Only three and a half weeks ago, China announced the outbreak of a mysterious new virus in the city of Wuhan involving a group of people who’d been exposed to animals at a local food market.
Flash-forward to Thursday: The number of cases of 2019-nCoV, as the virus is known, has leaped to more than 650, and there are sick people in at least seven other countries.
That includes the first case in the United States.
A man in his 30s in Washington state tested positive for 2019-nCoV after being hospitalized with pneumonia last week, according to a Centers for Disease Control and Prevention (CDC) briefing Tuesday. The patient, who is currently in good condition, had recently traveled to Wuhan, China — the epicenter of the outbreak — returning to Seattle on January 15.
“Now compared to 24 hours ago, I’m more concerned about how infectious it is,” said Tom Frieden, the former director of the CDC. “If the sustained human transmission and a high rate of severe illness are confirmed, then it clearly is an event of international concern.”
With information about 2019-nCoV — and its risk of spreading — evolving by the hour, we’ve answered basic questions about the outbreak here. We’ll be updating this story as more information becomes available.
1) How did this outbreak start?
The outbreak was first reported to the World Health Organization by Chinese officials on December 31 in Wuhan, a city of 11 million in Hubei province. At that point, cases centered on Wuhan’s Huanan South China Seafood Market. Local health officials reported then that patients with the virus were “mainly business staff and purchasers” at the market, where vendors peddle seafood as well as animals such as birds and rabbits.
Scientists in China quickly ruled out known pathogens as the likely cause. And the leading hypothesis then was that a yet-to-be-identified novel virus had spread to humans from one of the animals in the market.
By January 9, the state broadcaster, China Central Television, reported a major discovery: a new virus, known as 2019-nCoV. Many of the people who had become ill tested positive for 2019-nCoV. Two days later, Chinese scientists shared the genetic sequence of the new virus, and the WHO applauded China’s efforts, since authorities appeared to be sharing information readily. (This transparency was a contrast to the SARS outbreak of 2003, when China was heavily criticized for withholding information about the outbreak for too long. The virus eventually killed 774 people and infected more than 8,000.)
While Chinese authorities still believe the 2019-nCoV outbreak may have started at the market — with animals spreading the virus directly to humans — on January 20, they confirmed that human-to-human transmission is also happening. On January 21, the WHO’s Western Pacific Regional Office said on Twitter that the spread may involve “sustained” human-to-human transmission, meaning the virus can transmit easily from one person to the next and then onward to others. Knowing that, “the scope of this outbreak expands massively,” Peter Daszak, the president of EcoHealth Alliance, a US global health research organization working in China, told Vox.
2) How many people are sick? How many have died?
As of January 23, at least 639 people had fallen ill across China — including in Wuhan, Shanghai, Guangdong, Hong Kong, and Beijing. To get the latest numbers, check this website built by researchers at Johns Hopkins; it’s collecting data from various sources: the WHO, the CDC, the National Health Commission of the People’s Republic of China (NHC), and two other sites. (The map is embedded below.)
Additional cases have turned up in travelers to the US, Thailand, Japan, Taiwan, Singapore, Vietnam, and South Korea. The Philippines and Australia are monitoring suspected cases, and a total of 18 people have died.
But the real toll may be much higher.
Hong Kong- and London-based researchers, who have modeled the outbreak’s potential, suggest there are likely many more undetected cases — from 1,300 to more than 4,000. That’s in Wuhan alone. And the risk of rapid spread is heightened, as hundreds of millions start to travel this week for China’s Lunar New Year on January 25.
3) How is the world responding?
Chinese authorities first warned people to stop traveling in and out of Wuhan, and then said they would put the city under quarantine beginning January 23, suspending public transport within Wuhan, and canceling flights and trains leaving the city. It was an extraordinary move given that Wuhan has a population of 11 million, more people than New York City. By the evening of January 23, quarantine measures had expanded to two additional cities about 50 miles east of Wuhan — Huanggang and Ezhou — effectively stifling the movement of another eight million people.
According to the New York Times, the government said the quarantine was needed to “effectively cut off the transmission of the virus, resolutely curb the spread of the epidemic, and ensure the safety and health of the people.” (Side note: The evidence for travel restrictions during outbreaks shows, counterintuitively, that they don’t actually do much to stop the spread of disease.)
Health officials in China and the region are also scrambling to find cases through screening at transportation hubs and follow up with the contacts of those infected with the virus — an effort that’s supported by the WHO and experts from other countries, including the US.
In the US, the CDC — along with the Homeland Security Department’s Customs and Border Protection — began screening travelers from Wuhan for the virus at US airports on January 17, and all travelers from the city will be funneled through airports that are looking out for cases.
4) What do we know about the first US patient?
The patient’s name hasn’t been released, but we know he’s a resident of Snohomish County in Washington state. We also know he recently traveled to Wuhan, returning to Seattle on January 15, two days before airport screening started (though the man didn’t have symptoms yet). By January 19, he reached out to health care providers to report his symptoms and travel history. They suspected 2019-nCoV.
That day, doctors tested him to see if the virus might be causing the illness, and sent his specimens to CDC in Atlanta. By January 20, health officials confirmed he had indeed been infected with 2019-nCoV. The man is currently being treated for mild pneumonia at Providence Regional Medical Center in Everett, Washington. He told officials he didn’t visit markets in Wuhan, or have any contact with sick people. The CDC and health officials in Washington are starting to do contact tracing to suss out if the man transmitted the virus to anyone else in the US.
5) How easily does this virus spread?
We don’t yet know the exact way the virus is spreading or how easy it is to catch 2019-nCoV. But we do know it’s part of a large family of viruses called coronaviruses, which mostly infect mammals, including bats. Coronaviruses attack the respiratory system, sometimes targeting the cells deep within the lungs. Only seven, including 2019-nCoV, SARS, and MERS, have evolved to infect humans.
According to the CDC, human coronaviruses are most commonly passed via:
- The air through coughing and sneezing
- Close personal contact, including touching and shaking hands
- Touching an object or surface with the virus on it, then touching your mouth, nose, or eyes before washing your hands
- And rarely, through fecal contamination
We also know at least 15 health care workers have been infected. “It’s unusual to get health care worker infections in outbreaks,” explained Tom Inglesby, director of the Center for Health Security of the Johns Hopkins Bloomberg School of Public Health. “It’s always a sign of alarm when that happens,” he added, because it means the virus may be easily transmitted, even in settings where people are taking precautions.
6) What are the symptoms?
Two of the seven coronaviruses that infect humans, SARS and MERS, can cause severe pneumonia and even death. The rest lead to milder symptoms, like a common cold. Right now it’s not clear where 2019-nCoV falls on that spectrum.
So far, the main symptoms reported are fever followed by difficulty breathing, the WHO said. Chest X-rays have shown signs of pneumonia in both lungs. (A quick refresher: Pneumonia is an infection in the lungs that can be caused by a variety of organisms — bacteria, fungi, viruses, even parasites. In this case, 2019-nCoV is causing the infection and leading the lungs’ air sacs to become inflamed and fill up with fluid or pus instead of air.)
Among the infected, most are still being treated in the hospital and at least 18 people have died. (So far, the deaths have occurred in mostly older people with underlying health conditions.)
It’s possible there are many more people with the virus out there who have very mild symptoms or who are asymptomatic, said Dr. Jeremy Farrar, director of the Wellcome Trust, a research charity focused on global health. If that’s the case, and there are thousands carrying 2019-nCoV while only a few people have died, this outbreak will look milder.
It’s also possible this virus winds up behaving like SARS, said Inglesby, which kills about one in 10 patients infected. With SARS, “We saw substantial spread in health care settings where health care workers became ill during care for patients,” for example. “This is a very serious outbreak with the potential for widespread transmission.”
7) What’s the likelihood this becomes a global public health emergency?
The potential for this virus to spread further is so great that the WHO gathered an expert on Wednesday to decide whether the emergence of 2019-nCoV constitutes a global public health emergency. On Thursday, WHO’s Director-General, Tedros Adhanom Ghebreyesus, announced it doesn’t yet constitute one.
Formally, a public health emergency of international concern, or PHEIC — pronounced “fake” — is defined as “an extraordinary event which is determined to constitute a public health risk to other States through the international spread of disease and to potentially require a coordinated international response.” In reality, it’s a political tool the WHO uses to sound the alarm about a serious disease that has caught the world off guard and put people’s health in danger. It’s meant to draw countries’ immediate attention, to galvanize resources, and stop the disease from spreading further across borders.
A key consideration in declaring a PHEIC is whether the disease threat is dire enough to risk countries enacting travel and trade restrictions. Declarations can be devastating to local economies and are often associated with economic losses. So they’re not taken lightly. In fact, the WHO has only declared a public health emergency five times since the International Health Regulations, which govern global health emergency responses, were enacted in 2007.
The first time was in 2009, with the outbreak of the H1N1 swine flu pandemic. The second time was in May 2014, when polio seemed to surge again, threatening the eradication effort. The third time, in August 2014, came as the Ebola outbreak in West Africa was growing out of control. The fourth was related to Zika in 2016. And the fifth, in 2019, was another outbreak of Ebola that’s ongoing in the Democratic Republic of the Congo.
8) How worried should I be about a pandemic?
There are too many unknowns to say. We don’t know which animal carries this virus, how exactly it spreads, how easily it spreads among people, how deadly it is, or the range of symptoms it can cause. We don’t know how vulnerable the people who have died were to pneumonia. (So far, at least several appear to have been elderly with underlying health conditions.)
Even so, the fact that cases are already turning up in so many countries — mere weeks after this outbreak was first declared — suggests we should brace ourselves for an escalation. “The risk is that infected people might not get noticed at the border before they get sick, and then spread the virus to others, seeding further outbreaks,” Daszak said.
For now, the CDC has stated that “the risk from 2019-nCoV to the American public is deemed to be low.” “There is new information hour by hour, day by day, that we are tracking and following closely,” said Nancy Messonnier, director of the CDC’s National Center for Immunization and Respiratory Diseases.
There are likely to be several more cases — in the US and beyond, she warned. That doesn’t, however, mean American officials expect the US to be inundated with dozens of patients or that the virus will spread broadly in the country. It’s the major cities in and around China that are most at risk, according to a paper posted on January 14 in the Journal of Travel Medicine. The top travel destinations out of Wuhan — and most at risk of spread of this infection — include Bangkok, Hong Kong, Tokyo, and Taipei.