Official reports of the number of deaths caused by Covid-19 are likely a “significant undercount,” according to the World Health Organization, which estimated Friday that the pandemic’s total global death toll is between six and eight million people so far.

As of Friday, the coronavirus had officially claimed the lives of more than 3.4 million individuals worldwide, the WHO said. When unreported Covid-19 deaths as well as deaths due to Covid-19’s effects on mobility and hospital capacity are accounted for, however, the United Nations agency argued that the true toll could be two to three times higher.

In its annual World Health Statistics report (pdf), the WHO estimated that in 2020, at least three million deaths could be attributed, both directly and indirectly, to Covid-19. That’s 1.2 million more than last year’s official count of 1.8 million Covid-19 deaths.

Focusing on excess mortality—which includes correctly certified Covid-19 deaths as well as unreported and incorrectly attributed ones, plus deaths due to the negative impacts of the virus on daily life and healthcare systems—”provides a more accurate picture of the full impact of the pandemic,” the health agency wrote.

“Total deaths are at least two to three times higher than officially reported,” Samira Asma, WHO assistant director-general in charge of data, told reporters, according to Al Jazeera.

Now, with Covid-19 ravaging Latin America and Asia as new coronavirus variants spread, Asma estimated that “about six to eight million deaths” could be attributed to the pandemic.

Asma added that the WHO is collaborating with countries “to understand the true human toll of the pandemic so we can be better prepared for the next emergency.”

Some of the biggest barriers to accurately calculating the pandemic’s death toll, Reuters reported, include “the lack of reliable systems to log deaths in many countries,” as well as the fact that “in many cases people had died from Covid-19 before they had been tested for the virus.”

Still, the tendency to overlook indirect deaths means that “even in regions with relatively reliable reporting systems, undercounts were likely,” the news outlet noted. Reuters continued:

The WHO estimated 1.1 to 1.2 million excess deaths in the European region during 2020, double the 600,000 reported Covid-19 deaths.

In the Americas, the number of excess deaths was 1.3 to 1.5 million during 2020, 60% higher then the reported 900,000 Covid-19 death toll in that region.

The WHO’s raised estimates of the pandemic’s total global death toll come less than three weeks after the University of Washington’s Institute for Health Metrics and Evaluation said that “our analysis estimates that by May 3, 2021, the total number of Covid-19 deaths was 6.93 million, a figure that is more than two times higher than the reported number of deaths of 3.24 million.”

As the WHO noted Friday in its new report, “Pre-pandemic inequalities have driven the unequal global distribution of vaccines and run the risk of perpetuating the pandemic, which in turn has amplified existing inequality.”

“Achieving equal global vaccination is imperative, or the risk of a more virulent or transmissible variant remains high,” the agency added. “No one is safe until everyone is safe.”