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What Is a Coronavirus?

The CDC recommends that all people wear cloth face masks in public places where it’s difficult to maintain a 6-foot distance from others. This will help slow the spread of the virus from people without symptoms or people who do not know they have contracted the virus. Cloth face masks should be worn while continuing to practice social distancing. Instructions for making masks at home can be found here. Note: It’s critical to reserve surgical masks and N95 respirators for healthcare workers.

The term “coronavirus” refers to a large group of viruses known to affect birds and mammals, including humans. COVID-19, which first appeared in China in December 2019, is a type of coronavirus.

Coronaviruses are named for the spiky projections on their surface. These resemble the points on a crown. Corona means “crown” in Latin.

There are hundreds of coronaviruses, but only seven are known to affect people. Four human coronaviruses only cause mild cold- or flu-like symptoms. Three other coronaviruses pose more serious risks.

Keep reading to learn more about the types of coronaviruses, including COVID-19.

Types of human coronaviruses All seven types of human coronaviruses cause upper respiratory infections. Symptoms resemble those of the common cold or flu and may include:

  • nasal congestion

  • sore throat

  • cough

  • headaches

  • fever

According to the Centers for Disease Control and Prevention (CDC), coronaviruses occasionally cause complications in the lower respiratory tract, such as pneumonia. These complications are more common among:

  • infants

  • older adults

  • people with other illnesses or weakened immune systems

The seven coronaviruses that affect humans can be categorized into two groups. Common human coronaviruses There are four common human coronaviruses:

  • 229E

  • NL63

  • OC43

  • HKU1

Common human coronaviruses usually cause mild to moderate symptoms. Most people around the world will develop at least one of these viral infections over their lifetime. Those who contract these viruses are able to recover on their own most of the time.

Other human coronaviruses

Three additional coronaviruses originated as animal infections. Over time, these viruses evolved and were eventually transmitted to humans.

These coronaviruses pose more serious risks to human health. They’re described below.


SARS-CoV causes Severe Acute Respiratory Syndrome (SARS). According to the World Health Organization (WHO), the first human cases appeared in southern China in November 2002.

SARS-CoV may have originated in bats and were transmitted to other animals before infecting humans.

During the 2002-2003 epidemic, more than 8,000 people in 26 countries around the world contracted SARS. There were reported deaths.

The outbreak was contained in mid-2003 with the implementation of infection control practices such as isolation and quarantine. Since then, a handful of cases have occurred due to laboratory accidents.

There are currently no reported cases of SARS transmission in the world. However, if the virus re-emerges, it could pose a significant threat to the public.


MERS-CoV causes Middle East Respiratory Syndrome (MERS). According to WHO, it emerged in September 2012 in Saudi Arabia, although initial cases were later traced back to Jordan.

Humans contract MERS-CoV through contact with camels that have contracted the infection. The virus is also transmitted by coming into very close contact with a person who has the infection.

Since 2012, 27 countries have reported more than 2,400 MERS cases. To date, the majority of cases have occurred in Saudi Arabia.

In 2015, an outbreak in South Korea led to 186 cases and 36 deaths. According to the CDC, this outbreak originated with a traveler returning from the Middle East.

According to the European Center for Disease Prevention and Control (ECDPC), there were more than 200 cases of MERS-CoV reported in 2019.

Health authorities around the world continue to monitor MERS cases.


SARS-CoV-2 causes COVID-19. This new coronavirus appeared in Wuhan, China, in late December 2019 after health officials noticed an increase in pneumonia cases with no known cause.

These cases have since been linked to a market selling seafood and poultry. Though the virus likely evolved from an animal source, its exact source is unknown.

Within a few months, SARS-CoV-2 has spread to hundreds of countries around the world after being transmitted through person-to-person contact.

What type of coronavirus originated in China in 2019?