American Airlines extended its flight suspensions to mainland China and Hong Kong through late April, citing “reduction in demand,” the company announced Tuesday.

“We will continue to evaluate this schedule and make any adjustments as necessary,” American said in a statement.

Other U.S. carriers have similarly suspended flights to China as the coronavirus outbreak continues. Delta Airlines canceled flights to mainland China through late April, while United Airlines suspended flights to China through late March and Hong Kong through late February.

In Geneva, top health officials have finally named the novel coronavirus that has sickened tens of thousands of people around the world.

The coronavirus is now called COVID-19, Tedros Adhanom Ghebreyesus, director general at the World Health Organization announced during a Tuesday news conference.

“Co” stands for coronavirus, “Vi” is for virus and “D” is for disease, Tedros explained. Health officials purposely avoided naming COVID-19 after a geographical location, animal or group of people.

“Having a name matters, to prevent the use of other names that can be inaccurate or stigmatizing,” he said.

In the United States, Dr. Anne Schuchat, principal deputy director of the Centers for Disease Control and Prevention, said the Americans who were evacuated on the first charter flight out of Wuhan, China, were expected to be released home Tuesday after completing a 14-day quarantine.

Those individuals are currently being assessed to ensure that they remain symptom-free, Schuchat said at the National Press Club on Tuesday.

The CDC is also re-examining whether 14 days is an appropriate duration for future coronavirus quarantines, as scientists learn more about the virus and how infectious it may be before patients show symptoms.

“There’s lots of different thinking right now from the anecdotes of the different countries’ experiences,” she added.

Schuchat also addressed lingering questions about coronavirus’ mortality rate, thought to be about 2%.

“We absolutely assume that the reported cases are an underestimate,” she said of coronavirus cases in China.

Since sicker individuals tend to seek health care treatment first, coronavirus’ mortality rate may drop as additional cases are reported.

On the other hand, in terms seeing how the disease progresses in individuals who are sickened, Hubei province and Wuhan have several weeks’ lead on the rest of the world. We may not know for a few more weeks whether the patients who have been sickened outside of China will ultimately recover, or if their conditions will worsen.

Coronavirus infects residents on different floors of apartment building, raising fears of disease’s spread

Meanwhile, a hundred people have been quarantined in Hong Kong after being evacuated from an apartment building where two residents living on different floors were diagnosed with the novel coronavirus, authorities said.

During a press conference Tuesday, officials from Hong Kong’s Center for Health Protection said the two infected residents were separated by 10 floors and the decision to partially evacuate the public housing estate in the city’s Tsing Yi area was made after the discovery of an unsealed pipe in the bathroom of the lower apartment, raising fears about how the newly identified virus may have spread between the two units.

So far, at least five other residents of Cheung Hong Estate who showed symptoms of the novel coronavirus have all been tested negative for the illness, according to Center for Health Protection director Wong Ka-hing. If all tests return negative, Ka-hing said quarantined residents could be released by the weekend.

Faulty piping in an apartment block led to the infection of hundreds of people in the semi-autonomous Chinese city during the deadly SARS outbreak in 2003.

The global death toll from the new coronavirus outbreak — 1,017 — has already surpassed that of the SARS epidemic. All but one of the deaths have occurred in China. The only death from the outbreak outside of China was in the Philippines.

Since the first cases were detected back in December in the Chinese city of Wuhan, the epicenter of the outbreak, China’s National Health Commission said Tuesday that it has recorded a total of 42,638 confirmed coronavirus cases. There are at least 319 cases confirmed in 24 other countries, according to the World Health Organization, which has declared the outbreak a global health emergency.

The number of cases confirmed in the United States ticked up to 13 on Monday, with another American diagnosed with the novel coronavirus in California, according to a U.S. Centers for Disease Control and Prevention spokesperson. The patient had arrived from China on the first evacuation flight to Marine Corps Air Station Miramar in San Diego. The flight landed at the military base on Feb. 5 and the passengers were to be quarantined for 14 days.

Other confirmed cases have been reported in the states of Arizona, Illinois, Massachusetts, Washington and Wisconsin. The CDC has shipped newly approved coronavirus tests to labs across the country so states can begin their own diagnostic testing instead of shipping all samples to the agency’s headquarters in Atlanta.

Prior to Monday, the last confirmed coronavirus case United States had been Feb. 5 in Wisconsin.

Meanwhile, the Untied Kingdom’s health department has declared the virus “a serious and imminent threat” and put new quarantine restrictions in place in an attempt to delay or stop the spread of the disease. Effective immediately, any individual public health professionals consider to be at risk for spreading coronavirus will be subject to a 14-day quarantine. Those restrictions only apply in England.

“I will do everything in my power to keep people in this country safe,” British health secretary Matt Hancock said in a statement Monday, while announcing the new rules. “We are taking every possible step to control the outbreak of coronavirus.”

The move came after a WHO news conference on Monday in which top health officials called reports of human-to-human spread of coronavirus in France “concerning.” The transmissions, which occurred at a French ski resort, are worrying instances of “onward transmission from people with no travel to China,” said WHO Director General Tedros.

“The detection of a small number of cases could be the spark that becomes the bigger fire,” he added. “But for now, it’s only a spark.”

The WHO convened in Geneva on Tuesday for a global research and innovation forum to identify the gaps in scientists’ knowledge about coronavirus and to accelerate the development of interventions to stem the spread of the disease.

“The bottom line is solidarity, solidarity, solidarity,” Tedros said during his opening remarks. “Publications, patents and profits are not what matters now. What matters most is stopping the outbreak and saving lives,” he said.

At the same time, an advanced team from WHO has begun its work in China. The international team will work with Chinese experts on the ground to investigate the origins and severity of the new coronavirus.

In Japan, thousands of people remain quarantined on the Diamond Princess cruise ship docked in the port of Yokohama since arriving there on Feb. 3. Among the 2,666 guests and 1,045 crew on board, at least 135 people have tested positive for coronavirus, including 23 Americans, according to a spokesperson for Princess Cruises, which operates the ship.

All those infected with the disease have been brought ashore for treatment, while the other passengers remain confined to their rooms on board until the quarantine period ends, according to Japan’s Ministry of Health, Labor and Welfare.

Some experts questioned whether the cruise ship quarantine was doing more harm than good.

“The issue with quarantine remains the lack of ability in a closed environment like this to maintain infection prevention measures on a ship,” said Dr. Eric Cioe-Pena, director of global Health at Northwell Health in New Hyde Park, NY.

“It’s a lot of people in close quarters that require high amounts of resources, clean water, readily available food, sanitation,” he said.

“We are seeing numbers increase dramatically, which likely means that there is ongoing spread of the virus on these ships. That’s concerning, as its creating a second epicenter of the infection, in a Japanese port,” Cioe-Pena added.

U.S. citizens Mark and Jerri Jorgensen, who are among the passengers on board, said they feel “well taken care of.”

“We’re not stressing out too much,” Jerri Jorgensen told ABC News in a telephone interview Tuesday. “We’ve got our medication. We got fresh linens for our beds. We’re not being left in the dark.”

“It’s a serious thing, we get that,” she added. “We are grateful that we’re being so well taken care of.”

Princess Cruises announced Sunday that it is offering a full refund to all guests on board the Diamond Princess.

“They gave us a complete refund, airfare and a credit for another trip,” Jerri Jorgensen said. “And people are like, are you going to cruise again? And the answer is yes, we’ve booked one for May.”

ABC News’ Jessica Mendoza, Christine Theodorou, Karson Yiu, Mina Kaji and Anne Flaherty contributed to this report.