Significantly longer Covid-19 incubation times for the elderly, from a case study of 136 patients throughout China

  1. Ally Bi-Zhu Jiang
  2. Richard Lieu
  3. Siobhan Quenby

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Abstract

Objective

To infer Covid-19 incubation time distribution from a large sample.

Method

Based on individual case data published online by 21 cities of China, we investigated a total of 136 COVID-19 patients who traveled to Hubei from 21 cities of China between January 5 and January 31, 2020, remained there for 48 hours or less, and returned to these cities with onset of symptoms between January 10 and February 6, 2020. Among these patients, 110 were found to be aged 15 – 64, 22 aged 65 – 86, and 4 aged under 15.

Findings

The differential incubation time histogram of the two age groups 15 – 64 and 65 – 86 are adequately fitted by the log normal model. For the 15 - 64 age group, the median incubation time of days (uncertainties are 95 −0.90 % CL) is broadly consistent with previous literature. For the 65-86 age group, the median is days is statistically significantly longer. Moreover, for −2.0 this group, the 95 % confidence contour indicates the data cannot constrain the upper bound of the log normal parameters µ, σ by failing to close there; this is because the sample has a maximum incubation time of 17 days, beyond which we ran out of data even though the histogram has not yet peaked. Thus there is the potential of a much longer incubation time for the 65-86 age group than 10 – 14 days. Only a much larger sample can settle this.

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    SciScore for 10.1101/2020.04.14.20065896: (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: An explicit section about the limitations of the techniques employed in this study was not found. We encourage authors to address study limitations.

    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 10.1101/2020.04.14.20065896 on medRxiv