Here's what to look for and how to protect yourself and others.

By Leah Groth
Updated May 14, 2020

In December 2019, an outbreak of an unknown coronavirus began circulating in Wuhan, China—and now cases of the novel coronavirus, known as COVID-19, have been diagnosed in every state. Johns Hopkins University's global tracking system counts more than 1.4 million US cases. America has more confirmed cases than any other country and, as of May 14, at least 85,000 people have died from the illness.

Globally, more than 4.4 million people who have been infected, while the death toll exceeds 300,000, says Johns Hopkins. And according to the journal Science, there may be as many as five to 10 undetected cases of coronavirus for every confirmed case, reports the New York Times.

Expressing deep concern over the "rapid escalation and global spread of infection," World Health Organization (WHO) Director-General Tedros Adhanom Ghebreyesus on March 11 recognized the threat as a pandemic caused by a coronavirus.

But what exactly is a coronavirus—this one in particular—and how worried should you be about it?

Where did the novel coronavirus—aka COVID-19—come from?

This strain of novel (aka, new) coronavirus has never before been identified in humans. The WHO explains that they were first informed of cases of pneumonia of unknown etiology (unknown cause) detected in Wuhan City, Hubei Province of China on December 31, 2019. 

Since Chinese officials confirmed the new coronavirus—SARS-CoV-2—on January 7,  cases of COVID-19 have spread globally. 

According to the CDC, SARS-Cov-2 is a type of betacoronavirus, which likely originated in bats. Early on during the outbreak, the CDC noted that patients at the epicenter of the outbreak in Wuhan, China, had a connection to a large seafood and live animal market, suggesting animal-to-human transmission of the virus. (The rumor of "bat soup" being the origin of the virus, however, is false). Later on, the virus continued to spread between those who hadn't had a connection to the animal market, suggesting human-to-human transmission.

What are coronaviruses in general?

So, coronaviruses are a large group of viruses, a category that includes the common cold as well as more severe respiratory conditions. As the CDC explains, some coronaviruses infect certain types of animals, while others cause illness in people. It is possible for an animal coronavirus to jump to humans and then spread from person to person, but that is rare, says the CDC.

In all, there are seven different types of human coronaviruses that can infect humans (most of which are known simply by a combination of letters and numbers: 229E, NL63, OC43, and HKU1). Those common coronaviruses are often characterized by respiratory symptoms like fever, cough, shortness of breath, and breathing difficulties.

SARS-CoV-2, the virus that causes COVID-19, is believed to be one of those rare instances of an animal virus spreading to humans, although the exact cause isn't yet known, CDC points out. SARS-CoV, the coronavirus that causes SARS (Severe Acute Respiratory Syndrome Coronavirus), and MERS-CoV, which causes MERS (Middle East Respiratory Syndrome Coronavirus) are two others that originated in animals.

What are the symptoms of the coronavirus?

For coronaviruses in general, common signs of infection include respiratory symptoms like fever, cough, shortness of breath and breathing difficulties. As for COVID-19 in particular, the list of potential symptoms has expanded as scientists have learned more about how the virus behaves.

According to the WHO, the most common COVID-19 symptoms are: 

  • Dry cough
  • Fever
  • Tiredness

Some people may also have:

  • Aches and pains
  • Nasal congestion
  • Headache
  • Conjunctivitis
  • Sore throat
  • Diarrhea
  • Loss of taste or smell
  • Skin rash
  • Discoloration of fingers or toes

The CDC also has revised its list of COVID-19 symptoms. It now says people may have COVID-19 if they have:

  • Cough
  • Shortness of breath or difficulty breathing
  • Fever
  • Chills
  • Muscle pain
  • Sore throat
  • New loss of taste or smell

CDC says that list is not exhaustive. Other possible but less common symptoms include gastrointestinal troubles, like nausea, vomiting, or diarrhea.

Symptoms can show up within two to 14 days of exposure to the virus, and they can range from very mild to severe. The CDC urges people who have trouble breathing, pain or pressure in their chest, new confusion or inability to arouse, bluish lips or face, or any other emergency warning signs to seek medical attention immediately.

Also important to note: There's no approved treatment or vaccine for COVID-19—another reason why it's of the utmost importance to contain the virus ASAP. While researchers are working on treatments and prevention methods, it's unlikely that anything will come about soon enough to help fight against this current strain of coronavirus, though they may be helpful against future viruses.

How is the coronavirus spread?

Since COVID-19 is new, scientists are still learning about how the virus is spread. The primary mode of transmission is thought to be from person-to-person via respiratory droplets that are produced when an infected person coughs or sneezes and a nearby person either gets those droplets in their eyes, nose, or mouth, or perhaps even inhales particles sprayed into the air, says Penn Medicine.

However, public officials now know that even asymptomatic people can harbor the virus and transmit it to others.

Another way the virus spreads is through communal contact with contaminated surfaces, says the CDC. That can happen when an infected person sneezes into their hand and touches a surface, which then becomes contaminated. However, it's not believed to be the main source of transmission. And while the risk of transmission from the feces of someone with COVID-19 is unknown, it thought to be low based on data from prior SARS and MERS outbreaks, adds CDC.

It has become increasingly clear that the coronavirus can easily pass from person to person in some geographic areas, even though the source of infection isn't known—a phenomenon known as community spread. In other words, you can acquire the infection even if you don't think you've been exposed to someone with the illness. Most states have adopted stay-at-home or shelter-in-place measures to limit the transmission of the virus, per the New York Times.

How severe is the coronavirus—and what's the mortality rate?

Early data from China suggested that COVID-19 is generally a mild illness, especially for children and healthy adults. It can, however, cause serious illness and death—even in younger, healthier people, but especially among adults 65 and older and those with chronic conditions.

A report examining outcomes among Americans with COVID-19 confirms that older adults are among the most vulnerable. Death rates range from 10-27% among adults 85 and older, according to Morbidity and Mortality Weekly Report. For people 65 to 85, the death rate ranges from 3-11%; for those 55 to 64, it's 1-3%. It's less than 1% for younger Americans—and there were no deaths among youth under 19.

That doesn't mean children or young adults are out of the woods. Among people known to have been hospitalized for COVID-19, 20% were 20 to 44, according to MMWR. And while most pediatric cases appear to be mild, public health officials in a number of states are reporting cases of a serious illness, now called pediatric multi-system inflammatory disorder, which appears to be associated with COVID-19.

How can you protect yourself (and others) against the coronavirus?

You might be tempted to run out and stock up on face masks (if you can even find them). Initially the CDC did not recommend wearing a mask but recently revised its advice based on evidence that asymptomatic and pre-symptomatic people can spread the disease by speaking, coughing, or sneezing. It now encourages people to wear a cloth face covering in public places where it's difficult to maintain social distance, like the grocery store, especially in parts of the country where there is widespread community transmission. However, CDC doesn't want people to acquire medical masks or respirators, which are in short supply. Save those for medical workers and first responders.

The idea behind wearing a face mask in public is not to protect yourself. It's meant to help slow the spread of the virus, hopefully preventing  people who don't yet know they're infected from passing it along to others.

Guidelines jointly issued by the CDC and White House call on all Americans to limit person-to-person transmission. That means hunkering down at home if you are older or have a serious underlying health condition, if you are ill, or if have been exposed to someone who is ill. Everyone—the young and healthy included—is urged to avoid social gatherings of more than 10 people and avoid discretionary travel.

As for preventive measures, the CDC continues to say your best bet for dodging the coronavirus is to clean your hands often using soap or hand sanitizer containing at least 60% alcohol; avoid close contact with people who are sick; maintain a buffer zone of at least six feet between yourself and other people; clean commonly touched surfaces and objects; cover coughs and sneezes; and keep your hands away from your face as much as possible.

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, and their local public health department as resources.

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