This is how China’s ruling Communist Party wants people to remember how it handled the Covid-19 pandemic: It was a “miracle in human history.” Every measure the government imposed was rooted in science, supported by the masses — and, ultimately, “completely correct.”

The party is waging an ambitious propaganda campaign to rewrite the public’s memory of “zero Covid,” a signature policy of China’s leader, Xi Jinping, that helped contain the virus for almost three years — but went to such extreme lengths that it smothered the economy and set off widespread opposition. In a decree that was published after a recent meeting of top officials and championed by a barrage of state media editorials, a newly triumphant narrative has emerged, aimed at bolstering Mr. Xi’s authority and deterring dissent.

The party is pushing its message at a time of heightening tensions with the United States over China’s handling of the pandemic, including the secrecy it has shrouded over investigations into the virus’s origins. The U.S. Energy Department recently concluded with “low confidence” that the Covid-19 virus likely originated from an accidental lab leak in China, a hypothesis that Beijing has denied and called a smear campaign even as some right-wing American media outlets have embraced it as fact.

And, forced to defend its policies domestically, China’s official messaging acknowledges none of the extremes of “zero Covid,” when authorities placed hundreds of millions of people under some form of lockdown last year, in some cases beating residents for leaving their homes or separating their children from them. Also missing from the narrative is the chaos that ensued after the policy’s abrupt dismantling in early December, which left hospitals and crematories unprepared for the explosion in new infections and deaths.

Instead, as the viral wave subsides, the party has declared that its efforts led China to a “decisive victory” over the virus, with what it claims is the lowest Covid death rate of any country in the world. Officials have sought to frame the abandoning of “zero Covid” as a carefully orchestrated pivot that was “optimized” to prioritize the health of its citizens. The term “zero Covid” itself, once ubiquitous, has vanished from the party’s rhetoric.

“The party is betting on the fact that if they just emphasize the positive evidence, then somehow after several years, people will have forgotten about all of this,” said Willy Lam, an analyst of Chinese politics who is a senior fellow at Jamestown Foundation, a think tank. “But this time around, we have seen very widespread expressions of dissent.”

China has long used censorship and propaganda to shape consequential moments in history that challenged the Communist Party’s legitimacy, a recurring exercise in state-sponsored amnesia. In recent months, officials have been quietly arresting and detaining several people who had participated in the nationwide protests last November against “zero Covid,” the biggest challenge to the country’s authoritarian leadership since the pro-democracy protests in Tiananmen Square in 1989.

But the aftermath of the pandemic may be especially challenging for the party to bury, as feelings of whiplash, grief and frustration simmer just beneath the surface for many Chinese residents.

“When I see government propaganda now about the pandemic, I feel sick,” said Liu Zhiye, 31, who works in real estate in Guangzhou, a southern city. “I try my best not to read it.”

Analysts say the campaign is aimed at quashing any resentment over the fact that China paid an enormous price in economic loss and trauma to enforce “zero Covid” — yet still suffered devastating health consequences, particularly among older adults.

Epidemiologists have estimated China’s Covid wave killed around 1 to 1.5 million people. But China’s official death toll for the entire pandemic is about 83,000 people, which researchers — and even many Chinese commenters on social media — regard as a severe undercount. A lower death tally helps bolster the government’s assertion throughout the pandemic that its model of one-party political control is superior to democracy.

“The government wants to say to people that their sacrifice was worth it,” said Yanzhong Huang, a global health expert at the Council on Foreign Relations.

For most of the pandemic, the looming threat of the virus punctuated the official rhetoric at all levels of Chinese government. Mr. Xi mobilized the country by declaring a “people’s war” against the virus, and a top party committee warned that local officials who hid infections would be “forever nailed to history’s pillar of shame.” State media outlets referred to the lockdowns of Wuhan in 2020 and Shanghai last year as “safeguarding,” as if the authorities were protecting citizens from an invading force.

When the party’s abrupt U-turn of its “zero Covid” policy accelerated infections and deaths, government censors initially struggled to find a coherent narrative.

Then came the party’s declaration this month that its pandemic policies were “completely correct,” after a closed-door meeting of the country’s top decision-making body, the Politburo Standing Committee, led by Mr. Xi. The lengthy decree sounded like the official conclusion of a chapter in the country’s history, with no space for further debate.

Minxin Pei, a professor at Claremont McKenna College who studies Chinese politics, said the meeting signaled a dramatic change in the party’s narrative on the reversal of “zero Covid.”

“Before that, it was tentative. Now, it’s quite aggressive messaging. The words they’re using now are really astonishing,” Professor Pei said.

“I expect in the next few weeks, you will see a proper campaign accentuating this triumphant message,” he added.

In a sign of how much the party intends to control the discussion, a social media post by a state television network about the meeting censored thousands of comments underneath it, displaying only a few dozen that praised the government.

Attempts to resurface painful memories from the “zero Covid” era have been censored online. Slogans like “we want food, not Covid tests” — a rallying cry during last year’s protests — have also been scrubbed from the Chinese internet.

As the Covid wave seemed to recede in January, state media outlets did warn about the lingering effects of long Covid, but some struck a more lighthearted tone. They borrowed a phrase trending on social media that labeled anyone who had not yet tested positive as a “final round player,” essentially comparing escaping the virus to a video game.

That same month, during Lunar New Year, a televised variety show watched by hundreds of millions of Chinese people made almost no mention of the pandemic. One of the few references was in a performance of a sunny ballad called “It Will Be Better Soon.” The lyrics included the line: “No more using masks.”

The government’s messaging is in line with efforts to restore the public’s confidence, both in the party’s leadership and in the country’s future. As China sets out to revive a flagging economy, it will need Chinese consumers to spend money again on homes, cars and plane tickets.

Many Chinese are indeed keen to put the pandemic behind them and look toward the future, to find jobs, rebuild struggling businesses and reconnect with the world.

On a trip back home to Shanghai this month, Rose Luqiu, an assistant professor of journalism at the Hong Kong Baptist University, found the memory of Covid to be a polarizing topic among her family and friends. Some people told her the experience made them consider leaving China.

But many others would change the subject, she said, recognizing that complaining in an authoritarian state was an exercise in futility. “People just want to get rid of all those bad memories,” Ms. Luqiu said.

From the beginning of the pandemic, the government has sought to silence those who challenged the official narrative. Officials disciplined Li Wenliang, a doctor in Wuhan, after he issued a warning in December 2019 about a mysterious new virus that ended up infecting and killing him. They arrested Zhang Zhan, a citizen journalist who tried to document the Wuhan outbreak, and sentenced her to four years in prison.

Mr. Liu, in Guangzhou, said he was eager to stop masking and to travel again. But he said he did not want the memory of the last three years — from the draconian restrictions to the widespread protests — to be erased.

“As long as there are people who can remember the suffering and absurdities of the past three years,” he said, “then we can fight against society forgetting.”