Learning to live with the virus is hardly an outrageous proposition. Most scientists believe Covid-19 is likely here to stay, and an increasing number of countries with high vaccination rates — such as Britain and Singapore — are opting for a strategy of coexistence, hoping it would eventually become a less dangerous endemic, like the flu.

But in China, Zhang's remarks drew a torrent of attacks online, with detractors accusing him of refuting the country's much touted zero-Covid strategy.

Some enraged nationalists called him a "traitor" who "blindly worshiped Western ideas." Others alleged he was colluding with foreign forces to sabotage China's Covid response. Still others sought to undermine his academic credentials, digging out his doctoral thesis published two decades ago and accusing him of plagiarism.

The attack on Zhang underlined the highly politicized nature of discussions around China's Covid-19 strategy.

Since China curbed its initial outbreak, the ruling Communist Party has held up the country's effective containment efforts as proof of the supposed superiority of its authoritarian political system. The success of its zero-Covid strategy is hailed as an ideological and moral victory over the faltering response of the US and other Western democracies, which had struggled to control surging cases and deaths.

"This is a mistake in Covid decision-making caused by the defects in the political systems of countries like the US and the UK, as well as an inevitable result of advocating individualistic values," wrote Gao, who was trained as an economist.

Without naming Zhang, the former minister said he was surprised to see some Chinese experts advocating for the coexistence approach.

Gao's article has further fueled nationalist fury against Zhang, while appearing to signal the government's continued commitment to its zero-Covid approach.

This commitment appeared to be reinforced on August 11, when police detained a teacher in the eastern province of Jiangxi for 15 days for commenting on a news article saying the country can "coexist with the coronavirus," according to a local government notice.

But still, many experts, scholars and supporters have rallied to Zhang's defense.

Some Weibo users said the attacks on Zhang are reminiscent of the Cultural Revolution, during which scientists — along with intellectuals and artists — were subject to public humiliation and savage attacks by the Red Guards for their perceived political unreliability.

This isn't the first time Zhang has drawn the ire of Chinese nationalists, who are increasingly dominating China's social media by attacking and silencing more liberal and moderate voices. Last year, he was accused of pandering to Western lifestyles when suggesting kids should have eggs and milk for breakfast for protein instead of traditional Chinese rice porridge.

Jin Dongyan, a virologist at the University of Hong Kong, said the rapidly shrinking space for public discussion on epidemic control strategy is concerning.

"Experts involved in decision making should be encouraged to communicate with the public, and different opinions should all have channels to speak up," he said. "From a public health perspective, it is unhealthy and outright dangerous to only allow one kind of voice."

He also tried to walk back on his earlier call for China to learn to coexist with the virus.

"The Covid-19 strategy our country has adopted is one that suits us the best at present," he wrote. "You have to try the shoes on yourself to know whether they fit properly."