9 questions about the Covid-19 coronavirus pandemic, answered


The coronavirus outbreak, which began in China, keeps evolving at a dizzying speed. With the global case toll rising steeply, face masks flying off store shelves, borders around the world closing, and meetingscruise itineraries, and the global economy upended by the virus, it’s no wonder questions and fears are swirling about Covid-19, as the disease is known.

On March 11, the WHO declared the outbreak a pandemic, a new disease that has spread around the world. Many countries have seen reported cases of the virus rise within their borders — and that includes the US.

“We will see more cases, and things will get worse,” Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told members of the House Oversight Committee on March 11. “How much worse … will depend on our ability to do two things: to contain the influx in people who are infected coming from the outside and the ability to contain and mitigate within our own country.”

Spread of the virus and the slow rollout of testing mean reported case numbers are changing quickly. Meanwhile, outbreaks have been surging in South Korea, Italy, and Iran. With the new virus continuing its tour around the world, here are answers to your most burning questions.SARS is thought to have evolved from infecting bats to civet cats to humans in China; MERS evolved from bats to camels to humans in the Middle East. No one knows precisely where Covid-19 came from, though a leading hypothesis is that bats were once again the original source: They spread the virus to another animal species, possibly a pangolin, where it jumped to humans.

2) What are the symptoms and death rate?

Two of the seven coronaviruses that infect humans, SARS and MERS, can cause severe pneumonia and even death in 10 and more than 30 percent of cases, respectively. But others lead to milder symptoms, like a common cold. The most common symptoms of Covid-19 are fever and dry cough.

No one knows the precise incubation period for the virus, but symptoms can show up anywhere from one day to two weeks after exposure, according to a WHO report on China’s response.

At the moment, we know Covid-19 can cause pneumonia and that it too can kill — but while it seems to be less deadly than SARS and MERS, it’s not yet clear by precisely how much.

Some of the best evidence on the question comes from a February 16 China Center for Disease Control report looking at the outcomes of the first 72,314 patients with confirmed or suspected Covid-19 in mainland China. It’s the largest such analysis to date, and it found an overall case fatality rate of 2.3 percent — lower than both SARS and MERS. (The case fatality rate, or CFR, is the proportion of deaths a disease causes within a group of people who have the disease.)

At the same time, there’s also evidence of asymptomatic cases. And it’s possible that as we discover more of these cases, Covid-19 will look less deadly. That’s because infectious diseases typically look more severe when they’re first discovered since the people showing up in hospitals tend to be the sickest. Disease modelers who account for this under-counting of cases currently estimate an overall case fatality rate of just over 1 percent.

As for symptoms: Fever, dry cough, and fatigue are more common, while thick mucus from coughs, shortness of breath, sore throat, and headache are less common, according to China’s data.

But the picture might change as data on symptoms emerge from other countries. For example, a yet-to-be published German paper looked at some of the country’s earliest confirmed Covid-19 patients. Researchers found symptoms in this small sample often resembled a cold. So only two of the nine patients had a fever, and seven had a cough, but just as common were symptoms like stuffy nose, runny nose, and sneezing.

3) What should I do if I think I have Covid-19?

If you’re in a high-risk group — over the age of 60 with an underlying health condition — seek medical treatment immediately, and let your hospital or health care provider know you suspect Covid-19 before showing up.

Otherwise, stay at home and call a health professional, Vox’s Umair Irfan explained: “They will work with your local health department and figure out whether you need to get tested or get treatment. Doctors and health officials advise not to go to the emergency room if your symptoms do not appear to be life-threatening.” There’s a good chance you’ll recover with nothing more than rest and fluids. But you will need to self-isolate while sick to avoid spreading the disease to others, including any people in your home. Here’s how to do it.

And if you are healthy, here are some ways you can help vulnerable people in your community.

4) How do coronaviruses spread?

We don’t yet know exactly how SARS-CoV-2 — the virus that causes the Covid-19 disease — spreads, but we do have a lot of data on how MERS, SARS, and other respiratory viruses move from person to person. And that’s mainly through exposure to droplets from coughing or sneezing.