Coronavirus disease 2019 (COVID-19)


Coronavirus disease 2019 (COVID-19) is a respiratory illness that causes fever, coughing, and shortness of breath. Some people with COVID-19 have died. Some people have none or only mild symptoms.

Alternative Names

Coronavirus-2019; Coronavirus-Novel 2019; 2019 Novel Coronavirus; 2019-nCoV; SARS-CoV-2


COVID-19 is caused by the SARS-CoV-2 virus (severe acute respiratory syndrome coronavirus 2). Coronaviruses are a family of viruses that can affect people and animals. They can cause mild to moderate respiratory illnesses, such as the common cold. Some coronaviruses can cause severe illness that can lead to pneumonia and even death.

COVID-19 was first reported in Wuhan City, Hubei Province, China in early December, 2019. Since then, it quickly spread within China and to other locations in Africa, Asia, Australia, Europe, and North and South America, including the United States.

SARS-CoV-2 is a betacoronavirus, like the MERS and SARS coronaviruses, which both originated in bats. It is thought that the virus spread from animals to humans. Now the virus is mainly spreading from person-to-person.

COVID-19 is thought to spread to people within close contact (about 6 feet or 1.8 meters). When someone with the illness coughs or sneezes, infected droplets spray into the air. You can catch the illness if you breathe in or touch these particles.

COVID-19 can cause mild to serious illness and even death. It is also spreading from person to person quickly. The United States Centers for Disease Control and Prevention (CDC) and World Health Organization consider COVID-19 a serious public health threat globally and in the United States. However, most people in the United States are not at immediate risk. The situation is evolving quickly, so it's important to follow current local guidance on how to protect yourself and others from getting and spreading COVID-19.


COVID-19 symptoms have ranged from mild to severe, and some people have died from the illness. Older people and people with existing health conditions such as heart disease, diabetes, or lung disease have a higher risk of developing severe illness.

The main symptoms are:

  • Fever
  • Cough
  • Shortness of breath

Symptoms may appear within 2 to 14 days. The CDC recommends that if you have developed a fever, cough, or difficulty breathing, and:

You have recently traveled from an area where COVID-19 is spreading,


You have had close contact with someone who is known to have COVID-19,

you should:

  • Seek medical care right away. Before you go to a doctor's office or emergency department (ED), call ahead and tell them about your recent travel, other potential exposures to the virus, and your symptoms. If available, wear a face mask when you visit the office or ED.
  • Avoid contact with other people.
  • As much as possible, stay in a specific room and away from others in your home. Use a separate bathroom if you can. Do not leave your home except to get medical care.
  • Use a face mask when you are with people in the same room and when you see your health care provider. If you can't wear a mask, for example, due to breathing problems, people in your home should wear a mask if they need to be in the same room with you.
  • Avoid contact with pets or other animals. (Some coronaviruses can spread to animals. It is not clear if SARS-CoV-2 can spread from people to animals.)
  • Do not travel while sick. Do not use public transportation or taxis.
  • Cover your mouth and nose with a tissue or your sleeve (not your hands) when coughing or sneezing. Throw away the tissue after use.
  • Wash your hands often with soap and water for at least 20 seconds. Do this after coughing, sneezing, or blowing your nose. Use an alcohol-based hand sanitizer (at least 60% alcohol) if soap and water are not available.
  • Avoid touching your face, eyes, nose, and mouth with unwashed hands.
  • Do not share personal items such as cups, eating utensils, towels, or bedding. Wash anything you have used in soap and water.
  • Clean all "high-touch" areas in the home, such as doorknobs, bathroom and kitchen fixtures, toilets, phones, tablets, and counters and other surfaces. Use a household cleaning spray and follow instructions for use.
  • You should remain at home and avoid contact with people until your provider tells you it is safe to resume your regular activities.

Exams and Tests

Samples of blood, sputum, and swabs from the back of the nose and throat may be taken. In some cases, samples of fluid from the lungs may be collected by bronchoscopy. Urine and stool samples also may be collected for further testing. If a person is thought to have COVID-19, these samples will be tested for SARS-CoV-2.


There is no specific treatment at this time, although some people are being given experimental medicines. Supportive care is given to help relieve symptoms. People with severe illness will be treated in the hospital.

Possible Complications

Complications can include:

  • Respiratory failure
  • Death

When to Contact a Medical Professional

If you have traveled to an area where COVID-19 is spreading or have been in contact with someone with COVID-19 within the last two weeks and develop symptoms, contact your provider right away.


There is no vaccine for COVID-19. The best way to avoid infection is to avoid people who have the virus. For that reason, the CDC is recommending that people do not travel to areas where the virus is spreading. For up-to-date travel information, you can check the CDC travel health notices page.

If you must travel, talk with your provider before you travel. While there:

  • Avoid contact with sick people.
  • Avoid animals (alive or dead), animal markets, and products that come from animals (such as uncooked meat).
  • Wash your hands often. Use an alcohol-based hand sanitizer if soap and water are not available.

Taking these steps can prevent the spread of respiratory viruses:

  • Wash your hands for at least 20 seconds with soap and water, or clean them with an alcohol-based instant hand sanitizer.
  • Don't touch your eyes, nose, and mouth with unwashed hands.
  • Cover your mouth and nose with a tissue when you sneeze or cough. Droplets that are released when a person sneezes or coughs are infectious. Throw the tissue away after use.
  • DO NOT share food, drink, or utensils.
  • Clean commonly-touched surfaces with a disinfectant.

For the most up-to-date news and information about COVID-19, you can visit the following websites:

Centers for Disease Control and Prevention website. Coronavirus Disease 2019 (COVID-19).

World Health Organization website. Coronavirus Disease 2019 (COVID-19) outbreak.


Centers for Disease Control and Prevention website. Coronavirus disease 2019 (COVID-2019) Updated March 6, 2020. Accessed March 7, 2020.

Centers for Disease Control and Prevention website. Frequently asked questions and answers. Updated March 3, 2020. Accessed March 7, 2020.

Centers for Disease Control and Prevention website. Information for healthcare professionals. Updated March 3, 2020. Accessed March 7, 2020.

Centers for Disease Control and Prevention website. Coronavirus disease 2019 information for travelers. Updated March 4, 2020. Accessed March 7, 2020.

Review Date: 02/03/2020

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright ©2019 A.D.A.M., Inc., as modified by University of California San Francisco. Any duplication or distribution of the information contained herein is strictly prohibited.

Information developed by A.D.A.M., Inc. regarding tests and test results may not directly correspond with information provided by UCSF Health. Please discuss with your doctor any questions or concerns you may have.