The newly identified coronavirus that emerged last month from Wuhan, China, sickening more than 1,900 people worldwide and killing at least 56, has sparked growing anxiety and questions: How lethal is the virus? How can it be avoided? Is travel, especially to China, suddenly risky?

Here is what we know so far.

What is a coronavirus?

Coronaviruses are a large family of viruses that range from the common cold to much more serious diseases, according to the World Health Organization. They can infect both humans and animals. The newly emergent strain in China is related to two other coronaviruses that have caused major outbreaks in recent years: MERS, or Middle East respiratory syndrome, and SARS, or severe acute respiratory syndrome. The new virus hasn’t been named yet; it’s referred to as “a novel coronavirus.”

How do coronaviruses spread?

In rare cases, coronaviruses can spread from animals, such as camels and bats, to humans. (Household pets are not a threat.) The new virus is believed to have originated from a live animal market in Wuhan. But now it’s clear, health authorities say, that the virus is spreading from person to person — likely through coughing and sneezing or touching an infected surface and then the mouth, nose or eyes, or coming into contact with contaminated fecal matter.

What are the symptoms of infection from the novel coronavirus?

Symptoms range from fever, muscle aches, dry cough, runny nose and shortness of breath to much more severe problems such as pneumonia, kidney failure and acute respiratory syndrome. The elderly, young and people with weakened immune systems are at a higher risk of developing acute problems, such as bronchitis and pneumonia, according to the Centers for Disease Control and Prevention.

How deadly is this virus and how is it treated?

So far, the virus appears more serious than the common cold but less dangerous than SARS, public health experts have said. It does not appear to be anywhere near as deadly as Ebola, which is harder to transmit because it requires direct contact with an infected person’s blood or bodily fluids.

Antibiotics don’t work on viruses. There’s no medication for the new coronavirus, though the National Institutes of Health said human vaccine trials could begin within three months. Currently, health-care professionals are focusing on providing “supportive care,” including ensuring patients get plenty of liquids and oxygen.

Should people avoid traveling to China?

The situation is fluid but getting worse.

The CDC has urged travelers to avoid Wuhan. Several other Chinese cities also are essentially on lockdown. Even places that aren’t quarantined are experiencing disruptions and closures that could affect where travelers go and how they get around. For example, Beijing’s Forbidden City and Shanghai Disneyland have been shuttered, as have many theaters and temples.

Would-be travelers can stay abreast of developments by checking the CDC website and monitoring alerts issued by the State Department and U.S. embassies.

Beijing authorities are restricting the movements of their own people. Officials said all inter-province bus services to and from Beijing would be halted in an effort to contain the outbreak, according to local news reports. In addition, officials are suspending domestic and overseas Chinese group tours, state media reported.

Elsewhere in Asia, cases of infection appear isolated. Nevertheless, more vulnerable travelers, including those who have health issues or are older, should be cleared by a medical professional before departing.

If someone cancels a trip, will travel insurance refund the expenses?

Yes, if the insurance was purchased with the “cancel for any reason” benefit. This optional upgrade for the policy usually has several restrictions, but if the traveler meets the criteria, he or she can recover up to 75 percent of their trip costs. People with standard travel insurance who cancel because of fear of contracting the virus will have to absorb the losses, however. When traveling outside the United States, travelers should be sure they have travel medical insurance that will cover hospital costs if they fall ill while abroad or need to be taken back to the United States.

Are airlines, hotels and travel operators waiving change or cancellation fees?

Some airlines are. Cathay Pacific passengers who reserved a ticket on or before Jan. 21 can rebook, reroute their flight or receive a refund without penalty for travel through March 31. Air China is also waiving change and cancellation fees for tickets issued by Jan. 31 for travel by March 29. Other airlines that are loosening their rules include United, China Eastern, China Southern and Hainan. Some carriers, however, are taking a wait-and-see approach.

Some hotels also are making it easier to rejigger plans: Hilton, Accor, InterContinental Hotels and Hyatt are easing restrictions, and not just on Wuhan hotels. The waiver covers changes and cancellations at properties throughout China, for travel through early February. To qualify, the booking must have occurred directly through the hotel; otherwise, the third-party agent should be contacted.

Policies vary among tour operators and should be checked.

What's the situation at airports?

A large number of airports around the world have established enhanced screening procedures for passengers arriving from Wuhan, and a few countries, including India, are testing passengers arriving from any destination in China. South Korea’s Incheon International Airport is employing ear thermometers. In Japan, arriving passengers must fill out health forms. Australia is distributing pamphlets.

In the United States, the CDC and Customs and Border Protection are overseeing the process at five international airports in New York, Los Angeles, San Francisco, Atlanta and Chicago. Screening for symptoms and elevated temperatures may add a few minutes to the arrival process. Passengers who test positive for coronavirus will be quarantined for further testing by the CDC.

What's the best way for travelers to protect themselves before going to China?

The CDC recommends that everyone get a flu shot and other required vaccinations for their destinations. Any meat consumed should be fully cooked, and hands should be washed frequently and vigorously with soap and water for at least 20 seconds.

Jesus Gonzalez, a physician with MedStar Health in Washington, recommends that travelers wear medical masks in crowded areas, such as train and bus stations and airports.

What was China's experience with SARS and MERS?

The SARS epidemic began in November 2002, and the virus moved to more than two dozen countries over eight months, infecting more than 8,000 people and killing 774. Health authorities say that “Patient Zero” came in contact with an animal in China’s Guangdong province, which borders Hong Kong. The virus was finally contained in summer 2003. Health-care workers made up about 20 percent of the victims in areas hit hard by the disease, according to the World Health Organization. There’s still no cure for the disease, but the initial outbreak was contained by isolating suspected patients and screening passengers traveling from infected areas or those suspected of having symptoms.

MERS emerged in the Middle East in 2012. Scientists say the first infection moved from a camel to a human in Saudi Arabia. The disease has been associated with the death of 790 people since 2012, according to the CDC. ­Authorities contained the outbreak by isolating patients and warning against contact with camels and camel meat during the scare.