Around 9,000 people in China are probably dying each day from COVID-19, UK-based health data firm Airfinity said on Thursday, nearly doubling its estimate from a week ago, as infections ripped across the world’s most populous nation.

COVID infections started to sweep across China in November, picking up pace this month after Beijing dismantled its zero-COVID policies including regular PCR testing on its population and publication of data on asymptomatic cases.

Cumulative deaths in China since Dec. 1 likely reached 100,000 with infections totalling 18.6 million, Airfinity said in a statement. It says it uses modelling based on data from Chinese provinces before the recent changes to reporting cases were implemented.

Airfinity expects China’s COVID infections to reach their first peak on Jan. 13 with 3.7 million cases a day.

That is in contrast to the several thousands of cases reported by health authorities a day, after a nationwide network of PCR test sites was largely dismantled as authorities pivoted from preventing infections to treating them.

Airfinity expects deaths to peak on Jan. 23 around 25,000 a day, with cumulative deaths reaching 584,000 since December.

Since Dec. 7 when China made its abrupt policy U-turn, authorities have reported 10 COVID deaths.

Health officials recently said they define a COVID death to be an individual who dies from respiratory failure caused by COVID-19, excluding deaths from other diseases and conditions even if the deceased had tested positive for the virus.

As of Dec. 28, China’s official COVID death toll stood at 5,246 since the start of the pandemic in 2020.

Airfinity expects 1.7 million deaths across China by the end of April, according to its statement.

According to its website, in 2020 it built “the world’s first dedicated COVID-19 health analytics and intelligence platform”.

China’s chief epidemiologist Wu Zunyou said on Thursday that a team at the Chinese Center for Disease Control and Prevention plans to assess fatalities differently.

The team will measure the difference between the number of deaths in the current wave of infections and the number of deaths expected had the epidemic never happened, Wu told reporters at a briefing.

By calculating the so-called “excess mortality”, China would be able to work out what could have been potentially underestimated, Wu said.