Paper: Estimation of the reproductive nuber of novel coronavirus and the probable outbreat size on the Diamond Princess cruise ship: A data-driven analysis

Referensi:

Zhang, S., Diao, M., Yu, W., Pei, L., Lin, Z., & Chen, D. (2020). Estimation of the reproductive number of novel coronavirus (COVID-19) and the probable outbreak size on the Diamond Princess cruise ship: A data-driven analysis. International Journal of Infectious Diseases, 93, 201-204.

The reported serial interval (mean and standard deviation) with a gamma distribution and applied “early R” package in R to estimate the R0 in the early stage of COVID-19 outbreak

“Projections” package in R to simulate the plausible cumulative epidemic trajectories and future daily incidence by fitting the data of existing daily incidence, a serial interval distribution, and the estimated R0 into a model based on the assumption that daily incidence obeys approximately Poisson distribution determined by daily infectiousness.

Gap

Because human-to-human transmission of COVID-19 has been confirmed (Huang et al., 2020), and there is limited space and relative high population density on the ship, it is of crucial importance to evaluate the transmissibility of COVID-19, and to forecast the probable size of the epidemic on the Diamond Princess cruise ship in the future

Aim

this study, we estimated the reproductive number (R0) of COVID-19 in the early stage of outbreak on the ship and made a prediction of daily new cases for the next ten days

The Maximum-Likelihood (ML) value of R0 was 2.28 for COVID-19 outbreak at the early stage on the ship. The median with 95% confidence interval (CI) of R0 values was 2.28 (2.06–2.52) estimated by the bootstrap resampling method

The probable number of new cases for the next ten days would gradually increase, and the estimated cumulative cases would reach 1514 (1384–1656) at the tenth day in the future. 

However, if R0 value was reduced by 25% and 50%, the estimated total number of cumulative cases would be reduced to 1081 (981–1177) and 758 (697–817), respectively.

The median with 95% CI of R0 of COVID-19 was about 2.28 (2.06–2.52) during the early stage experienced on the Diamond Princess cruise ship. The future daily incidence and probable outbreak size is largely dependent on the change of R0. Unless strict infection management and control are taken, our findings indicate the potential of COVID-19 to cause greater outbreak on the ship.

If the R0 value remained unchanged, the cumulative number of infected cases may reach 1514 at the tenth day, suggesting more than forty percent of the population would be infected[1]. Fortunately, the crew has taken more stringent measures to control the spread of infection. As a result, the transmissibility is expected to be reduced in the coming days

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