Background and Symptoms of COVID-19

What We Know

COVID-19 is a respiratory disease caused by SARS-CoV-2, a coronavirus discovered in 2019 that had not previously been seen in humans. 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 primarily respiratory and include fever, cough, and shortness of breath. Reported illnesses have ranged from mild to severe and some have resulted in death. Some people with COVID-19 may not have any symptoms but can still spread the virus to others.  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.

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


In addition to basic health and hygienic practices like handwashing, prevention actions for COVID-19 include:

  • vaccination
  • improving ventilation
  • getting tested if needed
  • following recommendations for what to do if you have been exposed
  • staying home when sick
  • seeking treatment if sick and at high risk of severe illness
  • avoiding contact with people who have COVID-19”

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