Modelling by MRC Centre for Global Infectious Disease Analysis suggests loosening of Bangladesh lockdown could result in daily infections increasing 18-fold
A decision by the Bangladesh government to relax its lockdown interventions by half could result in over 18 times increase in the number of new daily Covid-19 infections, according to epidemiological modelling by Imperial College’s MRC Centre for Global Infectious Disease Analysis (MRC GIDA).
The government has already started to relax some of its interventions by opening up shopping malls, mosques and garment factories. The current lockdown in Bangladesh — termed a “general holiday” — is due to come to an end at the end of May.
The MRC centre’s calculations are based on mathematical modelling which back-calculates the number of people that have actually been infected by the virus. It does this on the basis of the government’s official number of reported deaths and assumes “that 100% of Covid-19 related deaths have been reported.”
The centre notes that its projections should be seen as a “minimum” as it does not take into account any under-reporting of the Covid-19 death toll, “The extent to which reported deaths capture the true mortality is unclear, and will vary from one country to another depending on their vital registration system and surveillance methods. We do not therefore attempt to make any adjustment at present for under-reporting and it is likely that our projections are a minimum compared to the true overall mortality.”
The centre calculates that by May 20th, there were likely to have been a total of 67,661 newly infected people in the country over the previous four week period — including both asymptomatic and mild cases that “would not necessarily be identified through surveillance”. This is over three times the 21,739 people which the Bangladesh government had reported to have tested positive for the virus over the same period.
On May 20th, according to the MRC centre estimates, there would likely have been around 3,612 people newly infected with the virus — nearly triple the 1251 people who had tested positive for the virus on that day.
The centre goes onto calculate that if over the next two weeks, the government “scales up” its interventions by 50% — either by increasing current strategies or implementing new interventions — then, by June 3rd the numbers of new daily infections would reduce by a over a half, to about 1,596. (In the MRC report, the May 20th and June 3rd dates corresponds, respectively, to the days of May 19th and June 2nd dates on which Bangladesh government provides its figures)
If, however, interventions were “relaxed”, the number of daily infections will increase from an estimated 3,612 to 65,843.
“If current interventions were relaxed by 50%, we estimate the daily number of infections will change from 3,612 […] at the current date to 65,843 […] by 2020-06-03,” reads the MRC centre report. This is over eighteen times increase in the daily number of new infections compared to the May 20th estimated figure. The MRC centre produces this projection report for over 100 countries on a daily basis, with the results changing as the numbers of new deaths are reported.
The MRC centre report notes that these scenarios are unlikely to show significant differences in the use of hospital services by June 3rd, “due to the approximate 10 day delay between infection and hospital admission. Consequently, the effectiveness of a change in policy is likely to be better captured by hospital admission data approximately 2 weeks after the policy change is implemented.”
However, the report also notes that even if the government does not introduce any changes in its interventions, the demand for hospital beds with high pressure oxygen will in any case increase from an estimated 457 on May 20th to 708 on June 3rd, with demand for ICU beds increasing from 139 to 212.
According to Bangladesh’s Directorate General of Health Services (DGHS), on May 20th there were 370 patients requiring oxygen support — 73 patients in the ICU and 9 on the ventilator. However, an official admits that this data is only partial as “many facilities did not give information.” There are at present a total of 332 ICU beds throughout the country.
The MRC centre projections assume that approximately 5% of all Covid-19 infections will require treatment with high-pressure oxygen and that approximately 30% of hospitalised cases will require treatment with mechanical ventilation (based on an analysis of ongoing epidemics in Europe).
The MRC centre report does not provide any information on the impact of a rise in infections – were it to take place through the relaxing of lockdown – on the future numbers of deaths. It however does indicate that the number of daily deaths by June 3rd will in any case increase by around 27. On May 20th the official reported number was 21.
In assessing the impact of Bangladesh government’s “interventions” — and what “scaling up” or “relaxing” the interventions might mean — the MRC centre states that it uses the data from the Oxford Coronavirus Government Response Tracker which assesses interventions in every country in the world. As of May 17th, this assesses Bangladesh’s interventions as amongst the highest at 91 out of 100. However, the MRC centre notes, “We currently make assumptions about the efficacy of these interventions and so the projections should be interpreted as scenarios rather than predictions.” The centre also states on its website, “We currently capture [interventions] in a relatively simplistic way and so this may not fully represent the different interventions that are in place.”
The MRC centre states, “It is important to note that our model only provides an estimate of the direct mortality due to Covid-19 disease and not any indirect mortality that could occur as a result of either limited healthcare capacity or the wider response taken.”
The centre also notes, “Our outputs are provided to help support decision makers to interpret their current epidemiological situation and to provide short-term projections of the likely trajectory of the Covid-19 epidemic. They are, however, only one input to be considered prior to deciding on the most appropriate actions to take in response to this epidemic. […] [It] is likely that any actions taken to mitigate the spread of SARS-CoV-2 virus could impact in other ways that could impact both the health and livelihoods of populations. All of these factors should be considered in tandem to decide the appropriate national response.”●
🔗MRC Centre for Global Infectious Disease Analysis: Situation Report for COVID-19: Bangladesh, 2020-05-20 (Please note this report is updated on a daily basis, so numbers will likely be different if you access this page on subsequent dates )