BEIJING (AP) — When China suddenly scrapped onerous zero-COVID measures in December, the country wasn’t ready for a massive onslaught of cases, with hospitals turning away ambulances and crematoriums burning bodies around the clock.

Chinese state media claimed the decision to open up was based on “scientific analysis and shrewd calculation,” and “by no means impulsive.” But in reality, China’s ruling Communist Party ignored repeated efforts by top medical experts to kickstart exit plans until it was too late, The Associated Press found.

Instead, the reopening came suddenly at the onset of winter, when the virus spreads most easily. Many older people weren’t vaccinated, pharmacies lacked antivirals, and hospitals didn’t have adequate supplies or staff — leading to as many as hundreds of thousands of deaths that may have been avoided, according to academic modeling, more than 20 interviews with current and former China Center for Disease Control and Prevention employees, experts and government advisers, and internal reports and directives obtained by the AP.

“If they had a real plan to exit earlier, so many things could have been avoided,” said Zhang Zuo-Feng, an epidemiologist at the University of California, Los Angeles. “Many deaths could have been prevented.”

Experts estimate that many hundreds of thousands of people, perhaps millions, may have died in China’s wave of COVID-19 — far higher than the official toll of under 90,000, but still a much lower death rate than in Western countries. However, 200,000 to 300,000 deaths could have been prevented if the country was better vaccinated and stocked with antivirals, according to modeling by the University of Hong Kong. Some scientists estimate even more lives could have been saved.

“It wasn’t a sound public health decision at all,” said a China CDC official, declining to be named to speak candidly on a sensitive matter. “It’s absolutely bad timing … this was not a prepared opening.”

For two years, China stood out for its tough but successful controls against the virus, credited with saving millions of lives as other countries struggled with stop-and-start lockdowns. But with the emergence of the highly infectious omicron variant in late 2021, many of China’s top medical experts and officials worried zero-COVID was unsustainable.

In late 2021, China’s leaders began discussing how to lift restrictions. As early as March 2022, top medical experts submitted a detailed reopening strategy to the State Council, China’s cabinet. The existence of the document is being reported for the first time by the AP.

But discussions were silenced after an outbreak the same month in Shanghai, which prompted Chinese leader Xi Jinping to lock the city down. Chinese public health experts stopped speaking publicly about preparing for an exit, as they were wary of openly challenging a policy supported by Xi.

By the time the Shanghai outbreak was under control, China was months away from the 20th Party Congress, the country’s most important political meeting in a decade, making reopening politically difficult. So the country stuck to mass testing and quarantining millions of people.