A newly identified coronavirus SARS-CoV-2 (formerly 2019-nCoV) has been spreading in China, and has now reached multiple other countries. Here's what you need to know about the virus and the disease it causes, called COVID-19.
Update on Wednesday, Feb. 19 (ET):
—American passengers who had been stuck on a cruise ship off the coast of Japan for nearly two weeks were evacuated on Sunday (Feb. 16) and have now arrived in the U.S. Fourteen of those passengers tested positive for COVID-19, bringing the total number of U.S. cases to 29.
—Director of hospital in Wuhan has died from COVID-19. About 1,716 medical workers have COVID-19 (1,502 of those cases in Hubei Province), and six of these workers have died, the Times reports.
—The Chinese Center for Disease Control and Prevention is reporting COVID-19 is up to 20 times more deadly than the flu, with a fatality rate of about 2.3% (in the U.S., seasonal flu's fatality rate is about 0.1%), the Times reports.
—A 61-year-old man in Taiwan with history of diabetes and hepatitis B has died from the coronavirus. He had no history of travel to Wuhan and may have been a taxi driver, the Times reported.
—About 75,282 confirmed coronavirus cases (primarily in mainland China), according to the Johns Hopkins virus dashboard.
—2,012 deaths linked to the virus. Deaths worldwide exceed those from SARS.
—About 542 individuals onboard the Diamond Princess cruise ship off Japan have tested positive for the coronavirus. There were 3,700 passengers and crew on the ship when it first docked off Japan.
—Hundreds of Americans onboard the Diamond Princess were evacuated back to the U.S. on Sunday, the Times reported. Australia, Canada and Hong Kong have said they'll evacuate their citizens as well.
—5 deaths have been linked to the virus outside of mainland China to date, including in Taiwan, the Philippines, Japan, Hong Kong and France.
—With the approval of several international organizations, the WHO has now replaced the temporary name for the disease with an official name: Corona Virus Disease, abbreviated as COVID-19.
—The International Committee on Taxonomy of Viruses has named the virus "severe acute respiratory syndrome coronavirus 2, or SARS-CoV-2," due to its genetic similarity to the virus that causes severe acute respiratory syndrome (SARS).
Number of coronavirus cases
Mainland China: 72,438
Diamond Princess ship: 542 (according to the Times)
Hong Kong: 61
South Korea: 31
United Arab Emirates: 9
Sri Lanka: 1
What's the death rate from COVID-19?
The largest study on COVID-19 cases to date provides new details on the severity of the illness, including its death rate and who is most susceptible.
The study researchers, from the Chinese Center for Disease Control and Prevention, analyzed information from 44,672 confirmed cases of COVID-19 in China that were reported between Dec. 31, 2019 and Feb. 11, 2020. Among these cases, there were 1,023 deaths, resulting in an overall death rate of 2.3%.
That's much higher than the death rate of flu, which is around 0.1% in the U.S., according to The New York Times.
However, the new study found that the death rate from COVID-19 varied by location. In Hubei Province, where the outbreak began, the death rate was 2.9%, compared with just 0.4% in other provinces — a 7-fold difference.
The study also showed that older adults have been hit hardest by COVID-19. Among those ages 80 and older, the death rate was 14.8%, compared with 8.0% for those ages 70 to 79; 3.6% for those ages 60 to 69; 1.3% for those ages 50 to 59; 0.4% for those ages 40 to 49, and 0.2% for those ages 10 to 39. No deaths have been reported among children from birth to age 9.
However, some experts have estimated that the number of COVID-19 cases could be much higher than what has been officially tracked and reported, according to the BBC. If that's the case, then the death rate could be lower than what's reported in this study.
Why did coronavirus cases spike?
On Feb. 12, the Hubei Province, where the outbreak began in Wuhan, officials have decided to consider a "clinical" diagnosis for the new coronavirus. That means these individuals who may have tested negative on the current diagnostic test (called a nucleic acid test) but show all of the coronavirus symptoms will be classified as confirmed cases. In that way, the Hubei Province Health Committee said, "patients can receive standardized treatment according to confirmed cases as early as possible to further improve the success rate of treatment."
With that new criteria, the province added 14,840 cases of coronavirus to the total in a day.
Will the coronavirus die down by the summer?
We don't know yet. Most respiratory viruses, such as flu viruses, are seasonal. We generally know when the peak of flu season will be and can expect the number of flu cases to drop down as we head toward spring and summer, said Dr. Nancy Messonnier, the director of CDC's National Center for Immunization and Respiratory Diseases in a news conference on Feb. 12. But for the new virus, "I think it's premature to assume that," she said. If this new virus behaves similarly to flu viruses, we may see less infections as spring and summer roll around. "But this is a new disease, we haven't even been through six weeks of it much less a year," Messonnier said. Though hoping the numbers will go down as warm weather approaches, "the aggressive actions we're taking are because we don't think we can count on that."
Coronavirus in the US?
As of Feb. 18, there are 29 confirmed cases of the new coronavirus in the United States. These include 14 people who were stuck on a cruise ship off the coast of Japan and arrived back in the U.S. on Feb. 16 and Feb. 17. Most of the infected passengers were taken to the University of Nebraska Medical Center in Omaha. The rest of the evacuated passengers are under quarantine at military bases in California and Texas.
Other previously-identified cases of coronavirus in the U.S. include 8 cases in California, 2 cases in Illinois, and one case each in Washington, Arizona, Massachusetts, Wisconsin and Texas.
Some person-to-person spread of SARS-CoV-2 has been seen in the U.S. among close contacts of people returning from Wuhan, but the virus is not currently spreading in the community here, according to the CDC.
Newly emerged viruses like SARS-CoV-2 are always of public health concern, according to the CDC. It's unclear how the situation with this virus in the U.S. will unfold, the agency says. Some people, such as health care workers, are at increased risk for exposure to SARS-CoV-2. But for the general American public, the immediate health risk from the virus is low at this time, the CDC says.
Coronavirus quarantine in Wuhan
Wuhan plans to round up those suspected of having the virus to be placed in isolation, in some kind of mass quarantine camps, The New York Times reported. China's Vice Premier Sun Chunlan said that city officials should go door to door to check residents' temperatures and to interview those in contact with infected individuals, the Times reported.
"Set up a 24-hour duty system. During these wartime conditions, there must be no deserters, or they will be nailed to the pillar of historical shame forever," Sun said, according to the Times.
The Times is reporting a shortage of medical supplies, coronavirus-testing kits and hospital beds due to the lockdown in the city and surrounding area, leading to people walking on foot from hospital to hospital, only to be turned away.
Who will be quarantined in the US?
Officials announced on Friday (Jan. 31) that the U.S. will be enforcing quarantines on citizens who have traveled to the Hubei Province (where the outbreak originated) in the last 14 days. If U.S. citizens have been to China in the last 14 days, they will be rerouted to one of eleven airports (see above) across the country to be screened for the new coronavirus, according to the Department of Homeland Security (DHS).
If passengers who have traveled to China are showing symptoms of the virus (which include a cough, trouble breathing or fever) they will be subject to mandatory quarantines. If passengers who have traveled to China (outside of the Hubei province) show no symptoms after being screened at one of the 11 airports, they will be re-booked to their destinations within the U.S. and asked to self-quarantine at home, according to the DHS.
Other travelers who haven't been to China but are found to be on the same flight of passengers that have been to China might also be rerouted to one of the 11 airports, according to the DHS. What's more, in general "foreign nationals" who have traveled to China in the past 14 days won't be allowed in the U.S.
Hundreds of U.S. citizens who were evacuated from Wuhan are currently under mandatory quarantine at several U.S. military bases.
Does the coronavirus have an official name?
On Feb. 11, WHO Director-General Tedros Adhanom Ghebreyesus announced the official name of the new disease caused by the novel coronavirus: Corona Virus Disease, abbreviated as COVID-19. "Having a name matters to prevent the use of other names that can be inaccurate or stigmatizing. It also gives us a standard format to use for any future coronavirus outbreaks," Ghebreyesus said.
WHO discourages naming new viruses after geographic locations, people, species or classes of animals or foods, according to the organization's Best Practices for the Naming of New Human Infectious Diseases. Rather, WHO encourages use of descriptive terms of a disease, such as "respiratory disease" and "neurologic syndrome," as well as "severe" or "progressive." The organization also says that if a pathogen is known, it should be used as part of the disease's name.
The International Committee on Taxonomy of Viruses is tasked with giving the virus an official name. On Feb. 11, the committee said the virus will be known as "severe acute respiratory syndrome coronavirus 2," or SARS-CoV-2, due to its genetic similarity to the virus that causes severe acute respiratory syndrome (SARS), according to Science Magazine.
What is a coronavirus?
Coronaviruses are a large family of viruses that can cause respiratory illnesses such as the common cold, according to the Centers for Disease Control and Prevention (CDC). Most people get infected with coronaviruses at one point in their lives, but symptoms are typically mild to moderate. In some cases, the viruses can cause lower-respiratory tract illnesses such as pneumonia and bronchitis.
These viruses are common amongst animals worldwide, but only a handful of them are known to affect humans. Rarely, coronaviruses can evolve and spread from animals to humans. This is what happened with the coronaviruses known as the Middle East respiratory syndrome coronavirus (MERS-CoV) and the severe acute respiratory syndrome coronavirus (SARS-Cov), both of which are known to cause more severe symptoms.
Where did the new coronavirus come from?
Since the virus first popped up in Wuhan in people who had visited a local seafood and animal market (called the Huanan seafood market), officials could only say it likely hopped from an animal to humans. In a new study, however, the researchers compared SARS-CoV-2 (formerly 2019-nCoV) genetic sequence with those in a library of viral sequences, and found that the most closely related viruses were two coronaviruses that originated in bats; both of those coronaviruses shared 88% of their genetic sequence with that of SARS-CoV-2.
Based on these results, the authors said the SARS-CoV-2 likely originated in bats. However, no bats were sold at the Huanan seafood market, which suggests that another yet-to-be-identified animal acted as a steppingstone of sorts to transmit the virus to humans.
A previous study suggested snakes, which were sold at the Huanan seafood market, as a possible source of the new virus. However, some experts have criticized the study, saying it's unclear if coronaviruses can infect snakes.
How does the coronavirus spread between people?
Researchers are still working to understand exactly how SARS-CoV-2 spreads. But in general, the The most common way coronaviruses spread is through respiratory droplets produced from coughs and sneezes, according to the CDC. Tests have also found the virus present in patients' stool, suggesting it may be able to spread through fecal contamination. However, it is still unclear whether people can catch the virus by touching contaminated surfaces, the CDC says.
Deaths from coronavirus outside China
As of Feb. 13, there have been three reported deaths from the new coronavirus outside of China. These include the deaths of a 44-year-old man in the Philippines, a 39-year-old man in Hong Kong, and a woman in her 80s in Japan.
Could this virus cause a pandemic?
In order for this virus, or any, to lead to a pandemic in humans, it needs to do three things: efficiently infect humans, replicate in humans and then spread easily among humans, Live Science previously reported. Right now, its unclear how easily the virus spreads from person to person.
To determine how easily the virus spreads, scientists will need to calculate what's known as the "basic reproduction number, or R0 (pronounced R-nought.) This is an estimate of the average number of people who catch the virus from a single infected person, Live science previously reported. A study published Jan. 29 in the New England Journal of Medicine (NEJM) estimated an R0 value for the new coronavirus to be 2.2, meaning each infected person has been spreading the virus to an average of 2.2 people. This is similar to previous estimates, which have placed the R0 value between 2 and 3. (For comparison, SARS initially had an R0 of around 3, before public health measures brought it down to less than 1.)
In general, a virus will continue to spread if it has an R value of greater than 1, and so public health measures to stem the outbreak should aim to reduce R0 to less than one, the authors of the NEJM paper said.
On Jan. 30, the World Health Organization (WHO) declared that the new coronavirus outbreak is a public health emergency of international concern. The main reason for the declaration is concern that the virus could spread to countries with weaker health systems, WHO said.
How does coronavirus compare to SARS and MERS?
As of Feb. 9, more people had died from the new coronavirus than from SARS — which killed 774 individuals worldwide, according to The New York Times.
MERS and SARS have both been known to cause severe symptoms in people. It's unclear how the new coronavirus will compare in severity, as it has caused severe symptoms and death in some patients while causing only mild illness in others, according to the CDC. All three of the coronaviruses can be transmitted between humans through close contact.
MERS, which was transmitted from touching infected camels or consuming their meat or milk, was first reported in 2012 in Saudi Arabia and has mostly been contained in the Arabian Peninsula, according to NPR. SARS was first reported in 2002 in southern China (no new cases have been reported since 2004) and is thought to have spread from bats that infected civets. The new coronavirus was likely transmitted from touching or eating an infected animal in Wuhan.
During the SARS outbreak, the virus killed about 1 in 10 people who were infected. The death rate from COVID-19 isn't yet known. In the beginning of an outbreak, the initial cases that are identified "skew to the severe," which may make the mortality rate seem higher than it is, Alex Azar, secretary of the U.S. Department of Health and Homeland Security (HHS), said during a news briefing on Tuesday (Jan. 28). The mortality rate may drop as more mild cases are identified, Azar said.
Currently, most of the patients who have died from the infection have been older than 60 and have had preexisting conditions.
What are the symptoms of the new coronavirus and how do you treat it?
Symptoms of the new coronavirus include fever, cough and difficulty breathing, according to the CDC. It's estimated that symptoms may appear as soon as two days or as long as 14 days after exposure, the CDC said. The NEJM study published on Jan. 29 estimated that, on average, people show symptoms about five days after they are infected.
There are no specific treatments for coronavirus infections and most people will recover on their own, according to the CDC. So treatment involves rest and medication to relieve symptoms. A humidifier or hot shower can help to relieve a sore throat and cough. If you are mildly sick, you should drink a lot of fluids and rest but if you are worried about your symptoms, you should see a healthcare provider, they wrote. (This is advice for all coronaviruses, not specifically aimed toward the new virus).
There is no vaccine for the new coronavirus, but researchers at the U.S. National Institutes of Health confirmed they were in preliminary stages of developing one. Officials plan to launch a phase 1 clinical trial of a potential vaccine within the next three months, Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases, said in a news conference on Jan. 28.
Researchers are also working on gathering samples of the virus to design a therapy that will train patients' immune cells to detect and destroy the virus, Facui said.
How can people protect themselves and others?
The best way to prevent infection with COVID-19 is to avoid being exposed to the virus, according to the CDC. In general, the CDC recommends the following to prevent the spread of respiratory viruses: Wash your hands often with soap and water for at least 20 seconds; avoid touching your eyes, nose, and mouth with unwashed hands; avoid close contact with people who are sick; stay home when you are sick and clean and disinfect frequently touched objects and surfaces.
People who traveled to China and became sick with fever, cough or difficulty breathing within the following two weeks should seek medical care right away, and call ahead to inform medical staff about their recent travel, the CDC said.
The CDC does not recommend face masks for people who are well and without symptoms. The agency does recommend face masks for people who show symptoms of the virus and those taking care of someone sick with the virus (including health care workers).
Jeanna Bryner, Rachael Rettner, Yasemin Saplakoglu and Nicoletta Lanese contributed reporting.
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Originally published on Live Science.