Background
The outbreak of novel coronavirus disease (COVID-19), started from Wuhan, China, at the end of December 2019, hits almost the entire world. In Bangladesh, the first case was officially reported on March 8, 2020. We estimated the basic reproductive number, R0, of COVID-19 for Bangladesh using the first 65-day data of the outbreak.
Methods
With time-varying disease reporting rate, epidemic curves were estimated using the exponential growth model utilizing daily COVID-19 diagnosis data in Bangladesh from March 8 to May 11, 2020. We estimated R0 using the estimated intrinsic growth rate (γ). Serial intervals (SI) have been used from two well-known coronaviruses’ outbreaks, SARS and MERS; and the early estimate of SI of COVID-19 in Wuhan, China.
Results
The COVID-19 epidemic in Bangladesh followed an exponential growth model. We found the R0 to be 1.84 [95% CI: 1.82–1.86], 1.82 [95% CI: 1.81–1.84], and 1.94 [95% CI: 1.92–1.96], for MERS, COVID-19, and SARS SI respectively without adjusting reporting rate. With the adjusted reporting rate, R0 reduced to 1.63 [95% CI: 1.62–1.65], 1.62 [95% CI: 1.61–1.64], and 1.71 [95% CI: 1.70–1.73] for a five-fold increase. Inverse association between the reporting rate and the basic reproduction number was observed.
Conclusion
The R0 was found to be 1.87 for existing cases and was reduced to 1.65 for the five-fold increase of the early reporting rate. Findings suggest a continued COVID-19 outbreak in Bangladesh and immediate steps need to be taken to control.