What are the symptoms? How bad will the outbreak become? The latest advice to keep you informed and safe.

The coronavirus is a newly discovered strain of a family of viruses that infect animals and sometimes humans. Below are some common questions (and answers) about the rapidly spreading outbreak, now officially called coronavirus disease 2019 (COVID-19) by the World Health Organization (WHO) and previously referred to as the “2019 novel coronavirus” or 2019-nCoV.

Where did this new coronavirus virus come from?

The virus itself, named SARS-CoV-2 originated in bats, according to the U.S. Centers for Disease Control and Prevention. In December 2019, the first cases in humans were detected, in the Chinese city of Wuhan. Early cases are believed to involve people who had been to a large animal and seafood market. Two previous human outbreaks of coronaviruses — severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) — also originated in bats.

How contagious is this coronavirus?

The virus is now known to spread from human to human. How easily is not yet determined. Any given virus can spread reluctantly or be highly contagious. Measles, for example, is far more contagious than early analyses of this coronavirus indicate, says Nancy Messonnier, MD, director of the CDC’s National Center for Immunization and Respiratory Diseases.

One reason the disease appears to be spreading rapidly may be due to delays in confirming early cases in some countries, in part given that only recently has the ability to test for the virus gone beyond a few specialized labs, including in China and at the CDC.

“As this case confirmation process becomes more speedy, the reporting of cases will appear to be faster — not necessarily because of the disease spreading faster, but because of the ability to identify and confirm cases becomes faster,” says Dr. Wilbur Chen, associate professor of medicine at the University of Maryland School of Medicine. “Nonetheless, we also believe that the 2019-nCoV is efficient in transmission, meaning that it is capable of spreading fast.”

However, the rapid transmission of the virus on the cruise ship Diamond Princess, to at least 690 people and with three deaths, is one indicator that it spreads fast when people are in close quarters.

How deadly is it?

That can’t be determined conclusively yet, because the outbreak is still in its early weeks, and a full analysis isn’t possible. But the fatality rate has been “between 2% and 4% in Wuhan, and 0.7% outside Wuhan,” according to a WHO statement Feb. 24.

How do people catch it?

Scientists don’t know for sure the ways in which this coronavirus most easily spreads. But it is thought to be transmitted in respiratory droplets, the CDC says. That means close contact with others would be key to its spread.

New research out in mid-February also shows the virus can survive in human feces, suggesting it spreads through diarrhea or otherwise via unsanitary restroom conditions, in the manner of the fast-spreading norovirus responsible for the sudden, intense gastrointestinal discomfort people often call “stomach flu.”

Meanwhile, it’s not known whether or how long the virus might survive in droplets on hard surfaces, such as doorknobs or countertops. But we know the common cold virus (which is sometimes caused by a strain of coronavirus) can last “a couple hours to maybe a couple days,” depending on temperature, humidity, and other factors, says Amesh Adalja, MD, an infectious disease expert at the Center for Health Security at Johns Hopkins University. Adalja tells Elemental that the same might be true of this virus, but he thinks surfaces are not likely the main form of transmission.

For example, it’s unlikely any coronavirus would survive as a stowaway on or inside packages mailed from China to the United States. “In general, because of the poor survivability of these coronaviruses on surfaces, that’s in the range of hours, there’s likely a very, very, very low if any risk of spread from products or packaging that is shipped over a period of days or weeks in ambient temperatures,” Messonnier says.

Masks are an important line of defense against disease transmission in hospitals, but there is little research on whether they work for the general public. The key is wearing a mask that fits properly and wearing it consistently.

How can you protect yourself and others?

Prevention advice mirrors the tactics for avoiding or spreading the flu, the common cold, and other diseases:

• Frequently and correctly wash your hands, scrubbing with soap and water for at least 20 seconds, especially after using the bathroom or before preparing food. If soap is not available, hand sanitizers may be better than nothing but are not preferred.
• Avoid touching your eyes, nose, and mouth with unwashed hands.
• Clean and disinfect frequently touched objects and surfaces.

If you’re sick, stay home. Cough and sneeze into a tissue or your elbow — not your hands or into the air.

Do surgical masks help?

Masks are an important line of defense against disease transmission in hospitals, but there is little research on whether they work for the general public. The key, experts say, is wearing a mask that fits properly and wearing it consistently. “They don’t hurt and may offer some protection,” Adalja says. But if you stick an infected hand under the mask to scratch an itch, you’ve rendered the mask useless, he points out.

“We do not currently recommend the use of face masks for the general American public,” Messonnier said Jan. 31. “This virus is not spreading in your communities. While it is cold and flu season, we don’t routinely recommend the use of face masks by the public to prevent respiratory illness, and we are certainly not recommending that at this time for this novel virus.”

Should you worry about air travel or travel in general?

“Do not travel to China,” the U.S. State Department says. That’s Level 4 travel alert — the most strict.

Health officials have not advised people to worry about air travel in general, though the CDC suggests avoiding cruise ships that voyage to or within Asia. Federal officials have not suggested anyone limit domestic travel.

U.S. officials do routine health checks of anyone arriving from another country who is known to be sick, and specific coronavirus screenings are done on inbound travelers at 20 U.S. airports where people are most likely to be arriving after originating in China. These inbound travelers are all screened with a noncontact thermal device to check their temperatures, and officials look for coughing or sneezing. The passengers also answer questions about their travel, any possible symptoms, and whether they came in contact with infected people.

What are the U.S. quarantine and travel rules?

New measures effective Sunday evening, Feb. 2, have been taken to help prevent the spread of the disease, Alex Azar, Secretary of Health and Human Services, and Chairman of the President’s task force on the novel coronavirus, announced:

• U.S. citizens who’ve been in Hubei Province, the epicenter of the outbreak in China, in the previous 14 days are subject to up to 14 days of mandatory quarantine upon return, “to ensure they’re provided proper medical care and health screening.”
• U.S. citizens who’ve has been in the rest of mainland China within the previous 14 days will, upon return, “undergo proactive entry health screening at a select number of ports of entry and up to 14 days of monitored self-quarantine to ensure they have not contracted the virus and do not pose a public health risk.”
• “Foreign nationals, other than immediate family of U.S. citizens and permanent residents, who have traveled to China within the last 14 days will be denied entry into the U.S.”

What are the symptoms of coronavirus?

Some infected people have reported little to no symptoms, the CDC says. In others, symptoms include fever, cough, and shortness of breath and can range from mild to severe, causing death. A CDC spokesperson tells Elemental it’s too soon to pin down other symptoms. But a Feb. 7 Chinese study of patients hospitalized for the disease — meaning they had severe cases — found body aches in about one-third of them and nausea and diarrhea in about 10%.

Much remains to be learned about the progression of the illness, but the CDC thinks symptoms show up as quickly as two days after exposure or as late as 14 days — a range seen previously in MERS. U.S. officials now say that even before infected people have symptoms, they can pass the coronavirus on to other people. That ups the risk of a faster spread.

Recovery time is about two weeks for people with mild symptoms, and up to six weeks in severe cases, the WHO announced Feb. 24.

How can you tell coronavirus symptoms from a cold or the flu?

“You really can’t,” Adalja says. The symptoms are “indistinguishable” from those of the flu and other respiratory infections, he says. Given the high number of flu cases in the United States right now, the only reason you might suspect you have coronavirus is if you’ve traveled to China or another infected area or if you’ve come in contact with someone diagnosed with this coronavirus, Adalja says. In such cases, the CDC asks that you contact a health care provider.

Is there a vaccine?

No. Scientists at the National Institutes of Health and other agencies are working on one, but don’t hold your breath. Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases, said on January 28 that he’s cautiously optimistic there may soon be a vaccine candidate ready for phase one clinical trials. But the testing and analysis during such a trial would likely take several months before any vaccine would be ready for widespread use, he said.

Are there any treatments or therapies for this virus?

“There is no proven therapy,” but there are antiviral medications shown to work in past outbreaks, Fauci says. The CDC and other agencies are studying specimens from infected people, in lab settings, to see whether any of these treatments might be effective against this strain of the virus.

How bad could the outbreak become?

Nobody knows just yet, and health officials are loath to speculate. The potential extent of this outbreak depends on how easily it spreads between humans, and scientists haven’t fully figured that out yet.

“We are facing an unprecedented public health threat,” Messonnier said Jan. 31. “We are preparing as if this were the next pandemic, but we are hopeful still that this is not and will not be the case.” She reiterated on Feb. 21 that the virus is still not spreading within any communities in the United States, thanks in part to aggressive quarantine efforts.

However, as Elemental reported Feb. 5, some experts have been saying COVID-19 already qualifies as a pandemic, or would soon, even though there is no formal definition of a pandemic. On Feb. 24, as sudden spikes in cases were revealed in South Korea, Iran and Italy, WHO director-general Dr. Tedros Adhanom Ghebreyesus downplayed the need to use the word, which he said “may certainly cause fear.”

“WHO has already declared a public health emergency of international concern — our highest level of alarm,” Tedros said. “For the moment, we are not witnessing the uncontained global spread of this virus, and we are not witnessing large-scale severe disease or death. Does this virus have pandemic potential? Absolutely, it has. Are we there yet? From our assessment, not yet.”

Meanwhile, as of Feb. 24 COVID-19 had spread to more than two dozen countries and killed more than 2,500 people, including about two dozen outside China. “What we see are epidemics in different parts of the world,” Tedros said.

Is this the worst viral outbreak ever?

In terms of sheer numbers, no. But its impact is now looking like some notable past outbreaks.

In recent decades, two other suddenly infectious coronaviruses plagued humans. The 2003 outbreak of SARS spread to 8,098 people across four continents, killing about 10% of those infected; only eight cases were confirmed in the United States, and no deaths. MERS cropped up in humans in 2012 and has since spread to 2,494 people in 27 countries, killing about a third of its victims.

For perspective, other viruses that have crossed from animals to humans include HIV/AIDS, which has killed about 32 million people. Multiple outbreaks of Ebola, a virus carried by fruit bats and now transmitted between humans, have on average killed half of the people who contract it, but some outbreaks have reached 90% fatality rates.

Various strains of the flu virus kill between 291,000 and 646,000 people globally each year. In the United States, influenza infects between 9 million and 45 million people annually, resulting in 12,000 to 61,000 deaths each year.

A century ago, the Spanish flu pandemic of 1918–19 killed more than 50 million people in a single year (some estimates are double that figure), including 675,000 in the United States — all at a time when the global population was one-fourth of today’s number. Experts say one-third of the world’s population got the flu that year.

Coronavirus Myths & Hoaxes

Several misleading and even dangerous coronavirus myths and hoaxes are circulating on social media. “Every outbreak has its ‘infodemic’… an epidemic of rumors of false information,” says Dr, Sylvie Briand, director of WHO’s Infectious Hazard Management Department.

Here are some truths:

• Gargling with mouthwash, even if it is marketed to kill germs, will not help with this coronavirus, according to WHO
• Rinsing your nose with a saline solution has not been shown to protect against the coronavirus or any other respiratory infection
• Eating garlic may be good for you, but there is no evidence it’ll help ward off the coronavirus
• Antibiotics kill bacteria, but not viruses. Antibiotics are of no use against coronavirus
• Bleach and other household disinfectants will kill coronavirus on counters and other hard surfaces. Sesame oil will not
• Yes, coronaviruses spread in some wild animals, including bats. But there’s no evidence that eating meat sold in the United States puts you at risk
• Your dog or cat cannot spread this coronavirus

The data on global flu deaths and the travel alert have been updated.

The coronavirus outbreak is rapidly evolving. To stay informed, check the U.S. Centers for Disease Control and Prevention as well as your local health department for updates. If you’re feeling emotionally overwhelmed, reach out to the Crisis Text Line.