The spread of a new coronavirus called the Wuhan pneumonia is ferocious.

As of Monday, China confirmed 2,744 people have been infected so far, including 80 dead. On Sunday alone, 796 new cases were confirmed and 24 died in China. It was the first time that the daily death toll from the virus had exceeded 20.

The effect of the Lunar New Year, known as the Spring Festival in China when hundreds of millions of people visit their hometowns or travel abroad, has not been reflected fully in the numbers yet.

The virus has not only spread through China but also to Asia, the US and Europe. It is feared that it may cause greater damage than severe acute respiratory syndrome, which affected 8,098 people and killed 774 in 17 countries in 2003.

As the number of Wuhan pneumonia patients has increased exponentially, Beijing has extended the holidays and postponed the new school semester. But it has been criticized for failing to respond quickly at the initial stage of the outbreak.

Though it took an extraordinary step by shutting down travel out of Wuhan on Jan. 23, about 5 million residents reportedly had already left the city either for the Spring Festival or fearing an outbreak of the virus. Many of them may have been infected with the virus.

China says the virus, unlike SARS, is infectious during its incubation period and has warned that people infected with the virus could be contagious for as many as 14 days before showing symptoms. It is also believed to be able to mutate.

South Korea confirmed its fourth case of the virus Monday. The patient, a Korean male, arrived here from Wuhan on Jan. 20 without symptoms and passed airport quarantine checks. He visited hospitals with fever, but was not diagnosed as infected with the virus. A week after entering the country, he was found to have contracted the virus.

The third, a Korean in his 50s, was not detected in the airport quarantine process either, because he had no symptoms. He voluntarily reported his symptoms to the public health center as he coughed up phlegm. He is said to have come into contact with 74 people over five days.

The two cases show blind spots in the nation’s airport quarantine system. No matter how well the system is set up at airports or harbors, it is almost impossible to detect patients who are still in the incubation period.

Out of the 5 million residents who escaped Wuhan before the travel lockdown, 6,430 traveled here by air from Dec. 30 to Jan. 22, according to data analysis.

Considering the latency period, the number of cases is likely to rise sharply in about two weeks. Furthermore, many Chinese students are expected to return to Korea after Feb. 2 at the end of the delayed Spring Festival. The health authorities should focus on the prevention of secondary infections.

President Moon Jae-in on Monday ordered checks on every individual traveler from Wuhan and the surrounding area. He even urged the mobilization of troops if needed. Just a day earlier, he had called on the people not to be “excessively anxious.” He should have taken preventive steps earlier. The checks must be conducted without a hitch.

Out of growing anxiety, citizens have filed online petitions on the website of the presidential office, demanding a ban on the entry of all Chinese travelers at least during the Spring Festival period. One of the petitions won support from more than 480,000 people as of Monday afternoon.

Taiwan did not permit visitors from Wuhan to enter the country. The Philippines repatriated more than 400 Chinese travelers from Wuhan and banned direct flights from the Chinese city. Hong Kong and Macao have restricted the entry of people from China’s Hubei province. Malaysia on Monday imposed a temporary ban on Chinese nationals from Wuhan and Hubei province.

Considering the political and economic ties with Beijing, it may be hard to take such action immediately. Nevertheless, when it comes to people’s lives, the government must brace for all scenarios, including a temporary ban on the entry of Chinese tourists. If the virus gets out of control, drastic measures will be inevitable. If the government dawdles, it will likely miss the chance. When a virus is spreading fast, a bold and proactive response is the way to go.