Background and Symptoms of COVID-19

What We Know

COVID-19 is a new disease, caused by a novel (or new) coronavirus that has not previously been seen in humans. Because it is a new virus, scientists are learning more each day. Although most people who have COVID-19 have mild symptoms, COVID-19 can also cause severe illness and even death. Some groups, including older adults and people who have certain underlying medical conditions, are at increased risk of severe illness.


COVID-19 symptoms are respiratory and include fever, cough, and shortness of breath. Reported illnesses have ranged from mild to severe and some have resulted in death. The virus is spread through respiratory droplets an infected person expels when coughing, sneezing, or talking. The incubation period from time of exposure to onset of symptoms is 2-14 days.

National Jewish Health: Allergies, Cold, Flu, or COVID-19?(PDF, 389KB)

People with these symptoms may have COVID-19:

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Muscle or body aches
  • Headaches
  • New loss of taste or smell
  • Sore throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea


Prevention includes basic infection control precautions such as practicing proper hand washing, covering coughs, avoiding touching one’s mouth, nose or eyes, staying home when ill, disinfecting frequently touched objects and surfaces, and vaccination.

CDC recommends unvaccinated people wear cloth face coverings in public settings where other social distancing measures are difficult to maintain (e.g., grocery stores and pharmacies).

Vaccination against COVID-19 is ongoing, and is one of the best tools available to get us back to a more normal life. Still, it is important to practice the other prevention methods until the vaccine is widely available and used. For more information about COVID-19 vaccine, please visit the COVID-19 Vaccines webpage.

For more prevention tips, please visit the COVID-19 Prevention and Preparedness webpage.