Coronavirus disease 2019 (COVID-19) is a respiratory illness. It's caused by a new (novel) coronavirus. There are many types of coronavirus. Coronaviruses are a very common cause of colds and bronchitis. They may sometimes cause lung infection (pneumonia). Symptoms can range from mild to severe. Some people have no symptoms. These viruses are also found in some animals.

All 50 states in the U.S. have reported cases of COVID-19. Many areas report "community spread" of COVID-19. This means the source of the illness is not known. Like other viruses, the virus that causes COVID-19 changes (mutates) all the time. This leads to variants. Many variants of the COVID-19 virus have been found across the world, including in the U.S. COVID-19 variants may spread more easily from person to person. They may cause milder or more severe symptoms. COVID-19 is a rapidly-emerging infectious disease. This means that scientists are actively researching it. There are information updates regularly.

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Public health officials are working to find the source. How the virus spreads is not yet fully understood, but it seems to spread and infect people fairly easily. Some people who have been infected in an area may not be sure how or where they were infected. The virus may be 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, such as a handle or object, and then touch your eyes, nose, or mouth. 

For the latest information, visit the CDC website at Or call 800-CDC-INFO (800-232-4636).

What are the symptoms of COVID-19?

Some people have no symptoms or mild symptoms. Symptoms can also vary from person to person. As experts learn more about COVID-19, other symptoms are being reported. Symptoms may appear 2 to 14 days after contact with the virus: 

  • Fever or chills
  • Coughing
  • Trouble breathing or feeling short of breath
  • Sore throat
  • Stuffy or runny nose
  • Headache and body aches
  • Fatigue
  • Nausea, vomiting, diarrhea, or abdominal pain
  • New loss of sense of smell or taste

You can check your symptoms with the CDC’s Coronavirus Self-Checker

What are possible complications from COVID-19?

In many cases, this virus can cause infection (pneumonia) in both lungs. In some cases, this can cause death. Certain people are at higher risk for complications. This includes older adults and people with serious chronic health conditions such as heart or lung disease, diabetes, or kidney disease. It includes people with health conditions that suppress the immune system. And it includes people taking medicines that suppress the immune system. 

As experts learn more about COVID-19, other complications are being reported that may be linked to COVID-19. Rarely, some children have developed severe complications called multisystem inflammatory syndrome in children (MIS-C). MIS-C seems to be similar to Kawaski disease, a rare condition causing inflammation of blood vessels and body organs. It's not yet known if MIS-C happens only in children, or if adults are also at risk. It's also not known if it's related to COVID-19, because many children, but not all, have tested positive for the virus. Experts continue to study MIS-C. The CDC advises healthcare providers to report to local health departments any person under age 21 years old who is ill enough to be in the hospital and has all of the following: 

  • A fever over 100.4°F (38.0°C) for more than 24 hours and a positive SARS-CoV-2 test or exposure to the virus in the last 4 weeks 
  • Inflammation in at least 2 organs such as the heart, lungs, or kidneys with lab tests that show inflammation 
  • No other diagnoses besides COVID-19 explain the child's symptoms 

How is COVID-19 diagnosed?

Your healthcare provider will ask about your symptoms. He or she will ask where you live, and about your recent travel, and any contact with sick people. If your healthcare provider thinks you may have COVID-19, he or she will consider whether to test you for COVID-19. This depends on the availability of testing in your area, and how sick you are. Follow all instructions from your healthcare provider. Guidelines for testing may change as more information about the virus becomes available. Diagnostic tests are used to find a current COVID-19 infection. These include: 

  • Viral (molecular) test. You may also hear this called a RT-PCR test. Viral tests are very accurate. A viral test looks for the SARS-CoV-2 virus's genetic material. A viral test can also detect COVID-19 variants. There are a few ways to do this. A nose-throat swab may be wiped inside your nose to the very back of your throat. Other tests are either done by nose or throat swab. Or a sample of your saliva may be taken. Availability of tests vary by location. Some test kits can be done at home but must be sent to a lab to be checked. Depending on the test, some results are back within about 30 minutes. Some tests must be sent to a lab and can take several days before the results are back. Home test kits are now available but vary by location, and some need a prescription. If you use a home kit, follow the instructions in the kit closely. Some kits get 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. This is done by a nose or a nose-throat swab. Depending on the test, some results are back within an hour. Positive results are highly accurate, but false positives can happen, especially in places where few 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, your healthcare provider may order a viral test. 

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

  • Antibody blood test. Antibody tests are being looked at to find out if a person has previously been infected with the virus and may now have antibodies such as SARS AB IgG in their blood to give some immunity. The accuracy and availability of antibody tests vary. An antibody test may not be able to show if you have a current infection because it can take up to a few weeks after infection to make antibodies. It's not yet known how long immunity lasts after being infected with the virus. 
  • Sputum culture. A small sample of mucus coughed from your lungs (sputum) may be collected if you have a moist cough. It may be checked for the virus or to look for pneumonia. 
  • Imaging tests. You may have a chest X-ray or CT scan. 

Note about reinfection and your immunity

At this time, it's unclear if people can be reinfected with COVID-19. The CDC notes that if a person has fully recovered from COVID-19 and is retested within 3 months of the first infection, they may continue to have low levels of the virus in their body and test positive for COVID-19, even though they are not spreading COVID-19. Having a positive COVID-19 test after an infection doesn't mean you can't be reinfected. It's not yet known how long immunity lasts after being infected with the virus. 

[Download HealthSheet: Understanding Coronavirus Disease 2019 (COVID-19)].

How is COVID-19 treated?

The FDA has approved a vaccine to prevent COVID-19 in people older than 18 (one vaccine has been approved for people as young as 16). Pregnant or breastfeeding people may choose to be vaccinated. Expert groups, including ACOG and the CDC, advise pregnant or breastfeeding people to talk with their healthcare provider about the vaccine.

The vaccine are being rolled out to the public in phases. Check your local health department for your community's roll-out plans. The vaccines are given as a shot (injection) in the arm muscle. A 1-dose or 2-dose vaccine may be given. If you get the 2-dose vaccine, the second dose is given several weeks after the first. Getting the COVID-19 vaccine is important to help prevent the spread of COVID-19 and its variants.

The most proven treatments right now are those to help your body while it fights the virus. This is known as supportive care. For serious COVID-19, you may need to stay in the hospital. Supportive care may include:

  • Getting rest. This helps your body fight the illness. 
  • Staying hydrated. Drinking liquids is the best way to prevent dehydration. Try to drink 6 to 8 glasses of liquids every day, or as advised by your provider. Also check with your provider about which fluids are best for you. Don't drink fluids that contain caffeine or alcohol. 
  • Taking over-the-counter (OTC) pain medicine. These are used to help ease pain and reduce fever. Follow your healthcare provider's instructions for which OTC medicine to use. 

For severe illness, you may need to stay in the hospital. Care during severe illness may include: 

  • IV (intravenous) fluids. These are given through a vein to help keep your body hydrated. 
  • Oxygen. You may be given supplemental oxygen or ventilation with a breathing machine (ventilator). This is done so you get enough oxygen in your body. 
  • Prone positioning. Depending on how sick you are during your hospital stay, your healthcare team may turn you regularly on your stomach. This is called prone positioning. It helps increase the amount of oxygen you get to your lungs. Follow your healthcare team's instructions on position changes while you're in the hospital. Also follow their discharge advice on the best positions to help your breathing once you go home. 
  • Remdesivir. The FDA has approved an IV (intravenous) antiviral medicine called remdesivir. It works by stopping the spread of the SARS-CoV-2 virus in the body. It's approved for people in the hospital. It's for people 12 years and older who weigh more than about 88 pounds (40 kgs). Remdesivir is approved only for people who need to be treated in the hospital. In certain cases, it may also be used for people younger than 12 years or who weigh less than about 88 pounds (40 kgs). Remdesivir is approved only for people who need to be treated in the hospital. In certain cases, it may also be used for people younger than 12 years or who weigh less than about 88 pounds (40 kgs).

Research continues on other therapies that are still experimental. These include: 

  • COVID-19 convalescent plasma. People who have had COVID-19 and are fully recovered may be asked by their healthcare team to consider donating plasma. This is called COVID-19 convalescent plasma donation. Plasma from people fully recovered from COVID-19 may contain antibodies to help fight COVID-19 in people who are currently seriously ill with the disease. Experts don't know if the donated plasma will work well as a treatment. Research continues, and the FDA has approved it for emergency use in certain people with serious or life-threatening COVID-19. Talk with your provider to learn more about convalescent plasma donation and whether you qualify to donate. 
  • Monoclonal antibody therapy. The FDA recently approved this experimental therapy for emergency use for certain people who have a positive COVID-19 viral test and have mild to moderate symptoms but are not in the hospital. It's not widely available and is still being investigated. It's approved for people 12 years and older who weigh about 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 certain chronic conditions. Monoclonal antibody therapy is not approved for people who:
    • Are in the hospital with COVID-19, or
    • Need oxygen therapy for COVID-19, or
    • Need oxygen therapy for a chronic condition and need to have their oxygen flow rate increased because of COVID-19.

Are you at risk for COVID-19?

You are at risk for COVID-19 if you have had close contact with someone with the virus, or if you live in or traveled to an area with cases of it. Close contact means being within 6 feet of a person known to have COVID-19 for a total of 15 minutes or more. This could be multiple short encounters that add up to at least 15 minutes over a 24-hour period. Recent studies suggest that COVID-19 may be spread by people who are not showing symptoms. 

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Last updated: April 5, 2021

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