What you need to know about the new coronavirus

A new type of virus that is thought to have originated in a Chinese seafood market has infected hundreds of people in at least seven countries around the world, raising fears of a global pandemic. At least 17 people have died, according to authorities in China and surrounding countries.

Here’s what you need to know about the virus, known in scientific parlance as 2019-nCoV:

What is it, and where did it come from?

The virus is a strain of coronavirus, a large family of pathogens that usually live in animals such as cats, bats and camels. Occasionally, they can jump between animals and humans, a process called zoonosis. Some coronaviruses are harmless to humans; you probably have a few of those in your system right now. Others can produce nothing more serious than a common cold, while the worst can lead to pneumonia.

The current virus appeared in December among people who were exposed to wildlife at the Huanan Seafood Wholesale Market in Wuhan, China, a city of about 9 million residents halfway between Beijing and Hong Kong. From there, it has spread to Thailand, South Korea, Japan, Taiwan and the United States, and health authorities in Mexico are investigating a possible case in Reynosa: a 57-year-old molecular biology professor who recently returned from Wuhan.

As of Wednesday afternoon, the World Health Organization had reported 555 cases and 17 deaths. 

A part of the effort to combat and contain new viruses is to understand where they came from in the first place — to identify the animal host from which the virus jumped to humans. New research published Wednesday in the Journal of Medical Virology suggests the virus is a combination of a coronavirus first identified in bats and another unknown coronavirus, one that researchers say looks like it came from a snake.

What has made the virus break out beyond the wholesale market is its apparent ability to transmit between humans, the same way we transmit the influenza virus.

Wait, it’s in the United States?

Yes. A man in his mid-30s was admitted to a hospital in Everett, Wash., over the weekend after seeking treatment for pneumonia-like symptoms. The state Department of Health said Tuesday he is in good condition and hospitalized out of an abundance of caution.  

The Centers for Disease Control and Prevention (CDC) said Tuesday it sees low risk of the virus spreading so far.

How does it spread? 

That’s not entirely clear yet.

At the beginning of the outbreak, everyone who caught the virus was associated in some way with the wholesale market. That suggested the virus was probably only spreading from animals to people. But recent cases have occurred among people who did not visit the market, suggesting that there is at least some human-to-human transmission. It’s not clear how common or easy those human-to-human transmissions are.

How deadly is it?

We don’t entirely know yet, and we won’t know until more data comes in. Seventeen deaths out of 555 cases would mean a 3 percent mortality rate. That’s a little more than the estimated 2.5 percent mortality rate caused by the Spanish Flu in 1918, the last time the world faced a truly disastrous global pandemic. But it’s nowhere near as deadly as diseases like the bubonic plague, hantavirus, Marburg or Ebola.

Some patients infected with the coronavirus circulating today showed relatively minor symptoms and have already been discharged from the hospital, according to the CDC.

But don’t miss the broader perspective: Even if the Wuhan coronavirus spreads to as many people as were infected by the Ebola outbreak in West Africa in 2014-2015, or the SARS outbreak from the early 2000s (more on that one in a minute), other diseases are far more deadly. The CDC said the flu virus that circulated around the world last year killed an estimated 57,000 Americans. 

Which is a good time to remind you to get your flu shot. This year’s flu has already killed an estimated 2,100 people in America, and the flu is spreading more rapidly now than it has in average years. So, to reiterate, get your flu shot. Especially if you live or work around young children or the elderly. It matters. 

Is it likely to spread?

Sadly, yes. The European Center for Disease Prevention and Control (ECDC) — the EU’s version of the CDC — said in an assessment Wednesday that the potential for wider spread is high. Both the ECDC and the CDC said they see low risk of spread through the EU or the United States, but they expect it to be wider spread among Asian nations where residents are more likely to travel to Wuhan.

The Chinese government is most concerned about the virus spreading in the next few weeks, during and after the nation celebrates the Chinese Lunar new year this coming weekend. Millions of Chinese people are expected to travel around the country during the annual holiday to visit friends and family, giving the virus opportunities to spread.

Has the world seen anything like this before?

Yes. The most recent major coronavirus outbreak came early last decade, when Middle East respiratory syndrome — MERS — broke out in Saudi Arabia, the United Arab Emirates and a few other Middle Eastern countries. A few years later, about 200 people in South Korea were struck by the MERS virus. All told, the World Health Organization (WHO) has reported just under 2,500 MERS cases since 2012, and 858 deaths, or a mortality rate of about 34 percent. 

In the early 2000s, another coronavirus called severe acute respiratory syndrome, or SARS, broke out in China’s Yunan Province. SARS eventually infected about 8,300 people in 17 countries, and 775 people died, for a mortality rate of about 9 percent. Of the 27 people in the United States who caught SARS, none died. 

What are public health officials doing about it?

A lot. The Chinese government faced harsh criticism in the early 2000s for hiding the spread of SARS, and this time they are acting much more transparently. Chinese President Xi Jinping has called for “all-out efforts” to stop the virus’s spread, and Premier Li Keqiang has ordered local governments to identify and report cases and to work with the World Health Organization, according to the country’s health ministry. The wholesale market where the virus originated was shuttered weeks ago. 

It took about a week for Chinese health officials to isolate the strain of the new virus, and once they did they uploaded its sequence to a global public health research database, giving health officials around the world the data they need to diagnose cases — and, hopefully, giving scientists around the world the chance to begin researching a vaccine or a treatment.

Using that data, the CDC has already developed a real-time reverse transcription polymerase chain reaction test — or, in plain English, a test that can identify and diagnose the Wuhan coronavirus in patients. The test is only available at CDC headquarters in Atlanta, but they hope to share it through an international resource portal in the coming days and weeks.

But treatment may be a long way off: There still are no effective treatments or vaccines for SARS, a virus first identified almost two decades ago. 

Researchers in China and Thailand have sequenced 19 strains of the virus in different patients, an impressively fast pace, and those who worry about global public health are taking heart in the fact that the countries affected are sharing so much data so transparently. 

In the United States, the CDC has set up monitoring posts to screen visitors or Americans traveling into the country from Wuhan. The federal government, through the Federal Aviation Administration, can route those travelers through just five airports — in Los Angeles, San Francisco, New York, Chicago and Atlanta — no matter where or whether they connect along the way.

The U.S. set up a similar system back in 2014-2015, during the Ebola outbreak in West Africa. Then, travelers from Liberia, Guinea and Sierra Leone were routed through just five airports where CDC screeners had set up monitoring checkpoints.

Other countries have taken similar steps. Wuhan on Wednesday announced it would temporarily close its airport and railway stations to departing passengers. Britain will screen travelers coming through London’s Heathrow Airport, and Japan, Hong Kong, Thailand, South Korea, Singapore, Italy, Australia and India are all screening passengers.

So, how likely am I to get the virus?

Even if you make a habit of visiting seafood wholesale markets in Wuhan, you’re extremely unlikely to get the coronavirus. The virus may spread further, but don’t panic. You should be much more worried about a virus you are more likely to contract — like influenza. 

So, to reiterate: Get your flu shot.