A coronavirus is a kind of common virus that causes an infection in your nose, sinuses, or upper throat. Most coronaviruses aren't dangerous.

In early 2020, after a December 2019 outbreak in China, the World Health Organization identified SARS-CoV-2 as a new type of coronavirus. The outbreak quickly spread around the world.

COVID-19 is a disease caused by SARS-CoV-2 that can trigger what doctors call a respiratory tract infection. It can affect your upper respiratory tract (sinuses, nose, and throat) or lower respiratory tract (windpipe and lungs).

It spreads the same way other coronaviruses do, mainly through person-to-person contact. Infections range from mild to deadly.

SARS-CoV-2 is one of seven types of coronavirus, including the ones that cause severe diseases like Middle East respiratory syndrome (MERS) and sudden acute respiratory syndrome (SARS). The other coronaviruses cause most of the colds that affect us during the year but aren’t a serious threat for otherwise healthy people.

How does the coronavirus spread?

As of now, researchers know that the coronavirus is spread through droplets and virus particles released into the air when an infected person breathes, talks, laughs, sings, coughs or sneezes. Larger droplets may fall to the ground in a few seconds, but tiny infectious particles can linger in the air and accumulate in indoor places, especially where many people are gathered and there is poor ventilation. This is why mask-wearing, hand hygiene and physical distancing are essential to preventing COVID-19.

How did the coronavirus start?

The first case of COVID-19 was reported Dec. 1, 2019, and the cause was a then-new coronavirus later named SARS-CoV-2. SARS-CoV-2 may have originated in an animal and changed (mutated) so it could cause illness in humans. In the past, several infectious disease outbreaks have been traced to viruses originating in birds, pigs, bats and other animals that mutated to become dangerous to humans. Research continues, and more study may reveal how and why the coronavirus evolved to cause pandemic disease.

What is the incubation period for COVID-19?

Symptoms show up in people within two to 14 days of exposure to the virus. A person infected with the coronavirus is contagious to others for up to two days before symptoms appear, and they remain contagious to others for 10 to 20 days, depending upon their immune system and the severity of their illness. 

What are symptoms of coronavirus?

COVID-19 symptoms include:

• Cough
• Fever or chills
• Shortness of breath or difficulty breathing
• Muscle or body aches
• Sore throat
• New loss of taste or smell
• Diarrhea
• Headache
• New fatigue
• Nausea or vomiting
• Congestion or runny nose

Some people infected with the coronavirus have mild COVID-19 illness, and others have no symptoms at all. In some cases, however, COVID-19 can lead to respiratory failure, lasting lung and heart muscle damage, nervous system problems, kidney failure or death.

If you have a fever or any of the symptoms listed above, call your doctor or a health care provider and explain your symptoms over the phone before going to the doctor’s office, urgent care facility or emergency room. Here are suggestions if you feel sick and are concerned you might have COVID-19.

Transmission

Coronavirus infections are contagious, and some of these viruses, including the one that causes COVID-19, spread easily between people. Researchers believe that the viruses transmit via fluids from the respiratory system.

Transmission may happen when a person:

• coughs or sneezes without covering their mouth, dispersing droplets containing the virus into the air
• has physical contact with someone who has the infection
• touches a surface that contains the virus, then touches their nose, eyes, or mouth

Ways of preventing transmission include:

• wearing a face covering in public
• avoiding touching the face, especially the mouth and nose
• always coughing or sneezing into a tissue, then disposing of it and washing the hands right away
• regularly and thoroughly washing the hands

During the ongoing COVID-19 pandemic, people should also do the following, even if they are well: Stay home whenever possible.

• Avoid contact with others.
• Wear a face covering in public.
• Stay at least 6 feet away from others in public.

Anyone with symptoms of COVID-19 should isolate at home and rest until the symptoms have passed. Contact a doctor for more information, and let them know if the symptoms seem to be worsening.

Vaccines can help prevent infection with SARS-CoV-2.