The World Health Organization (WHO) declared the outbreak of the COVID-19 pandemic on 11 March 2020. Two years later, it put the cumulative number of cases at about 452 million, more than 5 percent of the world’s population, and the number of new infections was still averaging more than a million a day.
How many people have died? We can begin to model the problem by using the highest mortality estimates of the two previous major pandemics—138 deaths per 100,000 people in 1957–1958 and 111 per 100,000 in 1968–1969. A similarly virulent two-year event, adjusted for today’s population of 7.9 billion, would then be expected to kill 8.8–10 million people. On 11 March 2022, the WHO’s officially logged COVID death toll was about 6 million. Every epidemiologist knows that this must be a significant underestimate.
A better way to assess the death toll is to calculate excess mortality, that is, the difference between the total number of deaths during a crisis and the deaths that would be expected under normal conditions. Obviously, this approach will work only in those countries that collect near-impeccable mortality statistics. The WHO has assessed the health-information capacity of 133 countries, showing that the share of all deaths that are registered ranges from 100 percent in Japan and 98 percent in the European Union to 80 percent in China and only 10 percent in Africa. Given these realities, calculations of excess mortalities are revealing in France, inaccurate in China, and impossible in Nigeria.
And even in Japan, interpreting excess mortalities can be complicated. On one hand, COVID excess mortality includes not only the deaths directly attributable to the virus (due to inflammation of tissues or oxygen deprivation) but also the indirect effects caused when COVID aggravates preexisting conditions (heart disease, dementia) or induces the deterioration and disruption of normal health care (forgone diagnoses and treatments). But on the other hand, the spread of COVID appears to have largely preempted seasonal excess mortality caused by winter flu epidemics among the elderly, and lockdowns and economic slowdowns improved the quality of outdoor air.
The officially logged COVID death toll is about 6 million; every epidemiologist knows that this must be a significant underestimate.
By the end of 2020 the official worldwide COVID death toll was 1.91 million, but the WHO’s preliminary evaluation estimated at least 3 million deaths. According to Seattle’s Institute for Health Metrics and Evaluation (IHME), which counts only cases caused directly by the virus, not by the pandemic’s disruption of health care, excess global mortality reached 15.34 million (that is, between 12.6 and 18.9 million) by 11 March 2022. That’s the second anniversary of the beginning of the pandemic, according to the WHO’s reckoning.
A model run by The Economist relies on scores of national indicators correlating with data on excess death and thus it has produced a wide range of estimates. For the pandemic’s 2-year mark, the range is between 14 million (2 times the official tally of 6.86 million) and 23.7 million (3.5 times the official number), with the central value at 20 million (2.9 times the official total). And on 10 March 2022, The Lancet, one of the world’s leading medical journals, published its excess mortality estimate for 2020 and 2021: 18.2 (17.1 to 19.6) million, nearly 3.1 times the official two-year tally.
Even using a toll of around 15 million deaths is enough to put COVID-19 far ahead of the two major post-1945 pandemics on a per capita basis. And any number above 20 million would make it in absolute terms (but not in relation to population) an event on the same order of magnitude as the great 1918–1920 influenza pandemic. Will we ever know the real toll to within 10 percent, plus or minus?
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Vaclav Smil writes Numbers Don’t Lie, IEEE Spectrum's column devoted to the quantitative analysis of the material world. Smil does interdisciplinary research focused primarily on energy, technical innovation, environmental and population change, food and nutrition, and on historical aspects of these developments. He has published 40 books and nearly 500 papers on these topics. He is a distinguished professor emeritus at the University of Manitoba and a Fellow of the Royal Society of Canada (Science Academy). In 2010 he was named by Foreign Policy as one of the top 100 global thinkers, in 2013 he was appointed as a Member of the Order of Canada, and in 2015 he received an OPEC Award for research on energy. He has also worked as a consultant for many U.S., EU and international institutions, has been an invited speaker in more than 400 conferences and workshops and has lectured at many universities in North America, Europe, and Asia (particularly in Japan).