Estimation of Effective Reproduction Number for COVID-19 in Bangladesh and its districts

Abstract

Background Bangladesh is going through an unprecedented crisis since the onset of the COVID-19 pandemic. Throughout the COVID-19 pandemic, the reproduction number of COVID-19 swarmed in the scientific community and public media due to its simplicity in explaining an infectious disease dynamic. This paper aims to estimate the effective reproduction number (Rt) for COVID-19 over time in Bangladesh and its districts using reported cases. Methods Adapted methods derived from Bettencourt and Ribeiro (2008), which is a sequential Bayesian approach using the compartmental Susceptible-Infectious-Recovered (SIR) model, have been used to estimate Rt. Findings As of July 21, the mean Rt is 1.32(0.98-1.70, 90% HDI), with a median of 1.16(0.99-1.34 90% HDI). The initial Rt of Bangladesh was 3, whereas the Rt on the day of imposing nation-wide lockdown was 1.47, at the end of lockdown phase 1 was 1.06, at the end of lockdown phase 2 was 1.33. Each phase of nation-wide lockdown has contributed to the decline of effective reproduction number (Rt) for Bangladesh by 28.44%, and 26.70%, respectively, implying moderate effectiveness of the epidemic response strategies. Interpretation and Conclusion The mean Rt fell by 13.55% from May 31 to July 21, 2020, despite easing of lockdown in Bangladesh. The Rt continued to fall below the threshold value one steadily from the beginning of July and sustained around 1. The mean Rt fell by 13.55% from May 31 to July 21, 2020, despite easing of lockdown in Bangladesh. As of July 21, the current estimate of Rt is 1.07(0.92-1.15: 90% HDI), meaning that an infected individual is spreading the virus to an average of one other, with 0.07 added chance of infecting a second individual. This whole research recommends two things- broader testing and careful calibration of measures to keep Rt a long way below the crucial threshold one.

Promoting Statistical Practice and Collaboration in Developing Countries

“…The estimate showed that as of May 7th, 2020, Nigeria needs to re-evaluate their control measures as R t was above one. The Bangladesh estimate also shows a similar pattern [70]. For this approach, we let L(t) be locally acquired infections and λ(t) be the rate of infection.…”

“…We present below the R-syntax for computing and plotting the marginal posterior probabilities of 𝜃 and finding its 95% HPD intervals. (70,190, 0.01) # set possible range of theta tau = seq(0.0001, 1, 0.01) # set possible range of tau # 2D lattice of theta and tau par1 = matrix(theta,length(theta),length(tau)) par2 = matrix(tau, length(theta),length(tau)) log_prior = -log(par2) # log prior density…”

“…The plots of the numerically obtained marginal posterior density of 𝜃 given 𝑥 and of the predictive posterior density of X new given x are shown in Figure 18.4. (70,190 Given the IQs of 40 women of age-group 20-25, which range from 101 to 154, and an assumed noninformative prior density over the average IQ of women, its posterior density is symmetric with a peak around 125. The average IQ of women, approximately, lies within 120 to 129 with a 95% chance.…”

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“…To measure the transmission of COVID-19, many studies used a reproduction number of the coronavirus as an indicator of the disease's ability to spread in both the early phase and the real-time [7][8][9][10][11][12][13][14][15][16]. A basic reproduction number (R 0 ) is an indicator whether a disease will become an outbreak or not [9].…”

A cross-sectional pilot study on COVID-19 disease pattern, recovery status and effect of co-morbidities in Bangladesh

“…Bangladesh has been battling with this disease since 8th March 2020 when the first 3 cases were reported and since then COVID-19 has spread in almost all the districts resulting in a nationwide lockdown from the 17 th March which has not yet been completely lifted (Hridoy et al, 2020b). As of 21st July 2020, the mean reproduction number of SARS-CoV-2 in Bangladesh is 1.32 (Hridoy et al, 2020a) and as of 31st August 2020, there have officially been 312,996 cases and 4,281 deaths due to COVID-19 in this country (Bangladesh Coronavirus-Worldometer, 2020). With the existing health policy and structures, battling COVID-19 has been a mammoth task for Bangladesh and people are still facing obstacles to ensure appropriate treatment for themselves (Khan et al, 2020;Shammi et al, 2020).…”