An effort by the World Health Organization to calculate the global toll from the coronavirus pandemic found that many more people have died than was previously believed -- a total of about 15 million by the end of 2021, more than double the official count of 6 million reported by countries individually.
But the release of the estimate, the result of more than a year of research and analysis by experts around the world and the most comprehensive look at the lethality of the pandemic, has been delayed for months because of objections from India, which disputes the calculation of how many of its citizens died and has tried to keep it from becoming public.
More than one-third of the additional 9 million deaths are estimated to have occurred in India, where the government of Prime Minister Narendra Modi has stood by its own count of about 520,000 fatalities. The WHO estimates the country's toll as at least 4 million, according to people familiar with the numbers who were not authorized to disclose them. That would give India the highest tally in the world, they said.
The New York Times was unable to learn the estimates for other countries.
The WHO calculation combined national data on reported deaths with new information from localities and household surveys, and with statistical models that aim to account for deaths that were missed. Most of the difference in the new global estimate represents previously uncounted deaths, the bulk of which were directly from covid-19. The new number also includes indirect deaths, such as those of people unable to access care for other ailments because of the pandemic.
The delay in releasing the figures is significant because the global data is essential in understanding how the pandemic has played out and what steps could mitigate a similar crisis.
"It's important for global accounting and the moral obligation to those who have died, but also important very practically. If there are subsequent waves, then really understanding the death total is key to knowing if vaccination campaigns are working," said Dr. Prabhat Jha, director of the Center for Global Health Research in Toronto and a member of the expert working group supporting the WHO's excess-death calculation. "And it's important for accountability."
To try to take the true measure of the pandemic's effect, the WHO assembled a group of specialists including demographers, public health experts, statisticians and data scientists. The Technical Advisory Group, as it is known, has been collaborating across countries to try to piece together the most complete accounting of pandemic deaths.
The Times spoke with more than 10 people familiar with the data. The WHO had planned to make the numbers public in January, but the release has continually been pushed back.
Recently, a few members of the group warned the WHO that if the organization did not release the figures, then the experts would do so themselves, three people familiar with the matter said.
A WHO spokesperson, Amna Smailbegovic, told reporters: "We aim to publish in April."
Dr. Samira Asma, the WHO's assistant director-general for data, analytics and delivery for impact, who is helping to lead the calculation, said the release of the data has been "slightly delayed" but that it was "because we wanted to make sure everyone is consulted."
India insists that the WHO's methodology is flawed.
"India feels that the process was neither collaborative nor adequately representative," the government said in a statement to the U.N. Statistical Commission in February. It also argued that the process did not "hold scientific rigor and rational scrutiny as expected from an organization of the stature of the World Health Organization."
The Ministry of Health in New Delhi did not respond to requests for comment.
India is not alone in undercounting pandemic deaths, according to the new WHO numbers, which reflect undercounting in other populous countries such as Indonesia and Egypt.
Asma noted that many countries have struggled to accurately calculate the pandemic's effect. Even in the most advanced countries, she said, "I think when you look under the hood, it is challenging." At the start of the pandemic, there were significant disparities in how quickly U.S. states were reporting deaths, she said, and some were still collecting the data via fax.
India brought a large team to review the WHO data analysis, she said, adding that the agency was glad to have the team do it because it wanted the model to be as transparent as possible.
India's work on vaccination has won praise from experts globally, but its public health response to covid-19 has been criticized for the government's overconfidence. Modi boasted in January 2021 that India had "saved humanity from a big disaster." A couple of months later, his health minister declared that the country was "in the endgame of covid-19."
In February, India's junior health minister criticized a study published in the journal Science that estimated the country's covid-19 death toll to be six to seven times greater than the official number. In March, the government questioned the methodology of a study published in The Lancet that estimated India's deaths at 4 million.
"Personally, I have always felt that science has to be responded with science," said Bhramar Mukherjee, a professor of biostatistics at the University of Michigan School of Public Health who has been working with the WHO to review the data. "If you have an alternative estimate, which is through rigorous science, you should just produce it. You cannot just say, 'I am not going to accept it.' "
India has not submitted its total mortality data to the WHO for the past two years, but the organization's researchers have used numbers gathered from at least 12 states -- including Andhra Pradesh, Chhattisgarh and Karnataka -- which experts say show at least four to five times more deaths as a result of covid-19.
Jon Wakefield, a professor of statistics and biostatistics at the University of Washington who played a key role in building the model used for the estimates, said an initial presentation of the WHO data was ready in December.
"But then India was unhappy with the estimates. So then we've subsequently done all sorts of sensitivity analyses. The paper's actually a lot better because of this wait, because we've gone overboard in terms of model checks and doing as much as we possibly can given the data that's available," Wakefield said. "And we're ready to go."
The numbers represent what statisticians and researchers call "excess mortality" -- the difference between all deaths that occurred and those that would have been expected to occur under normal circumstances. The WHO's calculations include those deaths directly from covid-19, deaths of people because of conditions complicated by covid-19, and deaths of those who did not have covid-19 but needed treatment they could not get because of the pandemic. The calculations also take into account expected deaths that did not occur because of covid-19 restrictions, such as those from traffic accidents.
Calculating excess deaths globally is a complex task. Some countries have closely tracked mortality data and supplied it promptly to the WHO. Others have supplied only partial data, and the agency has had to use modeling to round out the picture. And then there is a large number of countries, including nearly all of those in sub-Saharan Africa, that do not collect death data and for which the statisticians have had to rely entirely on modeling.
Asma of the WHO noted that 9 out of 10 deaths in Africa, and 6 out of 10 globally, are not registered, and more than half the countries in the world do not collect accurate causes of death. That means that even the starting point for this kind of analysis is a "guesstimate," she said. "We have to be humble about it and say we don't know what we don't know."
Besides India, there are other large countries where the data is uncertain.
Russia's Ministry of Health had reported 300,000 covid-19 deaths by the end of 2021, and that was the number the government gave the WHO. But the Russian national statistics agency, which is fairly independent of the government, found excess mortality of more than 1 million people -- a figure that is reportedly close to the one in the WHO draft. Russia has objected to that number, but it has made no effort to stall the release of the data, members of the group said.
China, where the pandemic began, does not publicly release mortality data, and some experts have raised questions about underreporting of deaths, especially at the beginning of the outbreak. China has officially reported fewer than 5,000 deaths from the virus.
While China has kept caseloads at much lower levels than most countries, it has done so in part through some of the world's strictest lockdowns -- which have had their own effect on public health.
One of the few studies to examine China's excess mortality using internal data, conducted by a group of government researchers, showed that deaths from heart disease and diabetes spiked in Wuhan, China, during that city's two-month lockdown. The researchers said the increase was most likely due to inability or reluctance to seek help at hospitals. They concluded that the overall death rate in Wuhan was about 50% higher than expected in the first quarter of 2020.
India's effort to stall the report's release makes clear that pandemic data is a sensitive issue for Modi's government.
"It is an unusual step," said Anand Krishnan, a professor of community medicine at the All India Institute of Medical Sciences in New Delhi who has also been working with the WHO to review the data. "I don't remember a time when it has done so in the past."
Ariel Karlinsky, an Israeli economist who built and maintains the World Mortality Dataset and who has been working with the WHO on the figures, said they are challenging for governments when they show high excess deaths.
"I think it's very sensible for the people in power to fear these consequences," Karlinsky said.