Microscopic Rendering of Coronavirus
Coronavirus disease 2019 (COVID-19) is a virus (more specifically, a coronavirus) identified as the cause of an outbreak of respiratory illness first detected in Wuhan, China.


What is coronavirus?

Coronaviruses are a family of viruses that can cause respiratory illness in humans. They get their name, “corona,” from the many crown-like spikes on the surface of the virus. Severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS) and the common cold are examples of coronaviruses that cause illness in humans.

The new strain of coronavirus, COVID-19, was first reported in Wuhan, China in December 2019. The virus has since spread to all continents (except Antarctica).

How many people are infected with COVID-19?

The number of people infected changes daily. Organizations that collect this information, including the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC), are gathering information and continuously learning more about this outbreak. As of this writing (5/21/2020), over 5,000,000 people in the world have been infected. Close to 330,000 people have died. Some 188 countries and territories on all continents (except Antartica) have now reported cases of COVID-19. The U.S. has the highest number of cases, with over 1,500,000 people infected and over 93,000 deaths. Russia has more than 315,000 cases, Brazil has over 290,000, England has more than 250,000, Spain has over 230,000 cases, Italy has over 225,000 cases, France has more than 180,000 cases and Germany has more than 175,000 cases. For the latest statistics, see the World Health Organization's situation reports and references at end of article.

How does the new coronavirus (COVID-19) spread from person to person?

COVID-19 is likely spread the same way other human coronaviruses, like the cold, are spread:

  • When the virus becomes airborne and travels in respiratory droplets when an infected person coughs, sneezes or talks near you (within six feet). This is thought to be the main way COVID-19 is spread.
  • From close contact (touching, shaking hands) with an infected person.
  • By touching surfaces that the virus has landed on, then touching your eyes, mouth, or nose before washing your hands. (Not thought to spread easily by this method.)

COVID-19 enters your body through your mouth, nose or eyes (directly from the airborne droplets or from transfer of the virus from your hands to your face). The virus travels to the back of your nasal passages and mucous membrane in the back of your throat. It attaches to cells there, begins to multiply and moves into lung tissue. From there, the virus can spread to other body tissues.

It's important to know that scientists are seeing cases of COVID-19 in people who were infected by individuals who had COVID-19 but were not yet showing symptoms. This is why many governments are requiring a 14-day isolation period for people returning from areas of outbreak. Governments, health agencies, researchers and healthcare providers are all working together to develop policies and procedures to limit the spread of this virus both globally and from individual to individual.

How long is a person infected with COVID-19 considered contagious?

Researchers are still learning about COVID-19. What IS known is that people infected with COVID-19 can spread the virus to others before experiencing symptoms themselves (while people are still “asymptomatic”). This is why healthcare providers are recommending staying six feet away from others (the distance airborne virus can travel) and wearing a cloth mask when around others, washing your hands often, and staying self-isolated at home if you are feeling ill with symptoms that could be COVID-19 or have a positive test for COVID-19.

How soon after becoming infected with COVID-19 will I develop symptoms?

This so-called “incubation period,” the time between becoming infected and showing symptoms, can range from two to 14 days. The average time before experiencing symptoms is five days. Symptoms can range in severity from very mild to severe. In about 80% of patients, COVID-19 causes only mild symptoms.

Who is most at risk for getting COVID-19?

Persons at greatest risk of contracting COVID-19 are:

  • People who live in or have recently traveled to any area with ongoing active spread.
  • People who have had close contact with a person who has a laboratory-confirmed or a suspected case of the COVID-19 virus.
  • People over age 60 who have pre-existing medical conditions or a weakened immune system.

If I recover from a case of COVID-19, can I be infected again?

The U.S. Centers for Disease Control says that "the immune response to COVID-19 is not yet understood." Because this is a new strain of coronavirus, scientists are still collecting information and research on the virus so it's still too early to know.

Symptoms and Causes

What are the symptoms of the novel coronavirus (COVID-19) infection?

The CDC says you may have COVID-19 if you have these symptoms or combination of symptoms:

  • Cough.
  • Shortness of breath or difficulty breathing.
  • Fever.
  • Chills.
  • Muscle pain.
  • Sore throat.
  • New loss of taste or smell.

Other less commonly reported symptoms include nausea, vomiting or diarrhea. Additional symptoms are possible.

Symptoms may appear between two and 14 days after exposure to the virus. Children have similar, but usually milder, symptoms than adults. Older adults and people who have severe underlying medical conditions like heart or lung disease or diabetes are at higher risk of more serious complication from COVID-19.

Call 911 and get immediate medical attention if you have these warning signs:

  • Trouble breathing.
  • Persistent pain or pressure in your chest.
  • New confusion or inability to arouse (wake up from sleep).
  • Bluish lips or face.

This list does not include all possible symptoms. Contact your healthcare provider if you are concerned you may COVID-19, have other symptoms or have any severe symptoms.

Diagnosis and Tests

How is COVID-19 diagnosed?

COVID-19 is diagnosed with a laboratory test. Your healthcare provider may collect a sample of your saliva or swab your nose or throat to send for testing.

When should I be tested for the coronavirus (COVID-19)?

Call your healthcare provider if you:

  • Feel sick with fever, cough or have difficulty breathing.
  • Have been in close contact with a person known or suspected to have COVID-19.

Your healthcare provider will ask you questions about your symptoms. Your healthcare provider will tell you if you need to be tested for the novel coronavirus, COVID-19 and where to go to be tested.

If I have a positive test for COVID-19, how long should I self-isolate?

According to current CDC recommendations, you should self-isolate for 14 days. However, this decision needs to be made on a case-by-case basis. Please call your healthcare provider. Many factors need to be considered, such as:

  • Severity of your COVID-19 infection.
  • Your age and any existing health conditions.
  • How quickly your symptoms go away.

While at home, ideally self-isolate within separate room of your home if possible to limit interaction with other family members. If you can’t stay 100% isolated in a separate room, stay six feet away from others and wear a cloth mask, wash your hands often/family members wash hands often, and frequently disinfect commonly touched surfaces and shared areas.

Is it possible to test negative for COVID-19 and still be infected with the virus?

Yes. This is possible. There are several reasons for “false negative” test results -- meaning you really DO have COVID-19 although the test result says you don’t.

Reasons for a false negative COVID-19 test result include:

  • You were tested too early in the course of illness. The virus hasn’t multiplied in your body to the level that it could be detected by the test.
  • A good specimen was not obtained. The healthcare personnel may not have swabbed deeply enough in the nasal cavity to collect a good sample. There could also be handling errors and transportation errors, as the sample must be transported to a lab to be tested.
  • The COVID-19 test itself was not sensitive or specific enough to detect COVID-19. “Sensitivity” refers to the ability of the test to detect the smallest amount of virus. “Specificity” refers to the ability of the test to detect only the COVID-19 virus and not other similar viruses. Many different commercial and hospital laboratories have developed tests for COVID-19. All must meet standards, but no test is 100% sensitive and 100% specific for COVID-19. This is why there is always a possibility of “false negative” and “false positive” tests.

If you think you might have COVID-19 even if your test is negative, it’s best to follow the current CDC recommendation. Stay home for 14 days if you think you are sick. Stay six feet away from others (“social distancing”) and wear a cloth mask. Contact your healthcare provider if your symptoms worsen. Contact your healthcare provider when your symptoms improve – don’t decide on your own if it’s safe for you to be around others.

Management and Treatment

How is COVID-19 treated?

Current ways to manage COVID-19 include using the same support care (e.g., rest, fluids, fever control) and preventive measures used to treat other coronaviruses such as a cold.

At the moment, there is no cure for COVID-19. Scientists are currently developing a vaccine, which has begun being tested in a limited number of people. There are several stages to vaccine testing in humans, each of which takes many months to complete. Scientists first make sure the vaccine is safe, then determine the most effective dose before manufacturing can begin. Typical vaccine development time is 12 to 18 months, but scientists (all working around the world) are hopeful that this time frame will be shortened.

There are no drugs specifically approved to treat COVID-19. Some drugs already approved in the U.S. for other medical conditions are beginning to be given -- as a trial -- to patients infected with COVID-19. These drugs include hydroxycholoroquine (approved to treat malaria, lupus and arthritis) chloroquine (approved to treat malaria) and the antibiotic azithromycin. The FDA recently granted an emergency use authorization for the investigational antiviral, remdesivir, for hospitalized patients with severe disease. The drug has been shown to shorten the recovery time in some patients.


How can I prevent getting the novel coronavirus (COVID-19)?

Right now, the best defense to prevent getting COVID-19 is to follow some of the same steps you would take to prevent getting other viruses, such as the common cold or the flu.

  • Wash your hands for at least 20 seconds— especially before eating and preparing food, after using the bathroom, after wiping your nose, and after coming in contact with someone who has a cold.
  • Avoid touching your eyes, nose and mouth to prevent the spread of viruses from your hands.
  • Cover your mouth and nose with a tissue when sneezing and coughing or sneeze and cough into your sleeve. Throw the tissue in the trash. Wash your hands afterward. Never cough or sneeze into your hands!
  • Avoid close contact (within 6 feet) with those who have coughs, colds or are sick. Stay home if you are sick.
  • If you are prone to sickness or have a weakened immune system, stay away from large crowds of people. Follow the directions of your healthcare authorities especially during outbreaks.
  • Clean frequently used surfaces (such as doorknobs and counter tops) with a virus-killing disinfectant.
  • Use hand sanitizers that contain at least 60% alcohol if soap and water are not available.
  • Greet people with a friendly gesture instead of shaking hands.
  • Get enough sleep, eat a healthy diet, drink plenty of liquids and exercise if you are able. These steps will strengthen your immune system and enable you to fight off infections easier.

Should I wear a face mask?

The CDC recommends wearing a cloth face coverings in public, especially in places where it’s hard to maintain at least six feet of distance between yourself and another person. Cloth face masks are being recommended because we now know individuals with COVID-19 could have mild or no symptoms, while still spreading the virus to others.

The cloth face coverings recommended by the CDC are not surgical masks or N-95 respirators, which should be reserved for healthcare workers and first responders.

How deadly is COVID-19?

So far, health officials are seeing mostly mild to moderate infections caused by the novel coronavirus, COVID-19. The death rate from COVID-19 compared with other coronavirus outbreaks remains low at this point in time. The death rate from the SARS outbreak was about 10% of the about 8,000 people who were infected with this virus worldwide. The death rate from the MERS outbreak was about 35% in the nearly 2,500 reported cases. So far, the death rate from the COVID-19 virus about 3%. However, this can change. Scientists are still continuing to learn about this virus including how it’s spreading, how quickly it’s spreading, how severe an illness it’s causing and how it might be treated.


Where can I learn more about COVID-19?

Additional Information

Where do coronaviruses come from?

Coronaviruses are often found in bats, cats and camels. The viruses live in but do not infect the animals. Sometimes these viruses then spread to different animal species. The viruses may change (mutate) as they transfer to other species. Eventually, the virus can jump from animal species and begins to infect humans. In the case of COVID-19, the first people infected in Wuhan, China are thought to have contracted the virus at a food market that sold meat, fish and live animals. Although researchers don’t know exactly how people were infected, they already have evidence that the virus can be spread directly from person to person through close contact.

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