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Coronavirus Disease 2019 (COVID-19): Overview

Coronavirus disease 2019 (COVID-19) is an illness that infects the lungs. It's caused by a type of coronavirus called SARS-CoV-2. There are many types of coronaviruses. They are a very common cause of colds and bronchitis. They can cause a lung infection called pneumonia. Symptoms can range from mild to severe. Some people have no symptoms. These viruses are also found in some animals.

The virus that causes COVID-19 changes (mutates) all the time. This is what all viruses do. It leads to different versions of a virus. These are called variants. COVID-19 variants may spread more easily from person to person. They may cause milder or more severe symptoms. 

How the virus spreads is not yet fully known. It seems to spread and infect people easily. Some people may not know how they were infected. The virus may spread through droplets of fluid that a person coughs or sneezes into the air. It may be spread if you touch a surface with the virus on it and then touch your eyes, nose, or mouth. Handles, knobs, and objects may have the virus on them.

Woman washing hands at kitchen sink.
To help prevent spreading the infection, wash your hands often, or use an alcohol-based hand sanitizer.

For the latest information from the CDC:

  • Go to the CDC website

  • Call 800-CDC-INFO (800-232-4636)

What are the symptoms of COVID-19?

Some people have no symptoms. Some have mild symptoms. And other people may have severe symptoms. Types of symptoms can vary from person to person. They may appear 2 to 14 days after contact with the virus. They can include:

  • Fever

  • Chills

  • Coughing

  • Trouble breathing or feeling short of breath

  • Sore throat

  • Stuffy or runny nose

  • Headache

  • Body aches

  • Tiredness

  • Nausea, vomiting, diarrhea, or abdominal pain

  • New loss of sense of smell or taste

Check your symptoms with the CDC’s Coronavirus Self-Checker.

What are possible complications of COVID-19?

The virus can cause an infection in both lungs called pneumonia. In some cases, this can lead to death. Experts are still learning more about COVID-19 complications. More may be linked to the virus over time.

Some people are at higher risk for complications. This includes:

  • Older adults

  • People with heart or lung disease

  • People with diabetes or kidney disease

  • People with health conditions that suppress the immune system

  • People who take medicines that suppress the immune system

Rarely, a child may have a severe complication. This is called multisystem inflammatory syndrome in children (MIS-C). MIS-C seems to be like Kawasaki disease. This is a rare illness that causes inflammation of blood vessels and body organs. It's not yet known if MIS-C happens only in children. Experts don’t know if adults are also at risk. It's also not known if it's related to COVID-19. Many children with MIS-C have tested positive for COVID-19. But not all have tested positive. Experts continue to study MIS-C. 

How is COVID-19 diagnosed?

Your healthcare provider will ask:

  • What symptoms you have

  • Where you live

  • If you’ve traveled recently

  • If you’ve had contact with sick people

 You may have 1 of these tests for COVID-19:

  • Viral (molecular) test. You may also hear this called an RT-PCR test. Viral tests are very accurate. A viral test looks for the DNA of the SARS-CoV-2 virus. A viral test can also find COVID-19 variants. There are a few ways to do this. A swab may be wiped inside your nose or throat. Or a long swab may be put into your nose down to the back of your throat. Or a sample of your saliva may be taken. Your test results may be back in about 30 minutes. This depends on the type of test. Some tests must be sent to a lab. These can take several days for the results. Home test kits are now available. Some of these need a prescription. If you use a home kit, follow the instructions in the kit closely. Some kits show results quickly at home. Others must be sent to a lab for the results.

  • Antigen test. This can find proteins from the SARS-CoV-2 virus. A swab may be wiped inside your nose or throat. Or a long swab may be put into your nose down to the back of your throat. Some results are back within 1 hour. This depends on the type of test. Positive results are very accurate. But false positive results can happen. This is more common in places where not many people have the virus. Antigen tests are more likely to miss a COVID-19 infection than a viral (molecular) test. If your antigen test is negative but you have symptoms of COVID-19, you may need to have a viral test.

If your provider thinks or confirms that you have COVID-19, you may have other tests. These tests may include:

  • Antibody blood test. This type of test can show if you were infected with the virus in the past. It shows antibodies in the blood that give some immunity. The accuracy and availability of these tests vary. An antibody test may not be able to show if you have an infection right now. This is because it can take up to a few weeks for your body to make antibodies.

  • Sputum culture. If you have a wet cough, you may be asked to cough up a small sample of mucus (sputum) from your lungs. This is tested for the virus. It may be tested for pneumonia.

  • Imaging tests. You may have a chest X-ray or CT scan.

Can you get COVID-19 again?

At this time, it's not clear if people can get COVID-19 more than once. The CDC notes that if a person has recovered from COVID-19 and is tested again within 3 months, they may still have low levels of the virus in their body. This means they test positive for COVID-19, but are not spreading it. Experts just don’t yet know how long immunity lasts after you have the virus. They don’t know if you can get COVID-19 again.

Vaccines for COVID-19

The FDA has approved several vaccines to help prevent COVID-19. Getting a vaccine is important. It can help to prevent the spread of COVID-19 and its variants. It can help reduce the severity of COVID-19 if you get it. This can stop you from getting seriously ill. It can keep you from needing to go to the hospital. One vaccine has been approved for people as young as 12. Pregnant or breastfeeding people can be vaccinated. Ask your healthcare provider which vaccine may be best for you.

The vaccines are given as a shot (injection). This is most often done in a muscle in the upper arm. There are 1-dose and 2-dose vaccines. For the 2-dose vaccine, the second dose is given several weeks after the first.

How is COVID-19 treated?

The most proven treatments right now are those to help your body while it fights the virus. This is known as supportive care. It includes:

  • Getting rest. This helps your body fight the illness.

  • Drinking fluids. Try to drink 6 to 8 glasses of fluids every day. Ask your provider which drinks are best for you. Don't have drinks with caffeine or alcohol.

  • Taking over-the-counter (OTC) medicine. These are used to help ease pain and reduce fever. Ask your provider which OTC medicine is safe for you to use.

For severe illness, you may need to stay in the hospital. Your care may include:

  • IV (intravenous) fluids. These are given through a vein. This helps to replace fluids in your body.

  • Oxygen. You may be given supplemental oxygen. Or you may be put on a breathing machine (ventilator). This is done so you get enough oxygen in your body.

  • Prone positioning. Your healthcare team may regularly turn you on your stomach. This is called prone positioning. It helps increase the amount of oxygen you get to your lungs. Follow their instructions on position changes while you're in the hospital. Also follow their advice on the best positions to help your breathing once you go home.

  • Remdesivir. This is an antiviral medicine. The FDA has approved it for use on COVID-19. It works by stopping the spread of the SARS-CoV-2 virus in the body. It's approved only for people who are in the hospital. It's for people 12 years and older who weigh at least 88 pounds (40 kgs). In some cases, it may also be used for people younger than 12 years or who weigh less than 88 pounds (40 kgs).

Experts are researching other types of treatment. These are still being tested. They are not widely used. These include:

  • COVID-19 convalescent plasma. Plasma is the liquid part of blood. People who had COVID-19 may be asked to donate plasma. This is called COVID-19 convalescent plasma donation. The plasma may have antibodies that can help fight COVID-19 in people who are very ill with it. Experts don't know how well the plasma will work. They continue to research it. The FDA has approved it for emergency use in some people with severe COVID-19. Ask your provider if you qualify to donate.

  • Monoclonal antibody therapy. The FDA approved this for emergency use in some people. They must have a positive COVID-19 viral test and have mild to moderate symptoms. They can’t be in the hospital. It's approved for people 12 years and older who weigh at least 88 pounds (40 kgs) and are at high risk for severe COVID-19 and a hospital stay. This includes people who are 65 years and older and people with some chronic conditions. This therapy is not approved for people who are in the hospital with COVID-19 or need oxygen. Your healthcare team will tell you if you qualify.

Are you at risk for COVID-19?

You are at risk for COVID-19 if any of these apply to you:

  • You live in an area with cases of COVID-19

  • You traveled to an area with cases of COVID-19

  • You had close contact with someone who had COVID-19

Close contact means being within 6 feet. This contact happens for 15 minutes or more. It may be short times of contact that add up to at least 15 minutes over a 24-hour period.

Keep in mind that COVID-19 may be spread by people who do not show symptoms.

Last updated: 7/1/2021

Online Medical Reviewer: Arnold Lentnek MD FACP
Online Medical Reviewer: L Renee Watson MSN RN
Date Last Reviewed: 1/1/2020
© 2000-2021 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.