The new figures mean that almost three times as many died as a result of the pandemic as the official tally of deaths caused directly by the virus.
Countries notified the WHO of 5.4 million deaths from Covid-19 between January 1, 2020 and December 31 last year. However, by looking at global excess deaths, the WHO said they estimated the real range to be a minimum of 13.3 million and a maximum of 16.6 million people having died directly and indirectly from the pandemic.
This figure takes account of those who died of the disease as well as those who were "indirectly" affected, including people who could not gain access to health care for other conditions when systems were overwhelmed during huge waves of infection. It also accounts for deaths averted during the pandemic, for example, because of the lower risk of traffic accidents during lockdowns.
"Over this period, 5.4 million deaths were reported to the WHO. The excess deaths are 2.75 times more than the deaths reported," Dr William Msemburi, technical officer at the WHO's Department of Data and Analytics, said at a press conference.
Egypt, Turkey, India and the US were among the 10 countries responsible for 68 per cent of all excess deaths, Dr Msemburi said. The other countries were Brazil, Indonesia, Mexico, Peru, Russia and South Africa.
The WHO describes excess mortality as the number of coronavirus-related deaths that occurred either as an immediate result of catching the virus or the pandemic’s toll on global health systems.
They said that in the Eastern Mediterranean area which covers much of the Middle East, there were around 310,000 deaths reported over the two years and excess deaths were placed at between 800,000 and 1.3 million but "only a few countries in the ... region had empirical information readily available".
“These sobering data not only point to the impact of the pandemic but also to the need for all countries to invest in more resilient health systems that can sustain essential health services during crises, including stronger health information systems,” WHO director general Tedros Adhanom Ghebreyesus said in a statement on Thursday.
The medical infrastructure in countries such as Lebanon was on the brink of collapse at the peak of the pandemic as hospitals struggled to accommodate and keep up with the steep rates of infections and deaths.
“Deaths linked indirectly to Covid-19 are attributable to other health conditions for which people were unable to access prevention and treatment because health systems were overburdened by the pandemic,” Dr Tedros said.
Other nations, including Libya, which was already reeling from political and economic turmoil, at one point experienced infection rates of up to 480 per cent, with numbers expected to be higher because of the lack of testing kits and underreported symptoms.
“The estimated number of excess deaths can be influenced also by deaths averted during the pandemic due to lower risks of certain events, like motor-vehicle accidents or occupational injuries,” the WHO report said.
Countries such as Australia, China and Vietnam showed negative figures for mean excess deaths for 2020 and 2021, meaning that even accounting for the pandemic fewer people died during that period than a normal year.
"Negative excess deaths could be observed if deaths that would have happened in the absence of the pandemic were averted due to measures taken to deal with the pandemic," the WHO report said.
South-East Asia, Europe and the Americas account for 84 per cent of the excess deaths, the report said, without naming the countries.
Countries with a mainly middle-income population accounted for more deaths (81 per cent) than those with a lower-middle-income population (53 per cent) and upper-middle-income citizens (28 per cent).
The high-income and low-income nations had the lowest rates at 15 per cent and 4 per cent, respectively.
The global death toll was higher for men than for women (57 per cent male, 43 per cent female) and higher among older adults.
The figures show the pandemic’s effects and will help shape long-term policies, the WHO said.
“Death is of course an important health outcome, and measurement of excess mortality is an essential component to understanding the impact of the pandemic," said Dr Samira Asma, assistant director general for data, analytics and delivery at the WHO.
"Knowing how many people died in this pandemic will help us prepare for the next."
The Technical Advisory Group for Covid-19 Mortality Assessment is a joint WHO-UN venture and has the task of providing data absent in countries that still lack the “capacity for reliable mortality surveillance”, the report said.