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What is coronavirus?

Mike Bohl, MD, MPH, ALMchimene richa

Reviewed by Mike Bohl, MD, MPH, ALM, written by Chimene Richa, MD

Last updated: Nov 03, 2021
4 min read


Information about the novel coronavirus (the virus that causes COVID-19) is constantly evolving. We will refresh our novel coronavirus content periodically based on newly published peer-reviewed findings to which we have access. For the most reliable and up-to-date information, please visit the CDC website or the WHO’s advice for the public.

Since it first appeared in the winter of 2019, the coronavirus has spread to nearly every country in the world. Cases have decimated hospital systems and researchers are learning more and more everyday about the virus, the disease it causes, and its long-lasting effects. 

In most people who are infected, the novel coronavirus causes a mild illness or no symptoms at all. Some people do develop more serious illness that can result in death. The disease is called coronavirus disease 2019 or COVID-19—“CO” for corona, “VI” for virus, “D” for disease, and “2019” because of the year it was discovered (CDC, 2020-a). The new strain of coronavirus was present in animals, but in 2019 it was first discovered to be infecting 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 the virus that caused the SARS epidemic in 2002, but it’s not the same virus (CDC, 2020-a).


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How is coronavirus transmitted?

According to the Centers for Disease Control and Prevention (CDC), the virus that causes COVID-19 is transmitted from person to person, mostly through virus-containing respiratory 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). That’s why wearing even simple cloth masks and maintaining distance from other people reduces the chance of viral spread. Research has shown that you’re less likely to contract COVID from touching a contaminated surface like a doorknob and then touching your mouth or nose. 

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 never need special medical treatment and they recover without any complications. According to the World Health Organization (WHO), approximately one in six people with COVID-19 has more severe symptoms. This is most likely to occur in older people and those with other medical problems like heart conditions, diabetes, cancer, or a weak immune system (WHO, 2020). The main symptoms, which can appear anywhere from 2–14 days after infection, include (CDC, 2021-b):

  • Fever
  • Chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Muscle or body aches
  • Headache
  • Sore throat
  • Loss of taste or smell
  • Congestion or runny nose
  • Nausea
  • Vomiting
  • Diarrhea

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 (CDC, 2021-c):

  • If you are sick, stay home (unless you need urgent medical care).
  • Avoid close contact with people who are unvaccinated and are not part of your household.
  • Cover your mouth with a tissue when you sneeze or cough and then throw it away. If you don’t have a tissue, 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.
  • 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.
  • 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.

In addition, the CDC recommends that people wear masks or cloth face coverings in public settings where social distancing is difficult. Cloth face coverings help prevent you from getting others sick, in case you happen to be carrying the virus.

While most people who get coronavirus never require medical attention, a small subset of patients may need treatment. For the most part, treatment is supportive and may include practices like mechanical ventilation, which is when a machine breathes for you. In October of 2020, the FDA (Food and Drug Administration) approved the first treatment for COVID: an antiviral medication called remdesivir (FDA, 2020). In one trial, researchers saw that it improved symptoms and shortened hospital stays in comparison with placebo for patients hospitalized with coronavirus (Beigel, 2020). Other treatments are also being explored. 

Vaccines that prevent the coronavirus are widely available, and it’s important to get vaccinated if you can. Contact your local pharmacy to find out how you can get a COVID-19 vaccine. Getting vaccinated is an effective way to prevent serious coronavirus infections, both for you and those around you.

What we know

Scientists—and everyone else—are still learning about COVID-19. The best thing you can do for yourself is to get vaccinated and practice healthy hygiene practices, like frequent handwashing, avoiding people who are sick, and staying home if you develop symptoms or are exposed to someone who has tested positive. 


  1. Beigel, J. H., Tomashek, K. M., Dodd, L. E., Mehta, A. K., Zingman, B. S., Kalil, A. C., et al. (2020). Remdesivir for the Treatment of Covid-19 – Final Report. The New England Journal of Medicine, 383(19), 1813–1826. doi: 10.1056/NEJMoa2007764. Retrieved from 
  2. Centers for Disease Control and Prevention (CDC). (8 September 2021-a). Coronavirus Disease 2019 (COVID-19) Frequently Asked Questions. Retrieved on Sept. 9, 2021 from
  3. Centers for Disease Control and Prevention. (22 February 2021-b ). Symptoms of Coronavirus. Retrieved on Sept. 9, 2021 from
  4. Centers for Disease Control and Prevention. (13 August 2021-c ). How to Protect Yourself and Others. Retrieved on Sept. 9, 2021 from
  5. Centers for Disease Control and Prevention (CDC). (n.d.). COVID Data Tracker. Retrieved on Sept. 9, 2021 from
  6. FDA: Office of the Commissioner. (Oct 27, 2020). FDA Approves First Treatment for COVID-19. Retrieved on Oct. 27, 2020 from
  7. Onder, G., Rezza, G., & Brusaferro, S. (2020). Case-Fatality Rate and Characteristics of Patients Dying in Relation to COVID-19 in Italy. JAMA, 323(18):1775–1776. doi: 10.1001/jama.2020.4683. Retrieved from  
  8. World Health Organization (WHO) – Coronavirus. (2020). Retrieved on March 2, 2020 from

Dr. Mike is a licensed physician and the Director, Medical Content & Education at Ro.