New Delhi
A recently published article in a reputed international journal has provided estimates of all cause excess mortality for a number of countries based on a mathematical modeling exercise. The study has concluded that although reported COVID-19 deaths between Jan 1, 2020, and Dec 31, 2021, totaled 5•94 million worldwide, but an estimated 18•2 million (95% uncertainty interval 17•1–19•6) people died worldwide because of the COVID-19 pandemic (as measured by excess mortality) over that period.
This is yet another estimate on excess mortality due to COVID-19 by another set of researchers. Mathematical modelling techniques are essentially process of creating a mathematical representation of a real-world scenario to make a prediction. Such predictions are founded on certain set of inputs either based on real world scenarios, or approximations of those (which may vary in accuracy according to the technique used) inputs that are not available. Often these studies involve, taking a relatively small actual sample and extrapolating the result to the entire population. While this may achieve near accurate results for a small homogenous country/region, such techniques have failed repeatedly to give reliable results for a large, diverse population.The study takes into account different methodologies for different countries and for India, for example, data sources used by this study appears to have been taken from newspaper reports and non-peer reviewed studies. This model uses data of all cause excess mortality (created by another non-peer reviewed model) as an input and this raises serious concerns about the accuracy of the results of this statistical exercise.
Strangely, the methodology adopts data from newspapers at varied intervals to extrapolate (without any scientific basis) for the total period under study. The pandemic had multiple surges during the period and varied trajectories across different states (sub state level also) at any point of time. Hence the methodology used by this study is less than robust. Chhattisgarh’s excess mortality has been calculated based on an article that assumes that 40 times more deaths have occurred in April and May 2021. For states where Civil Registration System was available, reported deaths during the pandemic has been compared with average reported deaths for the same period in the year 2018 and 2019 which doesn’t take into account multiple pandemic management efforts including lockdown, containment zones, testing and contact tracing, wider dissemination and implementation of clinical management protocols and world’s largest vaccination drive, which form the foundation of pandemic management in the country.
Detailed guidelines for reporting of deaths due to Covid-19 have been issued by Union Health Ministry to all States/UTs. Indian Council for Medical Research (ICMR) on 10th May 2020 issued ‘Guidance for appropriate recording of Covid-19 related deaths in India’. The reporting of deaths is regularly done in a transparent manner and is daily updated in public domain on the website of Union Ministry of Health.Even the backlog in Covid-19 mortality data being submitted by the States at different times is reconciled in the data of Government of India on a regular basis. Furthermore, there is a financial incentive in India to report Covid-19 deaths as they are entitled to monetary compensation. Hence, the likelihood of underreporting is less.
It is noted that authors have themselves admitted that ‘Direct measurement would be preferable to modelled excess mortality estimates not based on all-cause mortality data, which are usually more robust, from the locations themselves.’ Further they have mentioned that ‘as studies from a few selected countries including the Netherlands and Sweden have suggested, we suspect most of the excess mortality during the pandemic is from COVID-19. However, sufficient empirical evidence is absent in most countries. Given the high amount of heterogeneity in epidemiological profiles among countries, it is prudent not to make such strong assumptions before more research on this topic is done.’
The authors have also accepted that ‘strict lockdown and mediation interventions can lead to negative excess mortality during the pandemic’ & ‘As more information becomes available in the near future, further improvements to our estimates are warranted.’ And that ‘various drivers are responsible for the changes in all-cause and cause-specific mortality in a population. Therefore, in estimating excess mortality due to COVID-19, the roles of confounders of changes in mortality during the pandemic should be resolved.’
They have themselves admitted that ‘Finally, the development and deployment of SARS-COV-2 vaccines have considerably lowered mortality rates among people who contract the virus and among the general population. As a result, we expect trends in excess mortality due to COVID-19 to change over time as the coverage of vaccination increases among populations and as new variants emerge. There will be great value in continuing to estimate excess mortality over time as these and other factors shift.’
It is highlighted that quoting issues as sensitive as death, that too during an ongoing global public health crisis like pandemic COVID-19, should be dealt with facts and with required sensitivity. This type of speculative reporting has potential to create panic in the community, can misguide people and should be avoided.
