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Last updated April 2, 2020. 6 minute read

Understanding what COVID-19 is

Dr Chimene Richa Md Written by Dr. Chimene Richa, MD
Reviewed by Dr. Tzvi Doron, DO


  • Coronaviruses are a family of viruses that cause a range of respiratory illnesses, including the common cold, Middle East respiratory syndrome (MERS), and severe acute respiratory syndrome (SARS).
  • The newest strain of coronavirus, which causes coronavirus disease 2019 (COVID-19), was recently discovered in humans. It started in Wuhan, China and has spread globally.
  • COVID-19 is characterized by symptoms that are similar to the common cold and flu, such as fever, cough, and shortness of breath.
  • 80% of people who get COVID-19 recover without needing special treatment. Approximately one in six people (especially those who are older or have other medical issues) will get more severe symptoms, and the risk of death from COVID-19 in infected people is currently estimated to be 3.4%. However, other estimates suggest the case fatality rate is closer to 1%.
  • The best treatment is prevention by avoiding people who are sick, staying home if you are sick, and washing hands with soap and water for 20 seconds regularly.

Coronaviruses are a family of viruses that cause a range of respiratory illnesses. Under a microscope, viruses in this family have an outer crown or “corona.” If you have ever had the common cold, you likely have had a coronavirus infection. Several coronaviruses affect humans, and they cause different illnesses. Some cause a mild illness like the common cold, while others cause more severe conditions, like Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS). The novel coronavirus that everyone has been talking about lately usually causes a mild illness (WHO, 2020), but it can have more severe symptoms in some people. The disease is called coronavirus disease 2019 or COVID-19—“COVI” for coronavirus, “D” for disease, and “2019” because of the year it was discovered (CDC, 2020). The new strain of coronavirus was present in animals, but in 2019 it was first discovered to be affecting humans in Wuhan, China. The virus that causes COVID-19 is called severe acute respiratory syndrome coronavirus 2, which is shortened to SARS-CoV-2. It is related to SARS but is not the same virus (CDC, 2020).

What is COVID-19?

COVID-19 is the disease caused by the new coronavirus called SARS-CoV-2. This virus started out as a virus that infects bats. At some point, the virus changed, and it gained the ability to infect humans. Reports of the virus causing a new illness in humans first came out of Wuhan, Hubei Province, China. At first, most of the infected people had had contact with live animals at a large market prior to the infection, suggesting that the virus was jumping from animals to people. Later on, it became clear that the virus was also moving from person-to-person, as more people without animal contact were getting infected. Since international travel is relatively accessible, the illness has now spread outside of China to the rest of the world. You can click here to see the latest numbers for COVID-19 in the United States (CDC, 2020).

According to the Centers for Disease Control and Prevention (CDC), the virus that causes COVID-19 is transmitted mainly from person-to-person, mostly through virus-infected droplets that are produced when an infected person coughs or sneezes. These droplets can travel approximately six feet. If one of these infected droplets lands in a person’s mouth or nose, they may get infected. This is why it is recommended that you stay at least six feet away from someone who is sick and coughing (WHO, 2020). 

It is possible that if you touch an infected object like a doorknob or other infected surface and then touch your mouth or nose, you could get COVID-19. However, person-to-person contact is generally thought to be the most common method of virus spread. What about products shipped from infected countries like China? According to the CDC, it is not likely that coronavirus can survive on product or package surfaces, especially if they are shipped over a period of days to weeks (CDC, 2020). At this time, there are no reported cases of someone in the U.S. getting COVID-19 because of a package shipped from another country and no evidence to suggest that this is a concerning possibility (CDC, 2020).

Scientists believe that people are the most contagious when they are the sickest, but what about catching the virus from someone with no symptoms? The chance of this happening is very low. However, many people with COVID-19 have very mild symptoms (or even none at all), especially in the early days of the disease. Because of this, it is possible to catch the virus from someone who does not appear very ill (WHO, 2020).

Signs and symptoms of COVID-19

The signs and symptoms of COVID-19 can range from mild to severe and even results in death in some cases. More than 80% of people with COVID-19 recover without any complications or needing special treatment. According to the World Health Organization (WHO), approximately one in six people with COVID-19 have more severe symptoms. This is most likely to occur in older people and those with other medical problems like high blood pressure, heart problems, diabetes, cancer, or a weak immune system (WHO, 2020). On March 3, 2020, the Director-General of the WHO, Dr. Tedros Adhanom Ghebreyesus, reported a 3.4% fatality rate from COVID-19. However, the case fatality rate is likely to be dependent on a number of factors and may vary. One study found that, as of February 11, 2020, the case fatality rate in China was 2.3% while, as of March 17, 2020, the case fatality rate in Italy was 7.2% (Onder, 2020). The main symptoms, which can appear anywhere from 1–14 days after infection, include (WHO, 2020):

  • Fever
  • Cough
  • Difficulty breathing/shortness of breath

Additional symptoms, such as fatigue, are also possible. If these look familiar, that is because the common cold and flu viruses can cause similar symptoms. How can you tell the difference? It’s not easy, and you can’t reliably tell the difference based only on symptoms alone. Call your healthcare provider if you have a fever along with a cough or trouble breathing and any of the following (CDC, 2020):

  • You have been in close contact (less than six feet) with someone known to have COVID-19
  • You live in an area with widespread virus transmission (see the CDC’s list of countries here)
  • You have recently traveled to an area with widespread virus transmission (see the CDC’s list of countries here)

Your provider will work with the CDC and local health department to decide if you need to be tested for COVID-19.

Prevention and treatment of COVID-19

The best way to prevent you or your family from getting sick is to use healthy practices that prevent the spread of germs, similar to what you probably already do to avoid catching a cold, the flu, or other respiratory viruses.

  • If you are sick, stay home (unless you need urgent medical care).
  • Avoid close contact (less than six feet) with people who are sick. To help prevent the spread of the disease, practice social distancing, which involves staying at least six feet away from everybody.
  • Cover your mouth with a tissue when you sneeze or cough and then throw it away. If there are no tissues readily available, sneeze, or cough into your elbow rather than your hands. Wash your hands with soap and water afterward.
  • Avoid touching your mouth, nose, or eyes.
  • Clean and disinfect surfaces daily that you touch regularly (like doorknobs, countertops, etc.).
  • Wash your hands with soap and water for at least 20 seconds, especially after going to the bathroom, before eating, and after blowing your nose, coughing, or sneezing. Alternatively, you can use a hand sanitizer that is at least 60% alcohol if soap and water are not available. If your hands are visibly soiled, you should wash them with soap and water. Hand sanitizer is not a good alternative in this case.

Wearing a mask does not prevent you from getting COVID-19. The CDC does not recommend that healthy people wear a facemask to protect themselves from the virus. However, if you have COVID-19 symptoms, wearing a mask can help prevent the virus from spreading to others. If you are taking care of someone with COVID-19 and need to have close contact with them, then a facemask may be indicated—talk with your healthcare provider.

Unfortunately, there is no treatment against the virus that causes COVID-19. Rather, treatment focuses on improving the symptoms. If the symptoms are severe, this may mean hospitalization and even being placed on a respirator. At this point, the best treatment is prevention.

In conclusion

Scientists—and everyone else—are still learning about COVID-19 and how to keep as many people as healthy as possible. The best thing you can do for yourself is use healthy hygiene practices, like frequent hand-washing, avoiding people who are sick, and staying home if you develop symptoms. Keep yourself informed on the status of the virus in your area and review prevention guidelines with your community, friends, and family members.