Real-Time Estimation of the Risk of Death from Novel Coronavirus (COVID-19) Infection: Inference Using Exported Cases

  1. Sung-mok Jung
  2. Andrei R. Akhmetzhanov
  3. Katsuma Hayashi
  4. Natalie M. Linton
  5. Yichi Yang
  6. Baoyin Yuan
  7. Tetsuro Kobayashi
  8. Ryo Kinoshita
  9. Hiroshi Nishiura

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Abstract

The exported cases of 2019 novel coronavirus (COVID-19) infection that were confirmed outside of China provide an opportunity to estimate the cumulative incidence and confirmed case fatality risk (cCFR) in mainland China. Knowledge of the cCFR is critical to characterize the severity and understand the pandemic potential of COVID-19 in the early stage of the epidemic. Using the exponential growth rate of the incidence, the present study statistically estimated the cCFR and the basic reproduction number—the average number of secondary cases generated by a single primary case in a naïve population. We modeled epidemic growth either from a single index case with illness onset on 8 December, 2019 (Scenario 1), or using the growth rate fitted along with the other parameters (Scenario 2) based on data from 20 exported cases reported by 24 January, 2020. The cumulative incidence in China by 24 January was estimated at 6924 cases (95% CI: 4885, 9211) and 19,289 cases (95% CI: 10,901, 30,158), respectively. The latest estimated values of the cCFR were 5.3% (95% CI: 3.5%, 7.5%) for Scenario 1 and 8.4% (95% CI: 5.3%, 12.3%) for Scenario 2. The basic reproduction number was estimated to be 2.1 (95% CI: 2.0, 2.2) and 3.2 (95% CI: 2.7, 3.7) for Scenarios 1 and 2, respectively. Based on these results, we argued that the current COVID-19 epidemic has a substantial potential for causing a pandemic. The proposed approach provides insights in early risk assessment using publicly available data.

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  1. ScreenIT

    SciScore for 10.1101/2020.01.29.20019547: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    No key resources detected.

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    There are five main limitations in the present study. First, our results present an estimate for the cCFR which only addresses fatality among confirmed cases. More precise IFR estimate that includes infected individuals other than confirmed cases can only be estimated using additional pieces of data (e.g., seroepidemiological data or outpatient clinic visits). It should be noted that not only the denominator but also numerator values are also subject for better estimation (e.g. excess mortality estimate). Second, our study relied on limited empirical data that were extracted from publicly available data sources. Thus, future studies with greater sample size and precision are needed. Nonetheless, we believe that this study will improve the situational assessment of the ongoing epidemic. Third, our assumed date of illness onset for the index case in Scenario 1 is based on initial reports of the earliest onset date for a case, and the continued exponential growth with the rate r is the authors’ extrapolation. However, we conducted a sensitivity analysis and ensured that the resulting statistical estimates would not greatly vary from our main results. Fourth, there is an uncertainty in the detection window time T. Since the epidemiological investigations are being actively implemented outside China, we believe that the sum of the incubation period and the infectious period can be a plausible estimation of the detection time window. Fifth, heterogeneous aspects of death (e.g. age ...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

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  2. Version published to 10.1101/2020.01.29.20019547v2 on medRxiv
  3. Version published to 10.3390/jcm9020523
  4. Version published to 10.1101/2020.01.29.20019547v1 on medRxiv