Official data from China offered a rare, but brief, glimpse of the true toll of Covid, indicating that nearly as many people may have died from the virus in a single province earlier this year as Beijing has said died in the mainland during the entire pandemic.
The data was deleted from a provincial government website just days after it was published on Thursday. But epidemiologists who reviewed a cached version of the information said it was the latest indication that the country’s official tally is a vast undercount.
The number of cremations in the eastern province of Zhejiang rose to 171,0000 in the first quarter of this year, the website said. That was 72,000 more cremations, a roughly 70 percent increase, than had been reported in the same period last year.
In February, China said the official death toll in the mainland since the start of the pandemic was 83,150 — a remarkably low number that independent researchers have said is not credible. Since then, the government has released only weekly or monthly death tolls that, when added up, raise the overall total to about 83,700.
Covid surged across China late last year, forcing the government to abandon its strict pandemic restrictions in December. The government’s abrupt policy reversal, however, left hospitals and pharmacies unprepared for the onslaught and likely accelerated the spread of infections and a wave of deaths across the country.
That surge of Covid infections across China lasted for about two months. The majority of the deaths occurred in January, but many people died in December as well. Epidemiologists estimate that 80 to 90 percent of the population was infected.
The Zhejiang data offered a window into cremation figures that have been closely guarded by the Chinese government. While the data does not include the cause of death, researchers regularly use excess death statistics to estimate the impact of major deadly events like disasters and pandemics. Everybody who dies in Zhejiang is cremated, officials say.
Many local and national authorities have withheld regularly published cremation data since that first major Covid wave started late last year. It is unclear why Zhejiang Province published data for the first quarter of this year, but three days after it surfaced, the report was removed.
Calls on Tuesday to multiple numbers at Zhejiang’s civil affairs bureau went unanswered. The Beijing-based media outlet Caixin reported on the figures Monday, but its article was also quickly taken down.
An analysis by The New York Times published in February estimated that China’s recent Covid wave may have killed between a million and 1.5 million people, based on research from four teams of epidemiologists.
The new data from Zhejiang — which is limited to a province of 65.8 million people — when extrapolated to the country’s population of 1.4 billion people, is roughly consistent with that range, experts from two of those teams said.
Ben Cowling, an epidemiologist at the University of Hong Kong, said that the data can be used for a crude estimate of China’s nationwide death toll. “I’m not sure the impact would have been exactly the same in every province, but I think it would be useful for a rough extrapolation,” he said. “It’s consistent with the estimates of around 1.5 million.”
Another team of researchers — Lauren Ancel Meyers, a professor of biology and statistics at the University of Texas at Austin and Zhanwei Du, an epidemiologist at the University of Hong Kong — reached a rough estimate of 1.54 million deaths from December through March in mainland China, based on the cremation count.
Last year, using an entirely different method based on tests of infections, vaccine effectiveness and other factors in China, the same research team estimated a most likely value of 1.55 million deaths for a slightly shorter period within a plausible range of 1.2 million to 1.7 million. The similarity of those figures to the current estimate probably indicates that Covid spread through all provinces in China in a similar way after the zero Covid policy ended, Ms. Meyers said.
“The fact that you end up with these very similar numbers suggests that things were equally devastating around the country,” Ms. Meyers said.
Yong Cai, a demographer at the University of North Carolina at Chapel Hill who studies mortality in China, arrived at an estimate of 1.5 million deaths for the first quarter of the year, based on the cremation data, and said that to gauge total mortality during the surge, deaths in December of last year, when cases started to spike, needed to be factored in.
He said he was surprised by Zhejiang’s cremation number. “It’s higher than I expected.”
Zhejiang is one of China’s wealthiest provinces, with good health care and an elderly vaccination rate above the national average. Its age distribution population is roughly representative of China on the whole, with 19 percent of the population over 60. In December, as Covid spread widely, Zhejiang’s health authorities announced that the province was recording one million infections a day.
All four epidemiologists and demographers cautioned that there are caveats and uncertainties in extrapolating the cremation data. But without more reliable data from China, academics say they have to rely on imperfect information to estimate the impact of the virus.
“We don’t have anything better,” Mr. Cai said.
Other recent clues hint at the impact elsewhere in the country. Data released earlier this year showed a substantial decline in Shanghai’s life expectancy, from 84.1 in 2021 to 83.2 in 2022, for the first time at this scale since 1983. The drop is likely attributable to the December Covid surge combined with a stringent lockdown in the spring of that year, which prevented some residents from accessing medical care, Mr. Cai said.
“I sincerely hope that the Chinese government can publish all the data available, make it transparent so people can understand what’s going on,” he said. “They have the data. It’s sitting somewhere.”
Joy Dong contributed reporting.
