While the official number of deaths from COVID-19 has topped 3.4 million globally, experts say this is undoubtedly an underestimate.
But by how much? And how can we know the true death toll of the pandemic?
Scientists are working tirelessly to try to find an answer to that question, which if found would be crucial in evaluating the historic impact of COVID-19—not to mention lessons to learn for the next global killer.
The World Health Organization (WHO) said on Friday that an estimated 6-8 million people were likely to have died due to COVID-19.
In a study earlier this month, the Seattle-based Institute for Health Metrics and Evaluation (IHME) used a variety of modelling techniques to estimate that a total of 6.9 million people died from COVID-19 since March 2020, more than two times the official toll.
The IHME calculated that the United States had seen 912,000 COVID-19 deaths, as opposed to the official toll of around 578,000.
The figure for India—736,000 deaths—was nearly three times higher than the official COVID-19 death toll there, IHME found.
According to the study, Mexico had seen 621,000 COVID-19 deaths, Brazil 616,000, and Russia 600,000—a toll far higher than the official figure of 111,000 deaths.
“In some countries, large degrees of under reporting are due to low levels of testing for COVID-19, this would be the case in Mexico or India,” IHME director Chris Murray told AFP.
In others, there “may be some official policy to be very restrictive in the definition of a COVID death”, he said.
“Such huge corrections to the official numbers are critical to understand where the pandemic has had the biggest effect,” Murray added.
“For the future, it will be very important for us to understand which countries had the greatest death toll and whether or not policy responses by government mitigated the impacts of the pandemic.”
Several countries have been accused of deliberately under-reporting COVID-19 deaths, most recently India, where the pandemic is still raging.
R.P. Singh, national spokesperson for the ruling BJP party said it was possible local health services were missing some COVID-19 cases, but insisted “there is no undercount happening in India.”
While IHME’s results are striking, they have not been universally accepted by experts.
“The model relies on a series of assumptions that may be reasonable globally but do not always apply to individual countries,” Steven Woolf, Director Emeritus and Senior Advisor at the Center on Society and Health at Virginia Commonwealth University of medicine, told AFP.
In the US, Woolf said that the IHME’s figure of 900,000 excess deaths was “reasonable”, but he questioned if they were all directly due to COVID.
Research supervised by Woolf has previously shown that around 70 percent of all excess deaths in the US since 2020 could be attributed to COVID-19.
Separating out deaths from COVID-19 and deaths that occurred during the pandemic from other causes—say, pneumonia or heart failure—is tricky.
“You need to separate out the direct effects from COVID from the indirect effects,” said Stephane Helleringer, a demographer at NYU Abu Dhabi and an expert adviser to the WHO.
Indirect effects include deaths from other diseases or conditions that hospitals—filled to the brim with COVID-19 patients—were unable to treat.
The inverse also needs considering: how many deaths were avoiding from fewer road traffic accidents or better urban air quality during lockdowns?
“At the global level, it’s extremely complicated,” said Helleringer.
When it comes to developing nations, which often lack the infrastructure to accurately record cause of death, the knowledge gap widens.
Malawi, for example, only records 10-15 percent of the causes of deaths occurring in the country, Helleringer said.
In nations such as Malawi, “we are totally unable to calculate excess deaths in real time,” said Helleringer.
More or less everyone agrees that the world’s official COVID-19 death toll is an underestimate.
The question, according to Helleringer, is: “To what extent?”
One study published this week in the BMJ medical journal estimated that around 1 million excess deaths occurred in 2020 in 29 rich countries—31 percent higher than the official COVID-19 toll.
But as Nazrul Islam, one of the paper’s authors from the University of Oxford explained, “estimates from these countries may not be extrapolated to other regions of the world”.
Such research only goes to highlight the vast differences in how countries go about collecting excess mortality data.
“If the question is: will we ever be able to estimate the effects globally in all the countries? The answer is probably: No,” Islam told AFP.
“Because many countries and regions do not have accurate and complete data on deaths.”
Helleringer said that there was still debate within the scientific community as to the true death toll of the Spanish flu, which ended more than a century ago.
“This is going to keep demographers and epidemiologists occupied for several years,” he said.