20 million years of life lost to COVID-19

The COVID-19 pandemic has claimed more than 20 million years of life across 81 countries, according to a new analysis of the disease’s mortality through all of 2020. That’s an average of 16 years of lost life per death.

In heavily affected areas like the U.S., Western Europe and Latin America, COVID-19 has cost 2–to-7 times the number of lost years of life as a typical year of seasonal influenza, depending on the country. This is despite herculean public health efforts to stem the transmission of the disease. In these countries, the pandemic has also surpassed traffic deaths in number of years of life cut short and is comparable to heart disease, the leading killer in most countries.

The years of lost life metric, or YLL, measures premature mortality by subtracting the age at death from the life expectancy in a given country.

“The YLL doesn’t detract from still caring about metrics like deaths and cases. But it’s a measure that can directly assess the loss of human potential based off of the differences in how much life could have been lived,” says Adeline Lo, a professor of political science at the University of Wisconsin–Madison and a co-author of the new study.

Although COVID-19 has disproportionately killed older people, younger populations have suffered a similar burden of lost years of life. In many poorer countries, those under age 55 account for the majority of lost years.

And men have lost 44% more years to COVID-19 than women have on average. More men have also died of the disease.

The researchers also found that the true number of years lost to COVID-19 may be up to three times higher on average than what official records would suggest, due to an undercounting of deaths attributable to the disease.

Lo worked with health economist Héctor Pifarré i Arolas at the Universitat Pompeu Fabra in Barcelona, Mikko Myrskylä from the Max Planck Institute for Demographic Research in Germany, and others to perform the analysis. The authors published their findings Feb. 18 in Scientific Reports.

The scientists analyzed databases covering 1.2 million deaths attributed to COVID-19 as well as figures on life expectancy by country. For 19 countries, they were also able to calculate excess deaths, which is a measure of the increase in deaths observed in 2020 compared to 2010. Because some deaths may not be correctly attributed to COVID-19, and thus excluded from official counts, excess deaths provide another estimate of the true mortality of the pandemic.

“One of the big misconceptions was that this was not as bad of a pandemic as some people would have us believe. We believe that we have dispelled this notion.”

Héctor Pifarré i Arolas

Data on premature deaths can be skewed by factors like underlying health conditions that leave some people more prone to dying of a disease. For this reason, the ratio between years lost due to COVID-19 and other causes, like flu or heart disease, can be a more accurate measure of premature deaths, because those other diseases are similarly exacerbated by preexisting health problems.

In Italy and the U.S., two of the hardest-hit countries, COVID-19 has cost at least 7.5 more lost lives than the typical year of seasonal influenza. Roughly 20 countries have lost at least double the years of life to COVID-19 than to an average flu season.

While heart disease remains the number one cause of premature deaths in most nations, Mexico and Peru have lost more years of life to COVID-19. The pandemic has claimed at least half as many years of life as heart disease in Colombia, Ecuador and Brazil.

“One of the big misconceptions was that this was not as bad of a pandemic as some people would have us believe. We believe that we have dispelled this notion. This is a major pandemic,” says Arolas, the lead author of the new report. “And we have had an extraordinary public health response to the pandemic. Had we not done anything, these numbers would be much worse.”

Several countries analyzed in the study have not faced a severe burden of premature deaths due to COVID-19. Countries like Japan, New Zealand and South Korea have had relatively low case counts and a low mortality rate. Others, such as Bolivia, Cameroon and El Salvador, have only shared data from early phases of the pandemic so far and may report more deaths over time. The new study includes data through Jan. 6, 2021, capturing the entire first calendar year of the pandemic.

Other measures of the true health cost of the pandemic, such as the disability burden facing survivors, are not yet available. More research on the long-term consequences of COVID-19 infection and recovery needs to be done.

“Now that we have this information, let’s use it to identify where we should be preparing for the future to help vulnerable groups,” says Lo. “Now is a perfect time to integrate this information into not only helping us close down this pandemic, but also preparing for any future ones.”