the end of the study period, corresponding to the sustained massive national efforts, plus frequent emphases. Different from the previous four phases, reductions in the estimated Pi during this phase were not an indication of under-detection but an indication of declines in the epidemic reflected by the detected and confirmed cases of COVID-19. This is because the model predicted Pi did not consider any interventions but natural growth of the epidemic.\nBased on Figs. 2 and 3 (Phase 4 and 5), three pieces of information can be derived: (1) The epidemic was highly sensitive to external interventions, supporting the nonlinear and chaotic characters revealed by the long latent period in the first three phases; (2) the massive national efforts were highly effective in detecting the detectable COVID-19; (3) signal for the COVID-19 in China to decline appeared on January 21 in 2020, 14 days before the start of eventual declines on February 4, as indicated by F ′  ′ (x) and F ′ (x) in Fig. 2 and Pi in Fig. 3."}

{"project":"LitCovid-PD-CLO","denotations":[{"id":"T81","span":{"begin":1369,"end":1370},"obj":"http://purl.obolibrary.org/obo/CLO_0001020"},{"id":"T82","span":{"begin":1750,"end":1752},"obj":"http://purl.obolibrary.org/obo/CLO_0050509"},{"id":"T83","span":{"begin":1876,"end":1878},"obj":"http://purl.obolibrary.org/obo/CLO_0050509"},{"id":"T84","span":{"begin":1991,"end":2000},"obj":"http://purl.obolibrary.org/obo/OBI_0000245"},{"id":"T85","span":{"begin":2082,"end":2084},"obj":"http://purl.obolibrary.org/obo/CLO_0050509"},{"id":"T86","span":{"begin":2907,"end":2913},"obj":"http://purl.obolibrary.org/obo/SO_0000418"}],"text":"Exponential growth and detection rate\nThe observed F(x) fit the exponential model of Eq. 4 well with R2 = 0.9778. The estimated α =1.1070, representing the first person who was infected and ignited the epidemic. The estimated β =0.1716, representing the growth rate. Using this estimated growth rate, it takes only 4 days for the diagnosed COVID-19 to double.\nFigure 3 presents the daily detection rates, estimated with the fitted exponential model from day one of the epidemic to the last day of the study period. Based on findings in this figure and data from Figs. 1 and 2, we divided the COVID-19 epidemic during the first two months of the epidemic into five phases.\nFig. 3 Estimated daily detection rate Pi of COVID-19 (2019-nCoV) infection before, during and after declaration of the outbreak, the first 2 months of the Epidemic in China\nPhase 1 was from December 8 to 25, 2019. During this period, the detection rate Pi was high overall, with fluctuations around and above 100%. This was corresponding to the early period after the first suspected case was identified and diagnosed.\nPhase 2 was from December 26, 2019 to January 8, 2020, covering the New Year’s Day. The detection rate Pi fluctuated at around 50% with the lowest of 17% on December 31, 2019 and the highest of 108% on January 8.\nPhase 3 was from January 8 to 20, 2020, and it was featured with a progressive decline in the estimated Pi from 105% on January 8, 2020 to 1% on January 20, 2020. This progressive declining period was the time for the Chinese to prepare for the traditional Chinese New Year’s with the longest and highest level of celebration. Unfortunately, the COVID-19 as an outbreak was silently stepping in during this period.\nPhase 4 was from January 20 to 27, 2020 with the estimated Pi increased from 1% on January 20, 2020 to surpass 100%, and reached the peak of 170% on January 27, 2020. This period was corresponding to the initiation and progressive intensifying of the massive intervention organized and coordinated by the Central Government of China.\nPhase 5 started from January 27, 2020 to the end of the study period, corresponding to the sustained massive national efforts, plus frequent emphases. Different from the previous four phases, reductions in the estimated Pi during this phase were not an indication of under-detection but an indication of declines in the epidemic reflected by the detected and confirmed cases of COVID-19. This is because the model predicted Pi did not consider any interventions but natural growth of the epidemic.\nBased on Figs. 2 and 3 (Phase 4 and 5), three pieces of information can be derived: (1) The epidemic was highly sensitive to external interventions, supporting the nonlinear and chaotic characters revealed by the long latent period in the first three phases; (2) the massive national efforts were highly effective in detecting the detectable COVID-19; (3) signal for the COVID-19 in China to decline appeared on January 21 in 2020, 14 days before the start of eventual declines on February 4, as indicated by F ′  ′ (x) and F ′ (x) in Fig. 2 and Pi in Fig. 3."}

{"project":"LitCovid-PD-CHEBI","denotations":[{"id":"T14","span":{"begin":710,"end":712},"obj":"Chemical"},{"id":"T15","span":{"begin":925,"end":927},"obj":"Chemical"},{"id":"T16","span":{"begin":1194,"end":1196},"obj":"Chemical"},{"id":"T17","span":{"begin":1408,"end":1410},"obj":"Chemical"},{"id":"T18","span":{"begin":1778,"end":1780},"obj":"Chemical"},{"id":"T19","span":{"begin":2273,"end":2275},"obj":"Chemical"},{"id":"T20","span":{"begin":2477,"end":2479},"obj":"Chemical"},{"id":"T21","span":{"begin":3097,"end":3099},"obj":"Chemical"}],"attributes":[{"id":"A14","pred":"chebi_id","subj":"T14","obj":"http://purl.obolibrary.org/obo/CHEBI_35780"},{"id":"A15","pred":"chebi_id","subj":"T15","obj":"http://purl.obolibrary.org/obo/CHEBI_35780"},{"id":"A16","pred":"chebi_id","subj":"T16","obj":"http://purl.obolibrary.org/obo/CHEBI_35780"},{"id":"A17","pred":"chebi_id","subj":"T17","obj":"http://purl.obolibrary.org/obo/CHEBI_35780"},{"id":"A18","pred":"chebi_id","subj":"T18","obj":"http://purl.obolibrary.org/obo/CHEBI_35780"},{"id":"A19","pred":"chebi_id","subj":"T19","obj":"http://purl.obolibrary.org/obo/CHEBI_35780"},{"id":"A20","pred":"chebi_id","subj":"T20","obj":"http://purl.obolibrary.org/obo/CHEBI_35780"},{"id":"A21","pred":"chebi_id","subj":"T21","obj":"http://purl.obolibrary.org/obo/CHEBI_35780"}],"text":"Exponential growth and detection rate\nThe observed F(x) fit the exponential model of Eq. 4 well with R2 = 0.9778. The estimated α =1.1070, representing the first person who was infected and ignited the epidemic. The estimated β =0.1716, representing the growth rate. Using this estimated growth rate, it takes only 4 days for the diagnosed COVID-19 to double.\nFigure 3 presents the daily detection rates, estimated with the fitted exponential model from day one of the epidemic to the last day of the study period. Based on findings in this figure and data from Figs. 1 and 2, we divided the COVID-19 epidemic during the first two months of the epidemic into five phases.\nFig. 3 Estimated daily detection rate Pi of COVID-19 (2019-nCoV) infection before, during and after declaration of the outbreak, the first 2 months of the Epidemic in China\nPhase 1 was from December 8 to 25, 2019. During this period, the detection rate Pi was high overall, with fluctuations around and above 100%. This was corresponding to the early period after the first suspected case was identified and diagnosed.\nPhase 2 was from December 26, 2019 to January 8, 2020, covering the New Year’s Day. The detection rate Pi fluctuated at around 50% with the lowest of 17% on December 31, 2019 and the highest of 108% on January 8.\nPhase 3 was from January 8 to 20, 2020, and it was featured with a progressive decline in the estimated Pi from 105% on January 8, 2020 to 1% on January 20, 2020. This progressive declining period was the time for the Chinese to prepare for the traditional Chinese New Year’s with the longest and highest level of celebration. Unfortunately, the COVID-19 as an outbreak was silently stepping in during this period.\nPhase 4 was from January 20 to 27, 2020 with the estimated Pi increased from 1% on January 20, 2020 to surpass 100%, and reached the peak of 170% on January 27, 2020. This period was corresponding to the initiation and progressive intensifying of the massive intervention organized and coordinated by the Central Government of China.\nPhase 5 started from January 27, 2020 to the end of the study period, corresponding to the sustained massive national efforts, plus frequent emphases. Different from the previous four phases, reductions in the estimated Pi during this phase were not an indication of under-detection but an indication of declines in the epidemic reflected by the detected and confirmed cases of COVID-19. This is because the model predicted Pi did not consider any interventions but natural growth of the epidemic.\nBased on Figs. 2 and 3 (Phase 4 and 5), three pieces of information can be derived: (1) The epidemic was highly sensitive to external interventions, supporting the nonlinear and chaotic characters revealed by the long latent period in the first three phases; (2) the massive national efforts were highly effective in detecting the detectable COVID-19; (3) signal for the COVID-19 in China to decline appeared on January 21 in 2020, 14 days before the start of eventual declines on February 4, as indicated by F ′  ′ (x) and F ′ (x) in Fig. 2 and Pi in Fig. 3."}

{"project":"LitCovid-PD-GO-BP","denotations":[{"id":"T3","span":{"begin":12,"end":18},"obj":"http://purl.obolibrary.org/obo/GO_0040007"},{"id":"T4","span":{"begin":254,"end":260},"obj":"http://purl.obolibrary.org/obo/GO_0040007"},{"id":"T5","span":{"begin":288,"end":294},"obj":"http://purl.obolibrary.org/obo/GO_0040007"},{"id":"T6","span":{"begin":2527,"end":2533},"obj":"http://purl.obolibrary.org/obo/GO_0040007"}],"text":"Exponential growth and detection rate\nThe observed F(x) fit the exponential model of Eq. 4 well with R2 = 0.9778. The estimated α =1.1070, representing the first person who was infected and ignited the epidemic. The estimated β =0.1716, representing the growth rate. Using this estimated growth rate, it takes only 4 days for the diagnosed COVID-19 to double.\nFigure 3 presents the daily detection rates, estimated with the fitted exponential model from day one of the epidemic to the last day of the study period. Based on findings in this figure and data from Figs. 1 and 2, we divided the COVID-19 epidemic during the first two months of the epidemic into five phases.\nFig. 3 Estimated daily detection rate Pi of COVID-19 (2019-nCoV) infection before, during and after declaration of the outbreak, the first 2 months of the Epidemic in China\nPhase 1 was from December 8 to 25, 2019. During this period, the detection rate Pi was high overall, with fluctuations around and above 100%. This was corresponding to the early period after the first suspected case was identified and diagnosed.\nPhase 2 was from December 26, 2019 to January 8, 2020, covering the New Year’s Day. The detection rate Pi fluctuated at around 50% with the lowest of 17% on December 31, 2019 and the highest of 108% on January 8.\nPhase 3 was from January 8 to 20, 2020, and it was featured with a progressive decline in the estimated Pi from 105% on January 8, 2020 to 1% on January 20, 2020. This progressive declining period was the time for the Chinese to prepare for the traditional Chinese New Year’s with the longest and highest level of celebration. Unfortunately, the COVID-19 as an outbreak was silently stepping in during this period.\nPhase 4 was from January 20 to 27, 2020 with the estimated Pi increased from 1% on January 20, 2020 to surpass 100%, and reached the peak of 170% on January 27, 2020. This period was corresponding to the initiation and progressive intensifying of the massive intervention organized and coordinated by the Central Government of China.\nPhase 5 started from January 27, 2020 to the end of the study period, corresponding to the sustained massive national efforts, plus frequent emphases. Different from the previous four phases, reductions in the estimated Pi during this phase were not an indication of under-detection but an indication of declines in the epidemic reflected by the detected and confirmed cases of COVID-19. This is because the model predicted Pi did not consider any interventions but natural growth of the epidemic.\nBased on Figs. 2 and 3 (Phase 4 and 5), three pieces of information can be derived: (1) The epidemic was highly sensitive to external interventions, supporting the nonlinear and chaotic characters revealed by the long latent period in the first three phases; (2) the massive national efforts were highly effective in detecting the detectable COVID-19; (3) signal for the COVID-19 in China to decline appeared on January 21 in 2020, 14 days before the start of eventual declines on February 4, as indicated by F ′  ′ (x) and F ′ (x) in Fig. 2 and Pi in Fig. 3."}

{"project":"LitCovid-PD-HP","denotations":[{"id":"T1","span":{"begin":2656,"end":2672},"obj":"Phenotype"}],"attributes":[{"id":"A1","pred":"hp_id","subj":"T1","obj":"http://purl.obolibrary.org/obo/HP_0041092"}],"text":"Exponential growth and detection rate\nThe observed F(x) fit the exponential model of Eq. 4 well with R2 = 0.9778. The estimated α =1.1070, representing the first person who was infected and ignited the epidemic. The estimated β =0.1716, representing the growth rate. Using this estimated growth rate, it takes only 4 days for the diagnosed COVID-19 to double.\nFigure 3 presents the daily detection rates, estimated with the fitted exponential model from day one of the epidemic to the last day of the study period. Based on findings in this figure and data from Figs. 1 and 2, we divided the COVID-19 epidemic during the first two months of the epidemic into five phases.\nFig. 3 Estimated daily detection rate Pi of COVID-19 (2019-nCoV) infection before, during and after declaration of the outbreak, the first 2 months of the Epidemic in China\nPhase 1 was from December 8 to 25, 2019. During this period, the detection rate Pi was high overall, with fluctuations around and above 100%. This was corresponding to the early period after the first suspected case was identified and diagnosed.\nPhase 2 was from December 26, 2019 to January 8, 2020, covering the New Year’s Day. The detection rate Pi fluctuated at around 50% with the lowest of 17% on December 31, 2019 and the highest of 108% on January 8.\nPhase 3 was from January 8 to 20, 2020, and it was featured with a progressive decline in the estimated Pi from 105% on January 8, 2020 to 1% on January 20, 2020. This progressive declining period was the time for the Chinese to prepare for the traditional Chinese New Year’s with the longest and highest level of celebration. Unfortunately, the COVID-19 as an outbreak was silently stepping in during this period.\nPhase 4 was from January 20 to 27, 2020 with the estimated Pi increased from 1% on January 20, 2020 to surpass 100%, and reached the peak of 170% on January 27, 2020. This period was corresponding to the initiation and progressive intensifying of the massive intervention organized and coordinated by the Central Government of China.\nPhase 5 started from January 27, 2020 to the end of the study period, corresponding to the sustained massive national efforts, plus frequent emphases. Different from the previous four phases, reductions in the estimated Pi during this phase were not an indication of under-detection but an indication of declines in the epidemic reflected by the detected and confirmed cases of COVID-19. This is because the model predicted Pi did not consider any interventions but natural growth of the epidemic.\nBased on Figs. 2 and 3 (Phase 4 and 5), three pieces of information can be derived: (1) The epidemic was highly sensitive to external interventions, supporting the nonlinear and chaotic characters revealed by the long latent period in the first three phases; (2) the massive national efforts were highly effective in detecting the detectable COVID-19; (3) signal for the COVID-19 in China to decline appeared on January 21 in 2020, 14 days before the start of eventual declines on February 4, as indicated by F ′  ′ (x) and F ′ (x) in Fig. 2 and Pi in Fig. 3."}

{"project":"LitCovid-sentences","denotations":[{"id":"T119","span":{"begin":0,"end":37},"obj":"Sentence"},{"id":"T120","span":{"begin":38,"end":113},"obj":"Sentence"},{"id":"T121","span":{"begin":114,"end":211},"obj":"Sentence"},{"id":"T122","span":{"begin":212,"end":266},"obj":"Sentence"},{"id":"T123","span":{"begin":267,"end":359},"obj":"Sentence"},{"id":"T124","span":{"begin":360,"end":514},"obj":"Sentence"},{"id":"T125","span":{"begin":515,"end":671},"obj":"Sentence"},{"id":"T126","span":{"begin":672,"end":844},"obj":"Sentence"},{"id":"T127","span":{"begin":845,"end":885},"obj":"Sentence"},{"id":"T128","span":{"begin":886,"end":986},"obj":"Sentence"},{"id":"T129","span":{"begin":987,"end":1090},"obj":"Sentence"},{"id":"T130","span":{"begin":1091,"end":1174},"obj":"Sentence"},{"id":"T131","span":{"begin":1175,"end":1303},"obj":"Sentence"},{"id":"T132","span":{"begin":1304,"end":1466},"obj":"Sentence"},{"id":"T133","span":{"begin":1467,"end":1630},"obj":"Sentence"},{"id":"T134","span":{"begin":1631,"end":1718},"obj":"Sentence"},{"id":"T135","span":{"begin":1719,"end":1885},"obj":"Sentence"},{"id":"T136","span":{"begin":1886,"end":2052},"obj":"Sentence"},{"id":"T137","span":{"begin":2053,"end":2203},"obj":"Sentence"},{"id":"T138","span":{"begin":2204,"end":2440},"obj":"Sentence"},{"id":"T139","span":{"begin":2441,"end":2550},"obj":"Sentence"},{"id":"T140","span":{"begin":2551,"end":2565},"obj":"Sentence"},{"id":"T141","span":{"begin":2566,"end":3110},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"Exponential growth and detection rate\nThe observed F(x) fit the exponential model of Eq. 4 well with R2 = 0.9778. The estimated α =1.1070, representing the first person who was infected and ignited the epidemic. The estimated β =0.1716, representing the growth rate. Using this estimated growth rate, it takes only 4 days for the diagnosed COVID-19 to double.\nFigure 3 presents the daily detection rates, estimated with the fitted exponential model from day one of the epidemic to the last day of the study period. Based on findings in this figure and data from Figs. 1 and 2, we divided the COVID-19 epidemic during the first two months of the epidemic into five phases.\nFig. 3 Estimated daily detection rate Pi of COVID-19 (2019-nCoV) infection before, during and after declaration of the outbreak, the first 2 months of the Epidemic in China\nPhase 1 was from December 8 to 25, 2019. During this period, the detection rate Pi was high overall, with fluctuations around and above 100%. This was corresponding to the early period after the first suspected case was identified and diagnosed.\nPhase 2 was from December 26, 2019 to January 8, 2020, covering the New Year’s Day. The detection rate Pi fluctuated at around 50% with the lowest of 17% on December 31, 2019 and the highest of 108% on January 8.\nPhase 3 was from January 8 to 20, 2020, and it was featured with a progressive decline in the estimated Pi from 105% on January 8, 2020 to 1% on January 20, 2020. This progressive declining period was the time for the Chinese to prepare for the traditional Chinese New Year’s with the longest and highest level of celebration. Unfortunately, the COVID-19 as an outbreak was silently stepping in during this period.\nPhase 4 was from January 20 to 27, 2020 with the estimated Pi increased from 1% on January 20, 2020 to surpass 100%, and reached the peak of 170% on January 27, 2020. This period was corresponding to the initiation and progressive intensifying of the massive intervention organized and coordinated by the Central Government of China.\nPhase 5 started from January 27, 2020 to the end of the study period, corresponding to the sustained massive national efforts, plus frequent emphases. Different from the previous four phases, reductions in the estimated Pi during this phase were not an indication of under-detection but an indication of declines in the epidemic reflected by the detected and confirmed cases of COVID-19. This is because the model predicted Pi did not consider any interventions but natural growth of the epidemic.\nBased on Figs. 2 and 3 (Phase 4 and 5), three pieces of information can be derived: (1) The epidemic was highly sensitive to external interventions, supporting the nonlinear and chaotic characters revealed by the long latent period in the first three phases; (2) the massive national efforts were highly effective in detecting the detectable COVID-19; (3) signal for the COVID-19 in China to decline appeared on January 21 in 2020, 14 days before the start of eventual declines on February 4, as indicated by F ′  ′ (x) and F ′ (x) in Fig. 2 and Pi in Fig. 3."}