Europe is the new epicenter of coronavirus, and the US may be next

Follow all of PopSci’s COVID-19 coverage here, including travel advice, pregnancy concerns, and the latest findings on the virus itself.

A version of this article was originally published on January 27. It has been updated.

A new coronavirus first identified in Wuhan, China, has global health agencies on high alert—and is causing no small amount of anxiety around the world. As of March 11, the World Health Organization is now describing the situation as a pandemic, though the change in designation isn’t cause for panic. It’s a recognition of the global spread of the virus, but because there’s no technical definition of “pandemic,” this doesn’t change the way the WHO is tackling the problem.

“Caution is appropriate,” U.S. Surgeon General Jerome Adams said on March 2. “Preparedness is appropriate. Panic is not.”

Here’s everything experts know about COVID-19 so far. We’ll keep this article updated as more information becomes available.

What is COVID-19?

The disease colloquially referred to as the coronavirus but officially dubbed COVID-19 is still poorly understood. The first cases appeared in December in the Chinese city of Wuhan, and likely came from some non-human animal host, though the exact species and where it came into contact with humans has yet to be identified. Scientists have broadly criticized a recent study suggesting snakes might be the source. Another claim from Chinese state media—that pangolins, which are frequently poached for their scales, could have passed the virus from bats to humans—lacks robust evidence as well. Conspiracy theories about the origin of the virus have run so rampant that on February 18, a group of 27 international public health experts published a letter in The Lancet condemning rumors and speculation.

Coronaviruses are a family of viruses that often cause mild respiratory symptoms (the common cold is one of them), but some can cause serious illness. Severe acute respiratory syndrome coronavirus (SARS-CoV), which jumped from bats to humans in China’s Guangdong Province in 2002, infected more than 8,000 people worldwide and killed at least 774.

Where has the novel coronavirus been identified?

Cases have been confirmed in at least 118 countries worldwide, with most of the cases outside of mainland China concentrated in Italy, Iran, and South Korea. The US, France, Germany, Japan, and Spain also each have more than 1,000 cases. The UK has more than 500, and Canada, Australia, Singapore, Iceland, and Israel all have more than 100.

How many people have COVID-19?

As of March 13, there were more than 135,400 confirmed cases, according to the World Health Organization (WHO). While the majority of cases—more than 80,900 of them—have been within mainland China, there are now more than 7,000 cases in South Korea, more than 10,000 in Iran, and more than 15,000 in Italy.

South Korea has opened more than 100 testing sites, including a drive-through designed to make the process faster (and minimize dangerous exposure for healthcare workers doing the testing). On Friday, the country reported the first indications that new infections may be slowing down.

Italy has implemented nationwide lockdowns on an unprecedented scale. The country’s high percentage of elderly citizens—second in the world only to Japan—has officials concerned that death rates will be high, and the New York Times reports that overloaded hospitals have started to have to make decisions about who is worth even attempting to treat.

Officials in Iran have confirmed 429 deaths. State media reported earlier this month that 23 members of parliament—nearly 10 percent of the country’s lawmakers—have tested positive for the virus. The WHO has called Iran’s outbreak “very worrisome.” Political unrest, porous borders, and inadequate access to healthcare make Iran a particularly dangerous place for the virus to spread.

“It is a recipe for a massive viral outbreak,” Peter Piot, director of the London School of Hygiene and Tropical Medicine and the former founding executive director of the Joint United Nations Program on H.I.V./AIDS, told The New York Times. Iran appears to have a much higher fatality rate than other countries experiencing outbreaks, which may be due to a combination of factors, namely, an under-reporting in the number of mild, cold-like cases, and a lack of access to quality medical care. On March 1 the surge in reported new cases caused a sharp drop in the country’s apparent fatality rate, but it’s still more than double the global average.

While COVID-19 has now gained footholds in more than 100 countries, its spread in China continues. And though Chinese cases are still on the rise, the rate of new confirmations has finally slowed down. Outside of Hubei Province, where COVID-19 originated, the majority of new cases are now coming from people who contracted the virus while traveling internationally.

How many cases of COVID-19 have been confirmed in the U.S.?

As of March 13, there were more than 1,600 cases of the novel coronavirus reported in the states. The majority of these cases are due to “community spread,” meaning that patients didn’t travel to countries with large outbreaks or have close contact with anyone who knowingly caught COVID-19 internationally. Instead, they are suspected to have caught the virus while going about their daily lives—suggesting it’s circulating in communities around the US and has been for some time.

This doesn’t come as a surprise: At a press briefing on February 25, the CDC’s National Center for Immunization and Respiratory Diseases Director Nancy Messonnier said that the spread of COVID-19 in the US appeared “inevitable.” Because COVID-19 causes mild, cold-like symptoms in most patients, health officials have long voiced concerns that it could spread far and wide before making someone seriously ill and prompting testing.

“Ultimately we expect we will see community spread in the United States,” Messonnier said in February. “It’s not a question of if this will happen but when this will happen and how many people in this country will have severe illnesses.”

Health officials now suspect that Washington, where most of the deaths from COVID-19 have occurred, has been quietly harboring the disease for weeks. A surge of confirmed cases in California, Oregon, and New York suggest the same is true for those states.

As of March 13, the virus had been detected in 46 states and Washington, D.C. With cases now being reported across the country, schools and universities have begun to shut down. Large-scale events like South by Southwest have also been cancelled. The music festival Coachella has been postponed for six months. The CDC is now recommending that people over the age of 60 or who have existing medical conditions limit all non-essential travel, even domestically. Even healthy, young individuals are being urged to practice “social distancing,” where unnecessary contact with others is drastically reduced to slow the rate at which a disease can move through a community.

You can see a full list of states with presumptive and confirmed positives here.

But while all Americans should be taking precautions to avoid catching and spreading COVID-19, most people under the age of 60 and without pre-existing medical conditions do not need to worry they’ll suffer serious symptoms. At a press briefing on February 3, the CDC’s National Center for Immunization and Respiratory Diseases Director Nancy Messonnier said that while she could not comment on the condition of individual patients, the department has seen “a spectrum of illness” among patients in the United States.

“Some cases seem pretty mild, while at least some at points in their illness have been more seriously ill,” she said, adding that some patients had seen “ups and downs” and at least a few had required oxygen of some kind. She emphasized that data out of China continued to suggest those at highest risk of death were the elderly and those with underlying health problems.

The CDC expects many more cases to emerge as the virus can seemingly be spread via coughs and sneezes; reports from China indicate that the vast majority of patients have symptoms minor enough to be mistaken for an innocuous cough or cold.

How deadly is the novel coronavirus?

As of March 13, around 5,000 people had died of COVID-19. More than 1,800 of those deaths have occurred outside China. Fatalities have been reported in Italy, Iran, South Korea, Spain, Germany, France, the US, Japan, Switzerland, the Netherlands, Sweden, the UK, Belgium, Austria, Greece, Hong Kong, Australia, Canada, Egypt, Iraq, Thailand, India, Ireland, San Marino, Lebanon, Poland, Philippines, Taiwan, Indonesia, Algeria, Albania, Argentina, Azerbaijan, Panama, Bulgaria, Morocco, and Guyana.

The US confirmed its first fatality related to COVID-19 on February 29. The King County, Washington, patient was a man in his 50s, according to state health officials, and he suffered from underlying health problems that have not been specified. He has no travel history that can explain his infection with COVID-19. Officials in the same county reported a second death the following day: a man in his 70s, who lived in a nursing home where several patients and staff members are currently ill with COVID-19. Health officials announced the deaths of another three nursing home residents on Monday, along with sixth fatality in nearby Snohomish County. Washington’s death toll has now risen to 31, including some patients only diagnosed with COVID-19 posthumously. California also reported its first death on March 4: an elderly individual in Placer County. Florida and Georgia have also reported fatalities.

In January the WHO told CBS it considered the death rate for the novel coronavirus to be around 2 percent. On March 4 the WHO announced that global cases now put the fatality rate at 3.4 percent. Some experts suspect the true fatality rate of the virus may be lower, with rates inflated due to the fact that so many cases of COVID-19 feature only mild symptoms. It’s likely that many of these mild cases are going undetected.

“It’s good to remember that when H1N1 influenza came out in 2009, estimates of case fatality were 10 percent,” David Fisman, an epidemiologist at the University of Toronto, told Reuters. The actual fatality rate turned out to be well under 1 percent.

For more information on what the COVID-19 death rate actually means, click here.

What are the symptoms of COVID-19?

Symptoms of COVID-19 include cough, fever, and difficulty breathing, but seem to usually be quite minor or even nonexistent in infected individuals. Life-threatening pneumonia is possible for any patient, however, and seniors, individuals with underlying health problems, and people with compromised immune systems are at particularly high risk.

The BBC reported that, according to China’s National Health Commission, around 80 percent of COVID-19 fatalities had occurred in those over the age of 60, and 75 percent of deceased patients had underlying health conditions at the time of their infection.

Here’s everything you need to know about COVID-19 testing.

How is the novel coronavirus transmitted?

The virus can be spread via sneezing and coughing, and perhaps via direct contact when no symptoms are present. For now, it’s unclear whether or not completely asymptomatic patients can infect others with the virus, but the mild nature of symptoms in many patients suggests one could be contagious without feeling particularly unwell.

According to the CDC, person-to-person transmission is most likely to occur via respiratory droplets from coughing and sneezing, which can land in a bystander’s nose or mouth or be inhaled. The virus can survive for some time on surfaces and be transferred when someone touches their face, mouth, or eyes—but practicing the same basic hygiene you would implement to avoid a cold or flu should significantly cut down on your risk of getting sick, even if you’re in close quarters with someone who has COVID-19.

Here is more information on all the ways you can—and can’t—catch COVID-19.

Is there a treatment or a vaccine for the novel coronavirus?

Several pharmaceutical companies and research institutions around the globe are working to find potential treatments or vaccines for COVID-19. A U.S. biotech firm says its vaccine is ready for preliminary testing, but the process of approving it could take as long as a year. It could easily take months to get a formula that works well enough to test on humans, let alone something that can be broadly deployed.

Many claims of cures or preventative treatments are circulating online, but the WHO confirms that there’s no known supplement, food, or medication that can protect people from COVID-19. However, it is advisable to get a flu shot if you have yet to do so: The similar symptoms between the two viruses could lead those with influenza to take up valuable space and time in hospitals, and a compromised immune system could leave you more susceptible to catching COVID-19.

What can people do to avoid catching COVID-19?

The WHO advises travelers who may come into contact with the virus to follow basic precautions, such as avoiding people who are coughing or sneezing and frequently washing hands thoroughly.

Face masks aren’t particularly helpful in preventing infection when healthy people wear them (their main benefit is to keep the virus from spreading via coughs and sneezes), and hoarding them can do more harm than good by limiting the available supply for health practitioners and causing prices to spike.

“This situation is exacerbated by widespread use of personal protective equipment outside patient care,” WHO Director-General Tedros said at a press conference earlier in February.

On February 29 U.S. Surgeon General Jerome Adams tweeted a plea for healthy individuals to stop buying masks for just this reason.

If you have symptoms of COVID-19, your first strategy should be to self-isolate and care for yourself at home, the way you would if you had a cold or the flu. If you start to experience shortness of breath or chest pain, call ahead before going to a doctor’s office or emergency room, as healthcare practitioners are aiming to limit direct contact between potential patients and other individuals.