As a city that lost nearly 300 people to the SARS virus in 2003, Hong Kongers are taking few chances over the latest disease outbreak that began in central China and has since spread.
Usually clogged streets have been uncharacteristically quiet, with light traffic and crowds over the Lunar New Year holiday.
But the one place Hong Kongers are still willing to gather in sizeable numbers is outside their local pharmacies, hoping to snap up rapidly diminishing supplies of surgical facemasks.
In the middle-class district of Tseung Kwan O, hundreds of residents patiently queued for hours on Thursday to buy masks at a pharmacy that, like many outlets, was now limiting sales to one box per person.
"No matter how long this queue takes and how much it costs, I will at least buy enough for myself," a 26-year-old woman, who gave her surname as Tam, told AFP.
Like many in the queue, she was angry at local authorities.
"I'm not satisfied with what the government is doing to prevent the epidemic. It doesn't close the border to mainlanders, and there is a lack of the supplies for masks in the market," she added.
Semi-autonomous Hong Kong has resisted public pressure to close its border with the Chinese mainland although it has shuttered some crossings.
A 17-year-old student, who gave her first name Michelle, said she had queued for more than an hour to get a box of masks.
"I hope this will be enough for a month. If I don't have enough masks, I might need to stay at home and can't go to school," she said.
The South China Morning Post reported that some people camped out overnight after Watsons, one of the city's largest pharmacy chains, said a limited supply of facemasks would be sold on Thursday.
Angry customers argued with staff outside some stores when supplies ran out, the paper reported.
Supermarkets have also seen their shelves cleared in some districts.
"I bought a bag of rice and some canned food too," a 60-year-old retiree surnamed Sin told AFP. "I am trying to avoid gathering with friends and reduce the amount of time to dine in at restaurants."
Hong Kong's government said it was "striving to procure more surgical masks to cope with the epidemic", adding it had contacted 140 suppliers in 10 countries.
It added that the "supply of surgical masks in the market would still be tight in the near future".
The city's customs department said it had also launched an operation to weed out counterfeit masks that did not comply with international safety standards.