In late December 2019, when nobody knew yet that a deadly coronavirus was brewing in the city of Wuhan, China, Dr. Li Wenliang, 34, an ophthalmologist at the Wuhan Central Hospital, became worried. The hospital was receiving an unusually large number of patients with severe cases of pneumonia that were traced to the nearby food market. On Dec. 30, suspecting the outbreak of a disease similar to SARS, which had killed hundreds in 2003, Li sent a warning to fellow doctors through the WeChat social media site. The next day, his message was widely circulating online.

As the number of severely ill patients kept growing, the hospital mobilized all doctors in the fight against the emerging epidemic. Li was spending long hours attending to the sick, terrified by the prospect of transmitting the disease to his pregnant wife and their 5-year-old son. On Jan. 3, in the middle of the night, he received an invitation to the local police precinct where he was asked to sign a warning against his behavior that “seriously disrupt[ed] social order” by “making untrue statements on the internet.” The document said, “If you are stubborn, do not reflect and repent, and continue to carry out illegal activities, you will be punished by the law.” Several other hospital staff members received similar warnings.

With no emergency declaration, the hospital had scarce supply of the proper protective equipment. Li had to use the same face mask for several days. On Jan. 10, he began coughing and developed a fever. After a CAT scan showed a lung infection, he was hospitalized. He died in the intensive care unit of Wuhan Central Hospital on Feb. 7 despite the desperate attempts of his colleagues to save his life. In his final days, Li told his followers on social media the full story of his attempts to warn the public and the government's efforts to silence him.

The news of Li’s death and the spread of the disease that led to city-wide quarantines and other war-like measures after the government failed to curtail the epidemic have triggered a hurricane of posts on Chinese social media expressing solidarity with the young doctor and disgust for the government. They were promptly removed by censors, but the sense of public anger they left brought back memories of Tiananmen Square and of the SARS epidemic, when another hero doctor revealed the outbreak of a deadly virus to the Western media.

Jiang Yanyong was a chief surgeon of the 301 Hospital in Beijing. In April 2003, after unsuccessful attempts to warn the government about the SARS epidemic, he gave a phone interview to the Wall Street Journal that resulted in the resignation of the Chinese Minister of Public Health. The worldwide response to SARS that followed prevented it from reaching the level of a pandemic. Jiang had been demoted and spent years under house arrest after he shared with the world his memories of treating victims of the Tiananmen Square massacre.

With China’s rulers refusing to learn the lessons of the past, the danger of a deadly pandemic that could kill millions keeps growing. Overcrowded living conditions of 300 million rural migrants that form half of the population in Wuhan, 40% of the population in Shanghai, and over 20% in Beijing, combined with unregulated food markets that facilitate the spread of viruses from animals to humans, have made Chinese megacities the major incubators of new strains of viruses.

Similar to how Russia tried to hide the Chernobyl disaster until radiation had spread to Europe, China hides health emergencies until they begin to spread beyond the country’s borders. In the interconnected world, this obsession with controlling health information affects everybody. It must worry China’s leaders too. If they do not begin to promote a more open society, the next pandemic or some other disaster could take their regime down the same way Chernobyl brought down the Soviet Union.

Eugene M. Chudnovsky is a Distinguished Professor at the City University of New York and Co-Chair of the Committee of Concerned Scientists.