Imperial College: Sustained Bangladesh lockdown could reduce levels of death by up to 92%

Analysis by the United Kingdom’s Imperial College Covid-19 Response Team concludes that a sustained lockdown similar to the one started in Bangladesh at the end of March could reduce the total number of deaths from the virus in the country by over 90%, potentially saving as many as 585,000 lives. However, to get this benefit, the lockdown would have to continue until a vaccine or effective treatment becomes available, the research report states, which could be many months away. Even with a sustained lockdown in place, the Imperial College team estimates that over 52,000 people could die from Covid-19 in Bangladesh.

The academic analysis, which was first published on March 26th but has not been reported on in relation to Bangladesh until now, also shows that less restrictive government policies to deal with Covid-19, involving either social distancing within the population or enhanced shielding of those over 70 years of age would both be far less effective than a lockdown. It estimates that the adoption of these policies would result in reductions in the number of deaths between 30% to 38%.

However, the report makes it clear that the actual number of deaths in Bangladesh from the virus will depend upon the effectiveness of the lockdown, “It is important to note that these [figures] are not predictions of what is likely to happen; this will be determined by the action that government and countries take in the coming weeks and the behaviour changes that occur as a result of those actions.”

The number of deaths in Bangladesh could also be affected by other factors which are not taken into account in the modelling, including the “underlying co-morbidities” within the population such as “hypertension, diabetes, and coronary heart disease” as well as the availability of the “standard of medical care.” The report states: “Differences in underlying conditions and health care capacity will likely result in different patterns in low income settings,” potentially causing higher levels of “overall mortality.”

The Imperial College Covid-19 Response Team which undertook the analysis comprises five different organisations: the WHO collaborating Centre for Infectious Disease Modelling, MRC Centre for Global Infectious Disease Analysis, Abdul Latif Jameel Institute for Disease and Emergency Analytics, and Imperial College London. The published paper credits 47 different academics including Professor Neil Ferguson who led the Imperial College team that published the original research earlier in March which spurred the British and US governments into announcing robust measures aimed at tackling the spread of Covid-19 in their respective countries.

The analysis contained in the report, which is the first attempt to analyse how many lives could be saved through different mitigation and suppression policies in Bangladesh, is likely to assist the country’s politicians and public health policy officials in determining how long the current lockdown should remain in place.

In recent weeks, some public health advocates and non-governmental organisations, including the country’s largest Brac, have questioned whether the lockdown’s impact on the country’s day-labourers and the poor, who will lose the ability to earn money for food, was too high a price to pay. The Imperial College report notes specifically that it did not “consider the wider social and economic costs of suppression which will be high and may be disproportionately so in lower income settings.”

The paper analyses the impact of different strategies on 202 different countries, taking into account, available or estimated (when not available) country specific information on population size and age distribution, average household size and ages of people within them, and patterns of contact and mixing between different age groups. The health impacts of the virus are based on hospitalisation rate and infection fatality ratios obtained from Imperial College’s previous analysis of data from China.

On the basis of an estimated Bangladesh population of 164.7 million, and assuming that each person with Covid-19 infected an average of 3 people (i.e. R₀ = 3), the researchers conclude that without mitigation efforts by the government, the epidemic would result in 153.2 million infected people, 3.9 million hospitalisations, 844,703 critical cases and 637,191 total deaths.

The figure of 637,191 deaths is 0.39% of Bangladesh’s total population, which is significantly lower than the percentage estimated to die in richer countries, which have a higher proportion of people aged over 65. In the United States for example, the analysis estimated that the percentage of the population that could die, assuming no mitigation efforts, was 0.8% of the population, over double the percentage in Bangladesh.

The Imperial College analysis shows that a lockdown in Bangladesh, if sustained, could however significantly reduce the number of deaths. On the basis that a lockdown reduces overall social contacts between people by an average of 75%, the number of critical cases would decline to 69,062, and the numbers of deaths to 52,141, reducing the percentage of the total population that would die from the virus from 0.39 % to 0.032 %. This is a decline of 92% in both the number of critical cases and deaths. It would also reduce the hospital bed demand at the peak of the epidemic from 313,157 to 17,358 — a reduction of 95 %.

The numbers projected by the Imperial Covid-19 Research Team assumes that the Bangladesh government started its lockdown when there were no more than two deaths per million of the population over a period of a week. In Bangladesh, the lockdown started on March 26th, at which point there were officially only five deaths from the virus, a much lower death rate. The research does not clarify whether an apparently early lockdown in Bangladesh may mean that there will be fewer deaths.

Whilst the impact of a lockdown in Bangladesh is significant, the research shows that its impact in richer countries is even greater.

The research also looked at the effect of other mitigation strategies in Bangladesh, less stringent than lockdown, one involving limiting social contacts by 40% within the general population and another involving shielding those aged over 70 and above, by reducing their social contacts by 60%.

It found that both these strategies resulted in far less reductions in the numbers of deaths. Assuming a policy of general social distancing, the number of deaths in Bangladesh would decline by only 30% to 445,820 deaths and by shielding of those over 70 years old would result in a decline of only 38% to 395,419.

As of April 23rd, there have been a total of 4186 confirmed cases, and 127 deaths from Covid-19 in Bangladesh.●

David Bergman (@TheDavidBergman) — a journalist based in Britain — is Editor, English of Netra News.

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