The novel coronavirus, or COVID-19, is spreading in the United States and dozens of countries around the world -- sparking anxiety and questions about the respiratory disease.
ABC News spoke with health experts to provide the latest information on how to try to stay safe.
1. What are the symptoms?
Novel coronavirus can cause symptoms that range from mild to severe, including cough, fever and shortness of breath. Since the symptoms are similar to those of pneumonia, influenza and the common cold, only a diagnostic test can confirm whether an individual has coronavirus.
2. How is it transmitted?
The first cases of COVID-19 were believed to be linked to a live-animal market in China, but the virus has since been spreading from person to person.
Person-to-person transmission is most likely between people in close contact, about 6 feet. When a person infected with novel coronavirus sneezes or coughs, respiratory droplets could land on people nearby or could possibly be inhaled by those people.
While the virus can be transmitted by touching objects or surfaces contaminated with COVID-19, health experts don't currently believe that's primarily how it's transmitted.
3. I live in the United States. What should I do?
The Centers for Disease Control and Prevention (CDC) warned that Americans should prepare for significant disruption in citizens' daily lives as the result of community spread of the virus -- cases with origin that is unknown.
The CDC advises making a plan. Schools and businesses should have systems in place for remote or virtual schooling and working remotely if face-to-face interactions must be restricted.
Dr. William Schaffner, medical director for the nonprofit National Foundation for Infectious Diseases, suggested sitting down and outlining a plan for how your family might handle schools and businesses closing. Does an older relative take prescription medication? Now might be a good time to stockpile at least two weeks' worth.
Call schools and ask if there are plans for remote schooling -- as some schools have done. Figure out a childcare plan in the event schools close, and ask about remote working options. Asking more questions now hopefully means asking fewer later.
For now, the CDC recommends Americans uphold proper flu season hygiene. Wash your hands often, stay home from work if you're sick and cough or sneeze into your elbow rather than your hand.
4. Should I wear a face mask?
Not unless you are the one who is sick.
The CDC doesn’t currently recommend any healthy person wear a mask and doctors warn fiddling with putting on and taking off a mask could backfire by exposing your hands to your face.
"Surgical masks fit rather loosely around the face and are not constructed, nor thick enough, to prevent infection," Schaffner said.
While they could have a modest benefit, any protection they provide is likely more psychological than scientific. N-95 masks, which hospitals use, are expensive and aren't easy to wear, meaning they're not a practical option for everyday use. As health officials have noted, masks should be reserved for the health care workers, not the general public.
"The other thing a mask can do is give you a false sense of security, and that's not helpful," said Dr. Michael Merson, a visiting professor at NYU's School of Global Public Health and a professor at Duke University. Masks work better at preventing people who are coughing and sneezing from spreading respiratory droplets and infecting others, but "those people who are sick should probably be at home anyway."
5. Should I be tested for the virus?
It's not completely up to you.
The CDC recently rolled out new guidance, allowing anyone to be tested for COVID-19 without restrictions, as long as their doctor approves. Testing is on the rise in the U.S., but experts say it is not yet enough.
If you have traveled to an area with local transmission or have been in close contact with someone who has been exposed to the virus, and develop symptoms, such as cough or fever, your health care provider can work with the local health department to determine whether you should be tested for COVID-19.
If you have symptoms, but no travel history to an outbreak area, you could go to a clinic and have a rapid test done to rule out more common viruses, such as influenza, Merson advised.
If you have mild symptoms and are worried that you might have COVID-19, call your doctor or local health department instead of going to a clinic or doctor's office without an appointment, to ensure you aren't potentially exposing others to the virus. If you have severe breathing problems, seek medical attention or call 911 immediately, recommends Dr. Jennifer Ashton, ABC News’ chief medical correspondent.
You should let the person you speak with know that you have respiratory problems and need to be isolated and seen right away.
6. Should I cancel my upcoming trip to Europe or Asia?
You might want to think about it. Depending on your destination, the decision may be out of your hands.
First, check the U.S. State Department's website, which provides travel advisories that include up-to-date recommendations about which countries have reported cases of COVID-19 and how widespread disease transmissions have been. The situation is fluid and rapidly evolving, so you should check back often and use that information to inform your decision.
Travel between Europe and the United States, for example, is restricted for 30 days, starting March 13. And the State Department is currently recommending that Americans reconsider all international travel.
"Even countries, jurisdictions, or areas where cases have not been reported may restrict travel without notice," the advisory states.
If you are in a high-risk group, meaning you are an older person, or have an underlying medical condition, "you should now be thinking about social distancing," Schaffner advised.
"Part of that is thinking really hard about whether you need to get on an airplane," he said. "I think this is a good time to postpone those trips."
Even if you're young, healthy and adventurous, there are additional questions to consider beyond whether the country you plan to travel to has seen a significant influx of COVID-19 cases.
Think about the situation on ground. Has travel within the country been disrupted? How would you feel about the potential of being quarantined upon your return to the United States? If it's a work trip, would the situation on the ground make it difficult to be productive?
Even if your trip is to a low-risk area, traveling on a plane will mean being in an enclosed space with fellow travelers. The CDC now recommends that all travelers, especially those with underlying health conditions, avoid cruise ships.
The answer may be different for different people. "Evaluate whether this is an essential trip," Schaffner said.
7. Do quarantines work?
"The short answer is apparently, yes, and better than we thought," Schaffner said.
After China imposed strict quarantine and lockdown measures in hard-hit Hubei province, new cases of COVID-19 appeared to decline, Schaffner explained.
It's too soon to know the full effect of that quarantine, which is essentially an unprecedented public health experiment. And imposing strict quarantine measures on an entire community may not be replicable outside of China.
Italy has locked down its entire population of 60 million, a dramatic move to try to tamp down on a rising number of cases and deaths.
"Try doing that in New York," Schaffner added. "Ain't gonna happen."
8. Is the outbreak a pandemic?
The World Health organization defines a pandemic as "the worldwide spread of a new disease," and on March 11, the WHO's director general announced that COVID-19 met those criteria.
Dr. Tedros Adhanom Ghebreyesus, the WHO's director general, stressed that the designation doesn't mean that citizens should stop trying to contain the virus.
"Find, isolate, test and treat every case, and trace every contact," he said. "Ready your hospitals. Protect and train your health care workers."
For the United States, community transmission in several cities and a growing number of cases that aren't able to be traced to travel or contact with individuals diagnosed with COVID-19 makes it probable that there will be extensive spread here.
"A lot of us have been sitting back and watching this from a distant place," Schaffner noted, adding that the game has changed in recent days. He cautioned against "running around like a chicken with its head cut off," and recommended thinking ahead. A large increase in cases in your community could mean school closures or other changes to your routine.
"Be prudent and be prepared to participate as much as you can in social distancing when that becomes the order of the day," he said. If health authorities advise against mass gatherings, for example, don't make a fuss.
"It shouldn't panic you," Schaffner said. "But it should get your attention."
9. How concerned should I be -- how does COVID-19 compare to the flu?
Concerned enough to pay attention. Stay on top of CDC updates and guidance, as well as from state and local health departments. Take the time to sit down and plan for what you'll do if local transmission of the virus occurs in your city.
Even the experts aren't completely sure what's going to happen.
"It's hard," said Dr. Stanley Perlman, a professor of microbiology and immunology at the University of Iowa, who described receiving a text message from his son earlier in the day that asked whether he should stock up on canned goods.
"I would be inclined not to," Perlman said. "We know from other cases that it actually tends to make things worse, because people stock up and then we don't have anything."
COVID-19 appears to be more fatal than the flu, with some studies pegging COVID-19's fatality rate at around 3.4%, while the flu's fatality rate is less than 1%. Still experts anticipate that COVID-19's mortality rate will fall when more people with mild symptoms are diagnosed with the virus. Typically, the sickest people tend to seek health care treatment first. Compared to past coronaviruses, such as SARS and MERS, however, most COVID-19 cases are mild.
"For most people, it's going to mean no disease or a mild illness," Merson said. Unfortunately, that mildness could also explain why COVID-19 is spreading more rapidly than highly fatal diseases do. HIV, for example, "was very fatal, but hard to transmit," he added.
10. Can kids get coronavirus?
Yes, but kids rarely have severe symptoms.
Reports from China include children who have contracted COVID-19, but those children typically had very mild symptoms and the majority of cases were diagnosed in adults. Severe complications from coronavirus, like acute respiratory distress syndrome and septic shock, are rare among kids. Similar to adults, children with underlying health problems may be at increased risk risk for complications associated with COVID-19.
11. Are pregnant women at higher risk?
We don't know.
Because COVID-19 is a new virus, we don't know whether pregnant women are more susceptible than the general population. Based on data from previous coronaviruses, like SARS and MERS, some experts believe that pregnant women may be at higher risk for severe illness and death, but that data is limited and far from conclusive.
For now, neither the CDC nor the American College of Obstetricians and Gynecologists recommend any specific guidance for pregnant women beyond what they recommend to the general public.
12. Is there a vaccine or treatment for COVID-19?
No. There are trials underway in China and elsewhere, but because the virus is new, there's no approved treatment for COVID-19 and a vaccine is likely more than a year away.
This report was featured in the Feb. 28 episode of “Start Here,” ABC News’ daily news podcast.
"Start Here" offers a straightforward look at the day's top stories in 20 minutes. Listen for free every weekday on Apple Podcasts, Google Podcasts, Spotify, the ABC News app or wherever you get your podcasts.