You may think Hong Kong people look irrational in these days of coronavirus: they queue for hours for masks, even if many doctors repeat that, in most situations, they are not all that necessary or even helpful. They stock up on hand wipes, bleach and disinfectant, leaving shelves empty. They buy up all the toilet paper and tissues they can find, just upon a rumor that circulates online and in telephone chat groups warning supplies from China might run short.

But this behavior isn’t proof of an illogical and superstitious population: Call it the consequences of trauma.

Hong Kong is on edge as it waits to see if the new coronavirus, which has killed more than 1,000 people in mainland China, will spread in the territory, where it has already killed one man and infected nearly 50. People don’t believe they can count on the government, either the one here in Hong Kong or the one in Beijing, to keep them safe and tell them the truth. That lack of trust between the city’s people and the local and central authorities runs deep, and worsened last year over more than six months of protests that rocked Hong Kong. The events of 17 years ago were responsible for cementing that distrust, when Hong Kong found itself alone for weeks as a mysterious new virus killed hundreds while central authorities in Beijing remained silent.

The eventual tally of victims of SARS in Hong Kong shows how high a price the city paid: Out of 774 deaths globally, 299 took place in Hong Kong, while 349 died in the mainland.

In an uncanny parallel with the ongoing outbreak in mainland China, SARS hit Hong Kong at a time of heightened political strife. At the end of 2002, Tung Chee-hwa, Hong Kong’s first chief executive after the handover of sovereignty from British to Chinese rule, was spearheading the introduction of the controversial Article 23 of the Basic Law, Hong Kong’s mini-Constitution. This stipulates that Hong Kong “shall enact laws on its own to prohibit any act of treason, secession, sedition, subversion against the Central People’s Government”—a provision that was revised to be more stringent after the widespread support shown by Hong Kong to the students who demonstrated in Tiananmen Square.

Throughout the second half of December 2002 people had been marching and holding rallies asking the government to withdraw the proposed Article 23 bill, and to have a much larger public consultation about it—or to wait for the implementation of full universal suffrage before imposing a law that could severely restrict local freedoms.

Then, as the new year set in, all activities, political and otherwise, came to a frightened halt. I was among the many journalists trying to comb through mailing lists and asking friends in China for their first-hand experiences, in the hope of making sense of what was happening. At the end of February a visitor from nearby Guangdong province, Liu Jianlun, came to Hong Kong to attend a wedding banquet and spent the night in a hotel. After one day, he went to hospital with shortness of breath, fever and heart palpitations. Ten days after having been admitted to the Intensive Care Unit, he died of acute pneumonia. He became known as “patient zero” for Hong Kong.

Thing is, nobody knew anything. Actually, that’s not quite correct, as somebody did: The authorities in Guangdong and Beijing knew, but they weren’t telling. We now know that the first human case was identified in Guangdong on Nov. 16, and that on Jan. 23 health authorities in Guangdong produced an expert investigation report that was circulated only with some other mainland authorities. They didn’t send it to Hong Kong, nor to the World Health Organization—which was notified only Feb. 10, 2003.

December, January and February were the months when all rumors were left to thrive, just like the virus. No social media existed at the time, but people were frantically texting to each other about a new type of acute influenza that was making people cough and wheeze. I remember going to Shenzhen in early March, and on the way back, as I was crossing the border at the Luo Wu checkpoint on foot, street vendors were trying to convince me to buy a surgical mask: “You should get one if you are going to Hong Kong. There is a strange disease there,” one said. I tried to argue that in that case she should be wearing one too as the disease was coming from Guangdong, and surely Shenzhen was not immune, but she just laughed me off, pushing the masks towards me. I didn’t buy any. There had been a text message redistributed about 125 million times in Guangdong, which read “There is a fatal flu in Guangzhou”—but either she hadn’t received it, or she wasn’t concerned.

Through March and April, Hong Kong became a terrified town. The virus spread incomprehensibly through a whole housing estate, affecting 321 people, and scaring medical workers overwhelmed by a virus too new to understand fast enough. Daily briefings on the spread of the disease did nothing to allay fears: only slowly did the medical community understood how contagious the disease was once a patient had to be put under a respirator, but before this, doctors had to witness their colleagues get sick and even die. Hundreds of medical workers fell ill, and at least eight died.

People didn’t know what to do. Some stayed home for weeks, venturing out only to get provisions. On Mar. 12, 2003, WHO issued a worldwide alert about Hong Kong and Vietnam, keeping China out of it. Restaurants were closing down, the economy had come to a halt. Tung had refused to close the airport, but hardly anyone was coming anyway. At the end of March, Sidney Cheung, a renowned surgeon and the former dean of medicine at the Chinese University of Hong Kong burst into tears in front of reporters, said we were battling “an unknown enemy” and called the situation “a Holocaust.”

Wedding parties took place with everyone in a surgical mask, skipping the banquet. Nobody dared press the buttons of the lifts, or open doors. People were going around with shower caps on their heads, goggles, even surgical gloves. Undecided on how to react as the central government said nothing, the local authorities hesitated, too: Only on Apr. 17 did Betty Tung, the wife of the chief executive, visit Amoy Gardens to hand out masks, but she arrived so wrapped up in protective plastic that people felt more insulted than supported.

China started to admit to a few isolated cases. Then, on Apr. 4, Jiang Yanyong, a military doctor, accused the authorities of a criminal cover up (paywall): He knew that in Beijing military hospital 309 hundreds of patients were being hidden from the WHO, and his public letter, smuggled to the international media, put an end to the cover up. President Hu Jintao admitted publicly the disease was still spreading on Apr. 17. Just two months before, on February 11, Zheng Dejiang, then Party Secretary of Guangdong, had called a press conference to say that there might have been a disease previously, but all was sorted out. No need to panic. And anyway, epidemics are a state secret.

As the weather became warmer, the virus subsided. The surgical masks felt sticky in the spring humidity, and most people had started to discard them. A short movie made by Hong Kong filmmaker Peter Chan, “Memories of Spring” summed up the transition from utter despair to a renewed will to fight. And fight Hong Kong did: so much so, that it put SARS behind it to take the streets again. Half a million people marched on July 1. They encircled the Legislative Council, and eventually stopped Article 23 from being implemented. But the betrayal from the central authorities, who kept the secret as hundreds died, could never be put entirely away.

Correction, Feb. 13: At least eight medical workers died in Hong Kong during the SARS epidemic up to June 2003. This article earlier said at least 70 medical staff died of SARS.