Hong Kong declared a state of emergency on Saturday in response to growing concern over the spread of a coronavirus that first surfaced in the Chinese city of Wuhan, announcing it will close schools for three weeks and impose a limited transportation ban.

Chief Executive Carrie Lam held an urgent meeting with health officials Saturday morning to discuss the mysterious virus, which has — in limited numbers — begun to affect people across the globe.

According to data compiled by researchers at Johns Hopkins University, there are currently over 1,400 confirmed cases worldwide: While most have occurred in mainland China, 38 cases have also been confirmed in 13 locations abroad — including five cases in Hong Kong. According to Reuters, an additional 122 people are suspected of having the virus and are undergoing precautionary treatment.

The first case in Hong Kong was confirmed on Wednesday; four new cases surfaced by Friday night — all involving people who had visited Wuhan.

In response, Hong Kong is taking precautionary measures, according to the Hong Kong Free Press: schools and universities, which are already closed for the Lunar New Year, will not open until February 17. Transportation from Wuhan will be cancelled until further notice. And major public events, including annual Lunar New Year celebrations and a marathon next month, have been scrapped.

Lam also promised to deploy all the resources needed to prevent the disease, including increasing the supply of surgical masks for people to wear in public. The government will support medical staffers’ and overtime pay as well, she added.

The public health concern comes amid an ongoing period of political tension — antigovernment protests calling for democratic reforms (and Lam’s resignation) have stirred the city since last summer. Now, Lam is calling for a truce: “We must stand united so that we can prevent and control the disease. We hope we can safeguard public health and public safety,” she said.

Hong Kong isn’t the only place scrambling to protect its citizens from the virus. The United States, France, and Russia are all working to evacuate their citizens in Wuhan despite travel bans declared by the Chinese government, according to the Washington Post.

The US plans to fly its citizens and diplomats out via a charter flight on Sunday. France is negotiating a deal with China that would see its nationals transported to Changsha, a city 100 miles away from Wuhan, by bus. Russian officials are also working with the government to ensure the quick repatriation of its citizens, with Russian officials estimating up to 7,000 Russians are currently in China as tourists.

Officials at the Centers for Disease Control and Prevention (CDC) have said those outside of China have little to worry about at the moment, but have also stressed that governments are correct in erring on the side of caution given scientists are still learning about the virus and its transmission rate, as Vox’s Julia Belluz has reported:

Nancy Messonnier, director of the CDC’s National Center for Immunization and Respiratory Diseases, said Friday that although the outbreak is a “very serious public health threat, the immediate risk to the US public is low at this time.” Yet Tom Frieden, the former director of the CDC, told Vox he’s concerned by how infectious the virus is. “If the sustained human transmission and a high rate of severe illness are confirmed, then it clearly is an event of international concern.”

Despite assurances that any threat posed by the virus is largely concentrated in mainland China — and the precautions being taken by the government — some Hongkongers are concerned officials have reacted too slowly, noting rail passengers weren’t required to fill out health declaration forms until confirmed cases surfaced in Hong Kong.

The public still remembers the severe acute respiratory syndrome (SARS) coronavirus of 2003 that killed 299 Hongkongers — a death toll many blame on the government’s lack of proactiveness at the time. Now, Hong Kong’s streets are reportedly filled with people wearing masks, a reminder that Hong Kong is no stranger to a deadly disease.

Global health experts argue travel bans don’t work

As of now, the government of Hong Kong has no plans to completely limit travel to mainland China — only planes and trains to and from Wuhan will be suspended. All visitors from the mainland, however, will have to sign a health declaration form.

It’s a smart move because travel bans aren’t actually that effective. Global health officials have become slow to recommend them in recent years given travel bans didn’t stop the spread of AIDS/HIV in the 1980s, the H1N1 swine flu in 2009, or the SARS outbreak in 2003, as Vox’s Julia Belluz and Steven Hoffman noted in their report on China’s newly imposed travel ban:

At best, travel restrictions, and even airport screenings, delay the spread of disease but don’t impact the number of people who eventually get sick. Instead, they make it harder for international aid and experts to reach communities affected by disease. They are also expensive, resource-intensive, and potentially harmful to the economies of cities and countries involved. China’s quarantine “could inadvertently make people have less confidence in the government response,” [Tom Inglesby, director of the Center for Health Security of the Johns Hopkins Bloomberg School of Public Health,] added. “It could increase fear about the outbreak in the public. If this outbreak were happening in the US, I would advise strongly against any attempt to quarantine a city.”

The Beijing-imposed ban currently affects three cities — Wuhan, Huanggang, and Ezhou. Together, they have a population of about 20 million people. Chinese President Xi Jinping has defended his government’s response — which includes the construction of new hospitals specifically to deal with the virus — and has warned of an “accelerating” crisis. Currently, all 41 deaths due to the virus have occurred on the mainland.

The effectiveness of these measures remains to be seen, but as Belluz and Hoffman report, governments with limited options often take every opportunity they can to show a concerned public they are acting decisively to stem outbreaks. However, Belluz and Hoffman write, one of the best courses of action is actually to provide education on ways to reduce the spread of illness.

And that seems to be Hong Kong’s strategy. The Hong Kong Centre for Health Protection recently shared advice on preventing illnesses with symptoms that closely resemble the symptoms of the new coronavirus. Tips include wearing a surgical mask while in crowded places and maintaining drainage pipes properly to ensure environmental hygiene. The goal is to prevent a repeat of the deadly SARS outbreak of 2003 — and the deaths and panic that came with it.