Nearly 15 million excess deaths occurred globally in 2020 and 2021

World Health Organization research suggests that during just the first two years of the pandemic, 14.83 million more deaths occurred worldwide than would otherwise have been expected

By Carissa Wong

Nearly 15 million excess deaths from any cause may have occurred during 2020 and 2021, nearly three times the 5.42 million covid-19 fatalities that were reported over the same two-year period.

William Msemburi at the World Health Organization in Geneva, Switzerland, and his colleagues estimated the number of deaths that would have occurred globally from January 2020 to December 2021 if the pandemic hadn’t taken place.

For some countries, the team used mortality data from 2015 to 2019 to calculate the number of expected deaths per year, which they compared with the number of reported deaths from any cause over two years of the pandemic.

In the countries that lacked the necessary mortality data, such as some in Africa and the Middle East, the researchers used a statistical model to predict their excess deaths. Based on countries where mortality statistics are available, the model linked excess fatalities with factors that can influence death rates, such as covid-19 restrictions and the prevalence of other conditions, such as diabetes.

Results suggest 14.83 million excess deaths occurred worldwide from the start of 2020 to the end of 2021, of which just under 5 million were in 2020 and more than 10 million were in 2021.

“We think the doubling in mortality in 2021 compared to 2020 is not only due to more infectious [covid-19] variants, but also because covid-19 was spreading into populations that had less access to vaccination,” says Msemburi.

Excess deaths may also include people who died from non-covid causes following delayed health screenings or because of a reluctance to seek medical attention amid the height of the pandemic.

The country with the most excess deaths relative to its expected number of fatalities was Peru, which saw twice as many deaths from 2020 to 2021 compared with pre-pandemic years. This was followed by Ecuador and Bolivia, which each had 1.5 times more deaths.

“This does not mean these countries responded worse to the pandemic, there are many factors that could be at play, including the timing of outbreaks in different countries, which covid-19 variants were dominant, as well as vaccination rates,” says Msemburi. Peru, for example, may have also improved its reporting of deaths amid the pandemic, creating the illusion of an increase in excess fatalities, he says.

“Comparing excess mortality in different countries can be of aid in evaluating the impact of different measures taken by governments around the world, which may in turn aid in fighting future pandemics,” says Giacomo De Nicola at the Ludwig Maximilian University of Munich, Germany.

Nevertheless, for many countries in the study, the expected deaths from 2020 to 2021 were predicted using a model that doesn’t account for the fact that populations may be ageing or becoming younger, says De Nicola. An ageing population would increase the expected mortality and reduce the estimated excess mortality, he says.

“We are making further improvements to the model that will improve the estimates,” says Msemburi. In addition, reported covid-19 cases and deaths are always below their true numbers, he says.

Journal reference: Nature, DOI: 10.1038/s41586-022-05522-2