SEVENTEEN YEARS AGO this month, Swedish scientists first noticed disturbingly high levels of radiation on their monitoring screens -- the first signs of the Chernobyl disaster. But although Western scientists quickly pinpointed the source of the radiation in the Soviet Union, the Soviet leadership was slow to respond. For 18 days Mikhail Gorbachev, who had just taken power, said nothing. When he finally spoke, he accused Western media of sensationalism but also seemed genuinely affected by the suffering and illness. Within months, Chernobyl had helped persuade him to launch glasnost, a policy of greater honesty in Soviet public debate.

Watching China react to SARS, the mysterious new respiratory disease, it is impossible not to be reminded of Chernobyl. The illness was apparently first identified in China's Guangdong province last November. Nevertheless, as recently as April 4, the People's Daily, the Chinese Communist Party newspaper, announced that "SARS is largely under control." On April 5, a headline read, "Tourism in China continues without a hitch." By April 15, however, after the Chinese president, Hu Jintao, traveled to Guangdong, the paper had changed its tone, citing his new concern for "the people's safety." Over the past two days Chinese leaders have admitted that there are 455 SARS cases in Beijing, not 37; canceled May Day celebrations; announced that the "Ministry of Health was not adequately prepared for a crisis"; and fired the mayor of Beijing and the health minister for their roles in the coverup.

China's initial silence almost certainly had devastating effects. Had the disease been publicly identified early on, had victims been isolated and their contacts quarantined, SARS might never have spread, either within China or elsewhere. China's inaction may have led to 3,500 hospitalizations around the world and dozens of deaths, not to mention widespread economic damage. Worse, it may have ensured that the disease becomes permanently established. And the continued difficulty of getting information about the early progress of the disease is hampering efforts to understand SARS and find a cure, Western epidemiologists say. But whether the Chinese want it or not, information will continue to emerge. Like radiation, viruses know no political boundaries.

It is far too early to say whether the SARS fiasco will lead to a new era of glasnost in China. Nevertheless, this crisis does reveal a great deal about the odd state of contemporary Chinese politics. Although access to information is theoretically controlled, ordinary Chinese seem to have learned about the disease from foreign sources; they were donning face masks long before their government told them to. Although the Chinese establishment is meant to speak with one voice, a handful of Chinese doctors publicly contradicted the government's official pronouncements. In other words, there are more cracks in China's totalitarian armor than the Chinese and even some Americans are prepared to admit. The damage caused by secrecy in the SARS case shows why it is right to continue pressing China in every way possible to become more open.