The basic reproduction number and prediction of the epidemic size of the novel coronavirus (COVID-19) in Shahroud, Iran

  1. Ahmad Khosravi
  2. Reza Chaman
  3. Marzieh Rohani-Rasaf
  4. Fariba Zare
  5. Shiva Mehravaran
  6. Mohammad Hassan Emamian

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Abstract

Objectives

To estimate the basic reproduction number (R 0 ) of COVID-19 in the early stage of the epidemic and predict the expected number of new cases in Shahroud, Northeast of Iran.

Methods

The R 0 of COVID-19 was estimated using the serial interval distribution and the number of incidence cases. The serial interval was fit with a gamma distribution. The probable incidence and cumulative incidence in the next 30 days were predicted using the assumption that daily incidence follows a Poisson distribution determined by daily infectiousness. Data analysis was done using “earlyR” and “projections” packages in R software.

Results

The maximum-likelihood value of R 0 was 2.7 (95% confidence interval (CI): 2.1 to 3.4) for the COVID-19 epidemic in the early 14 days and decreased to 1.13 (95% CI: 1.03 to 1.25) by the end of the day 41. The expected average number of new cases in Shahroud is 9.0±3.8 case/day, which means an estimated total of 271 (95% CI: 178-383) new cases in the next 30 days.

Conclusions

It is essential to reduce the R 0 to values below one. Therefore, we strongly recommend enforcing and continuing the current preventive measures, restricting travel, and providing screening tests for a larger proportion of the population.

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  1. ScreenIT

    SciScore for 10.1101/2020.04.04.20052308: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementIRB: The protocol of this study was reviewed and approved by the Institutional Review Board of Shahroud University of Medical Science (IR.SHMU.REC.1398.160).
    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:
    It also emphasizes the need for these measures to be continued along with stricter limitations in transportation until the transmission chain is broken and the epidemic is successfully controlled. The main strengths of this study include its careful design, taking throat and nasopharyngeal swabs for testing of all suspected cases, and systematic recording of positive cases. Limitation were that testing was only done for those admitted into the hospital, as well as potential limitations in the calculation of R0, In conclusion, the R0 of COVID-19 in Shahroud was considerably high at the onset of the epidemic, but with preventive measures and public education, it has been reduced to 1.13 (95% CI: 1.03-1.25) within 41 days. This reduction highlights the success of preventive measures in place, but we must be prepared for the doubling of cases over the next month. We strongly recommend performing mass screening of suspected cases, implementing travel restrictions especially during Spring holidays, and expanding coronavirus testing to the community. After the ending the holidays, longer and stronger limitations needed.

    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.

    About SciScore

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  2. Version published to 10.1101/2020.04.04.20052308v1 on medRxiv
  3. Version published to 10.1017/s0950268820001247