What Is Coronavirus?

There are many different strains of the coronavirus. Most are not deadly and only cause illnesses like the common cold. Stocktrek Images/Getty Images/Stocktrek Images

This article was first published on Jan. 27, 2020 and last updated on July 10, 2020.

Human coronaviruses (CoV) are a large family of viruses that can cause a variety of illnesses ranging from the common cold to severe diseases like Middle East respiratory syndrome (MERS-CoV) and Severe Acute respiratory syndrome (SARS-CoV). The World Health Organization says Novel Coronavirus (SARS-CoV-2) is a new strain that had not been previously identified in humans until late 2019.



Human coronavirus was first discovered in 1965 and accounts for many cases of the common cold. The virus gets its name from its crown-like shape. Coronaviruses are zoonotic, which means they're transmitted between animals and people. SARS-CoV was transmitted from civet cats to humans and researchers suspect MERS-CoV is transmitted from dromedary camels to humans.

What Is Coronavirus?

Coronaviruses affect all age groups and most are not dangerous. They often only cause mild symptoms like a stuffy nose, cough and sore throat that can be treated with rest and over-the-counter medications. Most coronaviruses spread like any other cold viruses spread, including:

  • through the air by coughing and sneezing
  • close personal contact, such as touching or shaking hands with someone who's sick
  • touching an object with the virus on it, then touching your mouth, nose or eyes

The U.S. Centers for Disease Control (CDC) says people in the United States who get a coronavirus will usually get infected in the fall and winter, though it can happen any time of the year. And most people will get infected with one or more of the common human coronaviruses (229E, NL63, OC43 and HKU1) during their lifetime.

Signs of Infection

  • headache
  • runny nose
  • fever
  • cough
  • shortness of breath
  • sore throat

Severe cases can lead to pneumonia, acute respiratory syndrome, kidney failure and even death.

Wearing a mask properly can help reduce your risk of transmitting the coronavirus.

Novel Coronavirus (SARS-CoV-2)

While four strains of coronaviruses (229E, NL63, OC43 and HKU1) are typically not severe, three others have proven deadly. An outbreak of respiratory illness caused by a new coronavirus (named SARS-CoV-2) was first reported in Wuhan City, Hubei Province, China, in early January 2020. Chinese health officials noted thousands of cases of COVID-19, the disease caused by novel coronavirus, in China, and infections were reported in several international locations, including the U.S. Like other coronaviruses, the symptoms of novel coronavirus include fever, difficulty breathing and pneumonia, and the virus spreads via person-to-person contact.

At the time of this last update, at least 551,046 people have died and more than 12 million people have been infected with COVID-19 worldwide, according to the World Health Organization. Europe is home to more than 2.8 million of the cases; the United States surpassed all of Europe with more than 3 million confirmed cases and 131,884 deaths; Brazil now has more than 1.7 million cases. Brazilian President Jair Bolsonaro tested positive for Covid-19.

The Chinese government took unprecedented steps to curb the virus by placing almost 60 million people on lockdown, and banning travel to and from 15 cities in the Chinese province of Hubei. Italy's Prime Minister Giuseppe Conte also put the entire country, which includes 60 million residents, on lockdown on Tuesday, March 10, 2020, to contain the spread of the virus. The lockdown has now ended.

The United States also implemented travel restrictions that went into effect Feb. 3, 2020. The restrictions required any U.S. citizen returning to the states from China to a mandatory 14 day quarantine, Health and Human Services Secretary Alex Azar said in a press briefing. The U.S. also announced enhanced screening and quarantine measures for Americans returning from Italy and South Korea.

New York Gov. Andrew Cuomo also called out the National Guard on Tuesday, March 10, to help create a 1-mile containment area in New Rochelle, New York, to help stop what was being called a "cluster" of COVID-19 cases. New York City also was on total lockdown and all residents were told to shelter in place. Other major cities in the U.S. also had similar orders, though all ended around Memorial Day weekend.

Some U.S. states and cities, have however, implemented mandates for citizens to wear masks in public. But those mandates have come with serious backlash, even from members of the Trump administration.

While it's been reported the virus might have originated in a food market in Wuhan, the World Health Organization says not enough is known about the epidemiology of this strain of coronavirus to fully understand its features, how it's transmitted and its origins.

The new coronavirus' incubation period is still unknown. However, health officials at the WHO assume it is about 14 days; they are not aware if people are contagious during the incubation period, or how long it can survive on surfaces.

People should can take steps to protect themselves from COVID-19. Here's how:

  • Wear a facemask in public.
  • Avoid contact with sick people.
  • Continue to self quarantine and avoid crowds.
  • Cough and sneeze into a tissue and immediately throw used tissues into a lined trash can.
  • Wash hands often with soap and water for at least 20 seconds.
  • Avoid animals (alive or dead), animal markets and products that come from animals (such as uncooked meat).
  • Use an alcohol-based hand sanitizer if soap and water are not available.
  • Don't share household items like cups, forks, towels and bedding with someone who has the virus.


The other two deadly coronaviruses are SARS and MERS. Severe acute respiratory syndrome (SARS) is a type of coronavirus that was first reported in Asia in February 2003. Detailed investigations found that SARS-CoV was transmitted from civet cats to humans. Due to its contagious nature, SARS became a world epidemic, spreading to 32 countries and infecting 8,459 people. Many of the people who contracted SARS also developed pneumonia, and almost 800 people died as a result of SARS.

SARS generally starts with a high fever (higher than 100.4 degrees Fahrenheit [38 degrees Celsius]), and leads to headache and body aches. Other symptoms include diarrhea and mild respiratory issues. After about a week, most people develop a cough and eventually pneumonia.

Like other coronaviruses, SARS spreads through person-to-person contact. But the CDC says the SARS virus might spread through the air or in other ways that are still not known. The good news is since 2004 there has not been any recorded case of SARS.


Middle East respiratory syndrome (MERS) is a type of coronavirus that was first reported in Saudi Arabia in 2012. It has since spread to several other countries, including the United States. Most people infected with MERS-CoV developed severe respiratory illness, including fever, cough and shortness of breath. The World Health Organization has documented 2,494 cases of MERS since 2012 and 858 deaths.

The symptoms of MERS are similar to other coronaviruses and include:

  • fever
  • cough
  • shortness of breath
  • pneumonia
  • diarrhea

Research has suggested that MERS is spread via person-to-person contact; however, some evidence has shown that dromedary camels also are a major host for MERS-CoV and source of MERS infection in humans. The WHO is still not clear on how the virus jumped from animals to humans, but strains of MERS that are identical to human strains have been isolated from camels in several countries, including Egypt, Oman, Qatar and Saudi Arabia.

There currently is no vaccine for MERS, but scientists are working on creating one. In the meantime, the best ways to protect yourself from MERS are to:

  • Wash your hands often with soap and water.
  • Use alcohol-based hand sanitizer if soap and water are not available.
  • Cover your nose and mouth with a tissue when you cough or sneeze.
  • Avoid touching your eyes, nose and mouth with unwashed hands.
  • Avoid personal contact, such as kissing, or sharing cups or eating utensils, with sick people.
  • Disinfect frequently touched surfaces and objects, such as doorknobs.

Last editorial update on Jul 10, 2020 03:43:39 pm.