key: cord-1032250-6fq8lluy
authors: Siam, Z. S.; Arifuzzaman, M.; Rashid, M. H.; islam, m. s.
title: No lockdown policy for COVID-19 epidemic in Bangladesh: Good, bad or ugly?
date: 2020-10-23
journal: nan
DOI: 10.1101/2020.10.21.20216812
sha: 34a96a942be9c5e7cc9c614d56057940e2d2408d
doc_id: 1032250
cord_uid: 6fq8lluy

Bangladesh has been combating the COVID-19 pandemic with limited financial resources and poor health infrastructure since March, 2020. Although the government has imposed several restricted measures to curb the progression of the outbreak, these arrays of measures are not sustainable in the long run. In this study, we assess the impact of lift of flexible lockdown on the COVID-19 dynamics in Bangladesh. Our analysis demonstrates that the country might experience second infection peak in 6-7 months after the withdrawal of current lockdown. Moreover, a prolonged restriction until January, 2021 will shift the infection peak towards August, 2021 and will reduce approximately 20 % COVID-19 cases in Bangladesh.

COVID-19 has emerged as one of the most challenging infectious diseases in the World's history. 1 , 2 Initially, China, several countries of Europe and America were severely affected by COVID-19, but recently the virus has spread in South-Asian countries including, India, Pakistan, and Bangladesh. Although several studies demonstrate the importance of imposing lockdown to slow down the progression of the pandemic 3, 4 , a lockdown cannot last indefinitely as it has a negative impact on national economies as well as people's goodwill. As a result, despite the significant amount of COVID-19 positive cases under restricted conditions, Government has lifted the lockdown gradually by reopening all the industries, markets and offices with a notable exception of educational institutes. Notably, the age group (in years) of 1-20 carries 43.5 % of total age distribution of the population in Bangladesh (collected from Socioeconomic Data and Application Center, or SEDAC). Moreover, Hoque and colleagues recently reported that only 10.2 % of the total COVID-19 positive cases were identified within the age group of 1-20 compared 54.6 % cases from the age group of 21-40. 5 Since all the academic institutes are closed to contain COVID-19 diffusion, one might ask whether Bangladesh is going through a flexible lockdown and if so, then what could be the consequences on the public health when the flexible lockdown is lifted in the upcoming months. Besides, it is important to have a trade-off between various key epidemiological factors to predict the COVID-19 transmission in Bangladesh and that is where a mathematical estimation becomes relevant to evaluate the future we may expect based on the latest policies implemented in the country. Here, we use the epidemiological model to explore the consequences of 'No lockdown' policy on the future trend of COVID-19 cases in Bangladesh so that policymaker can take right decisions considering the socioeconomic structure of the country.

SEIRD model is used to forecast the dynamics of the pandemic in Bangladesh. The model has five time dependent important variables: S, E, I, R, and D. 6 The terms S(t), E(t), I(t), R(t) and D(t) denote the susceptible population, exposed people, infected population, recovered people and the death individuals respectively.

The total population at time t: ( ) = ( ) + ( ) + ( ) + ( ) + ( ).

. CC-BY-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

The copyright holder for this preprint this version posted October 23, 2020. ; https://doi.org/10.1101/2020.10.21.20216812 doi: medRxiv preprint A set of ordinary differential equations is used (see the supplement) to describe the SEIRD model as shown previously. 6 The basic reproduction number (R0) plays a key role to identify whether an infectious disease becomes epidemic (R0 > 1) or not (R0 < 1) in any epidemiological analyses. Therefore, the epidemic control methods are executed to stop the outbreak when R0 > 1. 7 The timedependent reproduction number, Rt, determines the transmission speed of the pandemic. In this study, we set the value of basic reproduction number, R0 ~2.5.

A set of differential equations that describes the SEIRD model

The parameters , and µ represent the transmission rate, recovery rate and death rate respectively. The symbol σ stands for the fraction of the rate of transfer of disease from latent to the infectious stage.

In our study, we selected the following initial conditions: E(0) = 10, I(0) = 40, R(0) = 0 and D(0) = 0. To take the correct susceptible population is very important to model any pandemic where the entire population can be chosen as susceptible population. Several studies reported an estimation of susceptible by multiplying 10 -3 -10 -5 with the total population of the country based on Germany, South Korea and China's COVID-19 outbreak. 4 In this note, S(0) ~ N * 10 -1 (17 million) has been taken as it provides the best fit with real data. Moreover, E(0) = 10 was set in the analysis as it would allow the disease to spread at a moderate rate. We tested several values of E(0) (not shown . CC-BY-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted October 23, 2020. ; https://doi.org/10.1101/2020.10.21.20216812 doi: medRxiv preprint in the manuscript) and the value of 10 gives the best fit. The value of transmission rate, = 0.12 was set for the analysis, whereas recovery rate, γ = 0.038 day -1 was considered which corresponds to ~ 26 days. The value of death rate, µ, was taken as 0.0008.

Imposing restricted array of measures can have positive impacts on the COVID-19 outbreak, 3 (Fig. 1A) , with a daily death toll going as high as 200 deaths (Fig. 1B) . Moreover, Bangladesh might face the dire consequences by then as approximately 85000 citizens could die due to the COVID-19 outbreak. We further explore the probable fate of coronavirus affected Bangladesh if the nation exits lockdown from November, 2020. In that case, the present epidemiological model forecasts the reappearance of infection peak (~370000 active cases) in the third week of July, 2021 with ~75000 deaths associated with coronavirus. Notably, prolonging the current flexible lockdown until January, 2021 or withdrawing the restrictions in January, 2021, will further shift the infection peak to the middle of September, 2021 (Fig. 1A) . In that case, the SEIRD model predicts a total infected number ~330000 and death toll of 70000 in the third week of September, 2021 (Fig. 1B) . Therefore, this study exclusively preditcs COVID-19 pandemic situation in Bangladesh, given the potential for lift of lockdown at different time points before the outbreak ends.

. CC-BY-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted October 23, 2020. ; https://doi.org/10.1101/2020.10.21.20216812 doi: medRxiv preprint To estimate the dire consequences due to the current pandemic, next we assume a gradual increase the Rt values from 0.96 to 1.5 in no restricted conditions. Similar to our first study, no lockdown from October, 2020 results the next infection peak with ~820000 corona positive cases on May, 2021. Moreover, if the Government extend the flexible lockdown until January, 2021, the infection peak will touch approximately 750000 cases along with ~110000 deaths on August, 2021. Moreover, we also make further speculation based on the Rt values (0.96 ≤ Rt ≤ 2) in no lockdown environment (Supplement Fig. 1) in Bangladesh.

. CC-BY-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted October 23, 2020. ; https://doi.org/10.1101/2020.10.21.20216812 doi: medRxiv preprint 

Several reports showed the major role of lockdown to slow down the spread of COVID-19 and in response, the Bangladesh government has set up various strict measures to keep the rising of outbreak under control. 6, 8 However, as a middle-income country, Bangladesh might not sustain being restricted in the long run by imposing prolonged lockdown. Hence, in this study, we forecast the expected consequences of the lift of lockdown and show 'no lockdown' policies could be jeopardized as it skyrockets the number of COVID-19 positive cases and the death toll in Bangladesh. Our epidemiological model further predicts about a gigantic infection peak with enormous death tolls (~75000 deaths) that might start appearing approximately 6-7 months after the withdrawal of current lockdown. Strikingly, we notice that a prolonged lockdown until January, 2021 might reduce 20 % COVID-19 infected cases on September, 2021. In addition, this policy will open a window of 11 months to rebuild the health infrastructure in Bangladesh.

Moreover, it will also bring some hope of getting the novel COVID-19 vaccine to defeat the . CC-BY-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

The copyright holder for this preprint this version posted October 23, 2020. ; https://doi.org/10.1101/2020.10.21.20216812 doi: medRxiv preprint coronavirus outbreak. As Bangladesh encounters a three-way tug of war, a battle between the coronavirus pandemic, reviving the national economy and keeping society on an even keel, the policymakers need to come up with more appropriate lockdown exit framework in order to keep a sustainable socioeconomic structure of Bangladesh. In summary, we hope that our study will be useable for the policy speculation and regulating the future outbreaks in Bangladesh.

Statement on the second meeting of the International Health Regulations (2005) Emergency Committee regarding the outbreak of novel coronavirus (2019-nCoV)". World Health Organization (WHO)

Impact of lockdown on COVID-19 incidence and mortality in China: an interrupted time series study

Studying the progress of COVID-19 outbreak in India using SIRD model

Adjusted Dynamics of COVID-19 Pandemic due to Herd Immunity in Bangladesh

COVID-19: SEIRD Model for Qatar COVID-19 Outbreak

The basic reproduction number (R0) of measles: a systematic review

The authors would like to thank Dr. Fariha Jasmin Chowdhury for their critical comments as a general reader.