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  1. Article ; Online: Systematic comparison of epidemic growth patterns using two different estimation approaches.

    Lee, Yiseul / Roosa, Kimberlyn / Chowell, Gerardo

    Infectious Disease Modelling

    2020  Volume 6, Page(s) 5–14

    Abstract: Background: Different estimation approaches are frequently used to calibrate mathematical models to epidemiological data, particularly for analyzing infectious disease outbreaks. Here, we use two common methods to estimate parameters that characterize ... ...

    Abstract Background: Different estimation approaches are frequently used to calibrate mathematical models to epidemiological data, particularly for analyzing infectious disease outbreaks. Here, we use two common methods to estimate parameters that characterize growth patterns using the generalized growth model (GGM) calibrated to real outbreak datasets.
    Materials and methods: Data from 31 outbreaks are used to fit the GGM to the ascending phase of each outbreak and estimate the parameters using both least squares (LSQ) and maximum likelihood estimation (MLE) methods. We utilize parametric bootstrapping to construct confidence intervals for parameter estimates. We compare the results including RMSE, Anscombe residual, and 95% prediction interval coverage. We also evaluate the correlation between the estimates from both methods.
    Results: Comparing LSQ and MLE estimates, most outbreaks have similar parameter estimates, RMSE, Anscombe, and 95% prediction interval coverage. Parameter estimates do not differ across methods when the model yields a good fit to the early growth phase. However, for two outbreaks, there are systematic deviations in model fit to the data that explain differences in parameter estimates (e.g., residuals represent random error rather than systematic deviation).
    Conclusion: Our findings indicate that utilizing LSQ and MLE methods produce similar results in the context of characterizing epidemic growth patterns with the GGM, provided that the model yields a good fit to the data.
    Language English
    Publishing date 2020-10-24
    Publishing country China
    Document type Journal Article
    ZDB-ID 3015225-2
    ISSN 2468-0427 ; 2468-2152
    ISSN (online) 2468-0427
    ISSN 2468-2152
    DOI 10.1016/j.idm.2020.10.005
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Transmission potential and severity of COVID-19 in South Korea.

    Shim, Eunha / Tariq, Amna / Choi, Wongyeong / Lee, Yiseul / Chowell, Gerardo

    International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases

    2020  Volume 93, Page(s) 339–344

    Abstract: Objectives: Since the first case of 2019 novel coronavirus (COVID-19) identified on Jan 20, 2020, in South Korea, the number of cases rapidly increased, resulting in 6284 cases including 42 deaths as of Mar 6, 2020. To examine the growth rate of the ... ...

    Abstract Objectives: Since the first case of 2019 novel coronavirus (COVID-19) identified on Jan 20, 2020, in South Korea, the number of cases rapidly increased, resulting in 6284 cases including 42 deaths as of Mar 6, 2020. To examine the growth rate of the outbreak, we present the first study to report the reproduction number of COVID-19 in South Korea.
    Methods: The daily confirmed cases of COVID-19 in South Korea were extracted from publicly available sources. By using the empirical reporting delay distribution and simulating the generalized growth model, we estimated the effective reproduction number based on the discretized probability distribution of the generation interval.
    Results: We identified four major clusters and estimated the reproduction number at 1.5 (95% CI: 1.4-1.6). In addition, the intrinsic growth rate was estimated at 0.6 (95% CI: 0.6, 0.7), and the scaling of growth parameter was estimated at 0.8 (95% CI: 0.7, 0.8), indicating sub-exponential growth dynamics of COVID-19. The crude case fatality rate is higher among males (1.1%) compared to females (0.4%) and increases with older age.
    Conclusions: Our results indicate an early sustained transmission of COVID-19 in South Korea and support the implementation of social distancing measures to rapidly control the outbreak.
    MeSH term(s) Age Factors ; Betacoronavirus/pathogenicity ; COVID-19 ; Coronavirus Infections/epidemiology ; Coronavirus Infections/mortality ; Coronavirus Infections/prevention & control ; Coronavirus Infections/transmission ; Female ; Humans ; Male ; Models, Statistical ; Pandemics/prevention & control ; Pandemics/statistics & numerical data ; Pneumonia, Viral/epidemiology ; Pneumonia, Viral/mortality ; Pneumonia, Viral/prevention & control ; Pneumonia, Viral/transmission ; Republic of Korea/epidemiology ; SARS-CoV-2 ; Sex Factors
    Keywords covid19
    Language English
    Publishing date 2020-03-18
    Publishing country Canada
    Document type Journal Article
    ZDB-ID 1331197-9
    ISSN 1878-3511 ; 1201-9712
    ISSN (online) 1878-3511
    ISSN 1201-9712
    DOI 10.1016/j.ijid.2020.03.031
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Real-time monitoring the transmission potential of COVID-19 in Singapore, March 2020.

    Tariq, Amna / Lee, Yiseul / Roosa, Kimberlyn / Blumberg, Seth / Yan, Ping / Ma, Stefan / Chowell, Gerardo

    BMC medicine

    2020  Volume 18, Issue 1, Page(s) 166

    Abstract: Background: As of March 31, 2020, the ongoing COVID-19 epidemic that started in China in December 2019 is now generating local transmission around the world. The geographic heterogeneity and associated intervention strategies highlight the need to ... ...

    Abstract Background: As of March 31, 2020, the ongoing COVID-19 epidemic that started in China in December 2019 is now generating local transmission around the world. The geographic heterogeneity and associated intervention strategies highlight the need to monitor in real time the transmission potential of COVID-19. Singapore provides a unique case example for monitoring transmission, as there have been multiple disease clusters, yet transmission remains relatively continued.
    Methods: Here we estimate the effective reproduction number, R
    Results: The local incidence curve displays sub-exponential growth dynamics, with the reproduction number following a declining trend and reaching an estimate at 0.7 (95% CI 0.3, 1.0) during the first transmission wave by February 14, 2020, while the overall R based on the cluster size distribution as of March 17, 2020, was estimated at 0.6 (95% CI 0.4, 1.02). The overall mean reporting delay was estimated at 6.4 days (95% CI 5.8, 6.9), but it was shorter among imported cases compared to local cases (mean 4.3 vs. 7.6 days, Wilcoxon test, p < 0.001).
    Conclusion: The trajectory of the reproduction number in Singapore underscores the significant effects of successful containment efforts in Singapore, but it also suggests the need to sustain social distancing and active case finding efforts to stomp out all active chains of transmission.
    MeSH term(s) Betacoronavirus ; COVID-19 ; Coronavirus Infections/epidemiology ; Coronavirus Infections/transmission ; Humans ; Pandemics ; Pneumonia, Viral/epidemiology ; Pneumonia, Viral/transmission ; SARS-CoV-2 ; Singapore/epidemiology
    Keywords covid19
    Language English
    Publishing date 2020-06-03
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2131669-7
    ISSN 1741-7015 ; 1741-7015
    ISSN (online) 1741-7015
    ISSN 1741-7015
    DOI 10.1186/s12916-020-01615-9
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Real-time monitoring the transmission potential of COVID-19 in Singapore, March 2020.

    Tariq, Amna / Lee, Yiseul / Roosa, Kimberlyn / Blumberg, Seth / Yan, Ping / Ma, Stefan / Chowell, Gerardo

    medRxiv : the preprint server for health sciences

    2020  

    Abstract: Background: As of March 31, 2020 the ongoing COVID-19 epidemic that started in China in December 2019 is now generating local transmission around the world. The geographic heterogeneity and associated intervention strategies highlight the need to ... ...

    Abstract Background: As of March 31, 2020 the ongoing COVID-19 epidemic that started in China in December 2019 is now generating local transmission around the world. The geographic heterogeneity and associated intervention strategies highlight the need to monitor in real time the transmission potential of COVID-19. Singapore provides a unique case example for monitoring transmission, as there have been multiple disease clusters, yet transmission remains relatively continued.
    Methods: Here we estimate the effective reproduction number, R
    Results: The local incidence curve displays sub-exponential growth dynamics, with the reproduction number following a declining trend and reaching an estimate at 0.7 (95% CI: 0.3, 1.0) during the first transmission wave by February 14, 2020 while the overall R based on the cluster size distribution as of March 17, 2020 was estimated at 0.6 (95% CI: 0.4, 1.02). The overall mean reporting delay was estimated at 6.4 days (95% CI: 5.8, 6.9), but it was shorter among imported cases compared to local cases (mean 4.3 vs. 7.6 days, Wilcoxon test, p<0.001).
    Conclusion: The trajectory of the reproduction number in Singapore underscores the significant effects of successful containment efforts in Singapore, but it also suggests the need to sustain social distancing and active case finding efforts to stomp out all active chains of transmission.
    Keywords covid19
    Language English
    Publishing date 2020-04-17
    Publishing country United States
    Document type Preprint
    DOI 10.1101/2020.02.21.20026435
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Transmission potential and severity of COVID-19 in South Korea

    Shim, Eunha / Tariq, Amna / Choi, Wongyeong / Lee, Yiseul / Chowell, Gerardo

    Int J Infect Dis

    Abstract: OBJECTIVES: Since the first case of 2019 novel coronavirus (COVID-19) identified on Jan 20, 2020, in South Korea, the number of cases rapidly increased, resulting in 6284 cases including 42 deaths as of Mar 6, 2020. To examine the growth rate of the ... ...

    Abstract OBJECTIVES: Since the first case of 2019 novel coronavirus (COVID-19) identified on Jan 20, 2020, in South Korea, the number of cases rapidly increased, resulting in 6284 cases including 42 deaths as of Mar 6, 2020. To examine the growth rate of the outbreak, we present the first study to report the reproduction number of COVID-19 in South Korea. METHODS: The daily confirmed cases of COVID-19 in South Korea were extracted from publicly available sources. By using the empirical reporting delay distribution and simulating the generalized growth model, we estimated the effective reproduction number based on the discretized probability distribution of the generation interval. RESULTS: We identified four major clusters and estimated the reproduction number at 1.5 (95% CI: 1.4-1.6). In addition, the intrinsic growth rate was estimated at 0.6 (95% CI: 0.6, 0.7), and the scaling of growth parameter was estimated at 0.8 (95% CI: 0.7, 0.8), indicating sub-exponential growth dynamics of COVID-19. The crude case fatality rate is higher among males (1.1%) compared to females (0.4%) and increases with older age. CONCLUSIONS: Our results indicate an early sustained transmission of COVID-19 in South Korea and support the implementation of social distancing measures to rapidly control the outbreak.
    Keywords covid19
    Publisher WHO
    Document type Article
    Note WHO #Covidence: #8876
    Database COVID19

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  6. Article ; Online: Transmission potential of COVID-19 in South Korea

    Shim, Eunha / Tariq, Amna / Choi, Wongyeong / Lee, Yiseul / Chowell, Gerardo

    Abstract: Since the first identified individual of 2019 novel coronavirus (COVID-19) infection on Jan 20, 2020 in South Korea, the number of confirmed cases rapidly increased. As of Feb 26, 2020, 1,261 cases of COVID-19 including 12 deaths were confirmed in South ... ...

    Abstract Since the first identified individual of 2019 novel coronavirus (COVID-19) infection on Jan 20, 2020 in South Korea, the number of confirmed cases rapidly increased. As of Feb 26, 2020, 1,261 cases of COVID-19 including 12 deaths were confirmed in South Korea. Using the incidence data of COVID-19, we estimate the reproduction number at 1.5 (95% CI: 1.4-1.6), which indicates sustained transmission and support the implementation of social distancing measures to rapidly control the outbreak.
    Keywords covid19
    Publisher MedRxiv; WHO
    Document type Article ; Online
    DOI 10.1101/2020.02.27.20028829
    Database COVID19

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  7. Article ; Online: Transmission potential of COVID-19 in South Korea

    Shim, Eunha / Tariq, Amna / Choi, Wongyeong / Lee, Yiseul / Chowell, Gerardo

    medRxiv

    Abstract: Since the first identified individual of 2019 novel coronavirus (COVID-19) infection on Jan 20, 2020 in South Korea, the number of confirmed cases rapidly increased. As of Feb 26, 2020, 1,261 cases of COVID-19 including 12 deaths were confirmed in South ... ...

    Abstract Since the first identified individual of 2019 novel coronavirus (COVID-19) infection on Jan 20, 2020 in South Korea, the number of confirmed cases rapidly increased. As of Feb 26, 2020, 1,261 cases of COVID-19 including 12 deaths were confirmed in South Korea. Using the incidence data of COVID-19, we estimate the reproduction number at 1.5 (95% CI: 1.4-1.6), which indicates sustained transmission and support the implementation of social distancing measures to rapidly control the outbreak.
    Keywords covid19
    Language English
    Publishing date 2020-03-02
    Publisher Cold Spring Harbor Laboratory Press
    Document type Article ; Online
    DOI 10.1101/2020.02.27.20028829
    Database COVID19

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  8. Article ; Online: Transmission potential and severity of COVID-19 in South Korea

    Shim, Eunha / Tariq, Amna / Choi, Wongyeong / Lee, Yiseul / Chowell, Gerardo

    International journal of infectious diseases, 93:339-344

    2020  

    Abstract: OBJECTIVES: Since the first case of 2019 novel coronavirus (COVID-19) identified on Jan 20, 2020, in South Korea, the number of cases rapidly increased, resulting in 6284 cases including 42 deaths as of Mar 6, 2020. To examine the growth rate of the ... ...

    Abstract OBJECTIVES: Since the first case of 2019 novel coronavirus (COVID-19) identified on Jan 20, 2020, in South Korea, the number of cases rapidly increased, resulting in 6284 cases including 42 deaths as of Mar 6, 2020. To examine the growth rate of the outbreak, we present the first study to report the reproduction number of COVID-19 in South Korea. METHODS: The daily confirmed cases of COVID-19 in South Korea were extracted from publicly available sources. By using the empirical reporting delay distribution and simulating the generalized growth model, we estimated the effective reproduction number based on the discretized probability distribution of the generation interval. RESULTS: We identified four major clusters and estimated the reproduction number at 1.5 (95% CI: 1.4–1.6). In addition, the intrinsic growth rate was estimated at 0.6 (95% CI: 0.6, 0.7), and the scaling of growth parameter was estimated at 0.8 (95% CI: 0.7, 0.8), indicating sub-exponential growth dynamics of COVID-19. The crude case fatality rate is higher among males (1.1%) compared to females (0.4%) and increases with older age. CONCLUSIONS: Our results indicate an early sustained transmission of COVID-19 in South Korea and support the implementation of social distancing measures to rapidly control the outbreak.
    Keywords COVID-19 ; Reproduction number ; Coronavirus ; Korea ; covid19
    Language English
    Publishing country de
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  9. Article ; Online: Transmission potential and severity of COVID-19 in South Korea

    Shim, Eunha / Tariq, Amna / Choi, Wongyeong / Lee, Yiseul / Chowell, Gerardo

    International Journal of Infectious Diseases

    2020  Volume 93, Page(s) 339–344

    Keywords Microbiology (medical) ; Infectious Diseases ; General Medicine ; covid19
    Language English
    Publisher Elsevier BV
    Publishing country us
    Document type Article ; Online
    ZDB-ID 1331197-9
    ISSN 1878-3511 ; 1201-9712
    ISSN (online) 1878-3511
    ISSN 1201-9712
    DOI 10.1016/j.ijid.2020.03.031
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: Severe Acute Respiratory Syndrome Coronavirus 2 Transmission Potential, Iran, 2020.

    Muniz-Rodriguez, Kamalich / Fung, Isaac Chun-Hai / Ferdosi, Shayesteh R / Ofori, Sylvia K / Lee, Yiseul / Tariq, Amna / Chowell, Gerardo

    Emerging infectious diseases

    2020  Volume 26, Issue 8, Page(s) 1915–1917

    Abstract: To determine the transmission potential of severe acute respiratory syndrome coronavirus 2 in Iran in 2020, we estimated the reproduction number as 4.4 (95% CI 3.9-4.9) by using a generalized growth model and 3.5 (95% CI 1.3-8.1) by using epidemic ... ...

    Abstract To determine the transmission potential of severe acute respiratory syndrome coronavirus 2 in Iran in 2020, we estimated the reproduction number as 4.4 (95% CI 3.9-4.9) by using a generalized growth model and 3.5 (95% CI 1.3-8.1) by using epidemic doubling time. The reproduction number decreased to 1.55 after social distancing interventions were implemented.
    MeSH term(s) Betacoronavirus/growth & development ; Betacoronavirus/pathogenicity ; COVID-19 ; COVID-19 Testing ; Clinical Laboratory Techniques/methods ; Communicable Disease Control/methods ; Communicable Disease Control/organization & administration ; Coronavirus Infections/diagnosis ; Coronavirus Infections/epidemiology ; Coronavirus Infections/prevention & control ; Coronavirus Infections/transmission ; Humans ; Incidence ; Iran/epidemiology ; Models, Statistical ; Pandemics/prevention & control ; Physical Distancing ; Pneumonia, Viral/diagnosis ; Pneumonia, Viral/epidemiology ; Pneumonia, Viral/prevention & control ; Pneumonia, Viral/transmission ; SARS-CoV-2 ; Time Factors
    Keywords covid19
    Language English
    Publishing date 2020-04-22
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 1380686-5
    ISSN 1080-6059 ; 1080-6040
    ISSN (online) 1080-6059
    ISSN 1080-6040
    DOI 10.3201/eid2608.200536
    Database MEDical Literature Analysis and Retrieval System OnLINE

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