Scientists are working to develop a vaccine capable of stopping the spread of a mysterious new coronavirus that has infected thousands of people, mostly in China.

Government scientists in China, the United States and Australia, as well as those working at Johnson & Johnson, Moderna Therapeutics and Inovio Pharmaceuticals are all working quickly to develop a vaccine.

The hunt began Jan. 10, when Chinese scientists posted the genetic makeup of the virus on a public database. The next morning, researchers at the National Institutes of Health’s Vaccine Research Center in Maryland went to work. Within hours, they had pinpointed the parts of the genetic code that could be used to make a vaccine.

Historically, vaccines have been one of the greatest public health tools to prevent disease. But even as technology, genomics and global coordination have all improved, allowing researchers to move at top speed, vaccine development remains an expensive and risky process.

More than 130 people have died from the mysterious new coronavirus, according to official Chinese statistics, but the real number is likely much higher. A dearth of test kits has hindered health officials ability to accurately diagnose and track the illness.

Here’s what we know about how the disease has spread:

◆ China said on Wednesday that 132 people had died from the virus, which is believed to have originated in the central city of Wuhan and is spreading across the country. The previous count, on Tuesday, was 106.

◆ The number of confirmed cases increased by nearly 25 percent to 5,974 on Wednesday, up from 4,515 on Tuesday, according to China’s National Health Commission.

◆ Thailand has reported 14 cases of infection; Hong Kong has eight; the United States, Taiwan, Australia and Macau have five each; Singapore, South Korea and Malaysia each have reported four; Japan has seven; France has four; Canada has three; Vietnam has two; and Nepal, Cambodia and Germany each have one.

◆ Cases recorded in Taiwan, German, Vietnam and Japan involved patients who had not been to China. There have been no reported deaths outside China.

How the coronavirus could be affecting the global economy.

As the death toll from the mysterious coronavirus in China keeps rising, economic analysts have counseled caution. They say it’s too soon to sound the alarm about the impact on the world economy.

And yet, some American companies with a big presence in China are being forced to adapt. Starbucks, for example, announced on Tuesday that it was temporarily closing half of its stores there.

“The magnitude of the impact will depend on the duration of store closures as we work with local authorities to manage the situation and protect our partners and customers,” Pat Grismer, its chief financial officer, said during an earnings call.

Starbucks isn’t alone. Also shuttering shops were McDonald’s and Yum China, the country’s largest restaurant company, which operates the KFC, Pizza Hut and Taco Bell brands in China and also controls its own brands.

Hotels and resorts with properties in the affected areas, which include Macau, a special administrative region and gambling mecca, also saw the value of their shares sink. They include Wynn Resorts, Las Vegas Sands and MGM Resorts International.

Marriott, Hyatt and Hilton, which have several properties in China, also saw their stock prices slide.

Other brands that are popular in China, like Estee Lauder, Nike and Tapestry, which sells Coach, Kate Spade and Stuart Weitzman, are likely to see a dent in earnings, bank analysts said.

China is the world’s second largest economy.

The United States is expanding its screenings.

United States health officials have announced expanded screening measures for passengers arriving from China at 20 ports of entry to the United States.

Expanded screening had previously been at only five airports; now, the Centers for Disease Control and Prevention said that all 20 of its quarantine stations in airports and land stations across the mainland United States are participating, as well as those in Alaska, Hawaii and Puerto Rico.

[A plane carrying Americans is leaving from Wuhan. If you know anyone on board, or anyone trying to leave Wuhan, we would like to hear from you for a coming article. Please contact Miriam Jordan at miriam.jordan@nytimes.com to share your story.]

Americans are now discouraged from traveling to any part of China, and other travel restrictions have not been ruled out, officials said. Only five people in the United States are known to have been infected so far.

Officials also announced on Tuesday that Chinese authorities will allow teams of international experts, coordinated by the World Health Organization, to help with research and containment.

In the United Kingdom, the British Foreign Office is warning against all travel to Hubei Province and against all but essential travel to the rest of mainland China. (The warning does not include Hong Kong and Macau).

And the European Union — at the request of France, which has many citizens in the Wuhan area — announced that it was sending two flights to China to evacuate at least 350 healthy citizens of the bloc.

Reporting was contributed by Chris Buckley, Russell Goldman, Elaine Yu, Raymond Zhong, Alexandra Stevenson, Paul Mozur, Knvul Sheikh, Katie Thomas, James Gorman, Motoko Rich, Ben Dooley, Eimi Yamamitsu and Patricia Cohen. Jin Wu, Zoe Mou, Albee Zhang, Amber Wang, Yiwei Wang and Claire Fu contributed research.