- The outbreak has spread to 10 other countries, including the US .
- The virus jumped from animals to people in December, likely at a Chinese wet market where live and dead animals were being sold.
- SARS was also a coronavirus. That outbreak killed 774 around the world between 2002 and 2003, and SARS also emerged in a wet market.
- Here's how the two viruses compare.
- Visit Business Insider's homepage for more stories .
The virus, which is marked by fevers and pneumonialike symptoms, likely originated in a wet market in the city of Wuhan. The markets put shoppers, vendors, and live and dead animals in close proximity, which raises the risk of a disease outbreak, since coronaviruses are zoonotic diseases (meaning they can jump from animals to people).
This outbreak has conjured a sense of dja vu for some people who remember the severe acute respiratory syndrome (SARS) outbreak that started in November 2002. That was also a coronavirus, and it also jumped to people from animals in the wet markets. SARS emerged in Guangdong and infected 8,098 people over the course of eight months, killing 774 . Patients experienced fevers, headaches, and a type of deadly pneumonia that could cause respiratory failure.
Experts called SARS "the first pandemic of the 21st century," since it spread across 29 countries. The disease hasn't been seen in humans since July 2003.
So far, experts say, concerns that the Wuhan coronavirus is the next SARS are overblown. The two virus' symptoms and origins may be comparable, but their severity is not.
The new coronavirus appears to be less severe than the SARS, former FDA Commissioner Scott Gottlieb told CNBC on Friday. It might be more contagious, however, given that the outbreak is spreading faster than SARS did.
Eric Toner, a senior scientist at John Hopkins University offered a similar assessment: "An initial first impression is that this is significantly milder than SARS," he told Business Insider. "That's reassuring. On the other hand, it may be more transmissible than SARS, at least in the community setting."
Here are some of the crucial differences between this outbreak and the SARS one 17 years ago.
The first report of the Wuhan coronavirus came on December 31, 2019. Wuhan is a city of 11 million people in the central province of Hubei, China.
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SARS originated in the Guangdong province in southeastern China, near Hong Kong.
According to the World Health Organization (WHO), 50% of people impacted by SARS were age 65 or older, while the other half of infected patients varied widely in age.
PETER PARKS/AFP via Getty Images
So far, experts report that the median age of those who have died from the Wuhan coronavirus is around 75. Many of these individuals had other health issues like high blood pressure, diabetes, and Parkinson's disease.
Adrian Hyzler, chief medical officer at Healix International, told Business Insider that children, elderly people, pregnant women, and those who are immuno-compromised are more susceptible to the Wuhan coronavirus' most severe complications.
SARS didnt spread as fast in its first three weeks as the coronavirus has, according to the WHO.
It took almost four months for SARS to spread to 1,000 people. The Wuhan coronavirus has infected more than 1,200 people in just 25 days.
"One person whos been infected can suddenly infect 10, 20, 30 people," Hyzler said of the coronavirus. "So this is what makes it much more contagious and much more of a problem."
However, SARS was far more deadly, with a fatality rate of 9.6%. The new coronavirus fatality rate has not yet been determined with accuracy, but it seems closer to 3% or 4% so far.
One reason SARS spread to so many places around the world is that Chinese authorities initially attempted to hide the outbreak from the World Health Organization.
AHMAD YUSNI / AFP) (Photo by AHMAD YUSNI/AFP via Getty Images
The Chinese government didn't inform the WHO about SARS until February 14, 2003. According to The Sydney Morning Herald , doctors in Beijing were ordered by authorities to hide SARS patients from WHO officials during inspections.
During the initial stages of that outbreak, the Chinese government also concealed information from the public, limiting mitigation efforts and exacerbating the spread of disease.
Liu Heng, an adviser to Chinas cabinet, told Reuters that this time around, China announced the outbreak to the public much more immediately.
"We are doing much better now ... We are paying greater attention to preventing the epidemic," he said on Wednesday.
Chinese public-health experts also worked to quickly share the Wuhan coronavirus genetic information with researchers around the globe.
Agence France Presse
"The speed with which this virus has been identified is testament to changes in public health in China since SARS and strong global coordination through the WHO," Jeremy Farrar, a British infectious diseases specialist who also worked on combating SARS, told Reuters.
By contrast, it took four months for SARS' genome to be published.
By sharing information about the new coronavirus genome, scientists have been able to work together to analyze how the illness is spreading and mutating.
That work also helps experts track down which animal the coronavirus jumped from.
In the case of SARS, and probably this coronavirus outbreak too, bats were the original hosts. They then infected other animals via their poop or saliva, and the unwitting intermediaries transmitted the virus to humans.
"Bats and birds are considered reservoir species for viruses with pandemic potential," Bart Haagmans, a virologist at the Erasmus Medical Center in Rotterdam, Netherlands, told Business Insider.
SARS jumped from bats to weasel-like mammals called masked palm civets, then to humans.
According to a group of scientists who edit the Journal of Medical Virology, the culprit spreading the Wuhan coronavirus could be the Chinese cobra, but that has yet to be confirmed.
An analysis showed that the genetic building blocks of the Wuhan coronavirus closely resembled that of snakes.
Here are five viruses that most likely came from bats, and how the outbreaks compare.
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Researchers traced SARS to a population of horseshoe bats in China's Yunnan province. These bats lived in a cave just 1.1 kilometer from the nearest village.
Another major difference between the SARS outbreak and the current outbreak is that this time, Chinese authorities quickly instituted travel lock-downs.
Authorities quarantined Wuhan on Thursday at 10 a.m. local time, halting all public transportation, including city buses, trains, and ferries. The order prevents any buses or trains from coming into or leaving the city and grounds all planes at the Wuhan airport.
Just before midnight on Thursday, the city of Huanggang went into lockdown as well, as authorities closed subway and train stations. By the following day, 10 additional cities Chibi, Enshi, Ezhou, Huangshi, Suizhou, Qianjjiang, Xianning, Xiantao, Yichang, and Zhijiang had followed suit with their own travel restrictions.
Tedros Adhanom Ghebreyesus, the director-general of the World Health Organization, said these efforts to quarantine cities will help Chinese authorities control the virus spread and "minimize the chances of this outbreak spreading internationally."
Kevin Frayer/Getty Images
"What they're doing is a very, very strong measure, and with full commitment," Ghebreyesus said in press conference on Wednesday.
These restrictions affect about 33 million people in China.
When it came to SARS, it took at least four months for officials to institute any quarantine measures.
Anthony Fauci, a disease expert at the National Institutes of Health, told CNBC that China is "doing much better this time" than with SARS .
Neither SARS nor the Wuhan coronavirus has a vaccine.
"If Wuhan were to explode, a vaccine best-case scenario is three-quarters of a year, if not longer," Vincent Munster, a virologist at the Rocky Mountain Laboratories, told Business Insider.
Several companies, including Moderna, Novavax, and Inovio, have announced preliminary vaccine development plans . But vaccine development has historically been an arduous, multi-year process (the Ebola vaccine took 20 years to make). None of the companies provided expected timelines to get their vaccines to market.
The Wuhan coronavirus, unlike SARS, isnt considered a pandemic.
AP Photo/Kin Cheung
The World Health Organization has not declared it a global public-health emergency, either.
- The flu is a far bigger threat to most people in the US than the Wuhan coronavirus. Here's why.
- Wuhan, China, and at least 11 other cities have been quarantined as China attempts to halt the spread of the coronavirus. That's about 33 million people on lockdown.
- The outbreaks of both the Wuhan coronavirus and SARS started in Chinese wet markets. Photos show what the markets look like.
SEE ALSO: The flu is a far bigger threat to most people in the US than the Wuhan coronavirus. Here's why.