Coronaviruses are a type of virus that can cause illnesses like the common cold, SARS, and Middle East respiratory syndrome (MERS). In 2019, a new coronavirus was discovered to be the source of a disease outbreak in China.

The virus is now known as coronavirus 2 (severe acute respiratory syndrome) (SARS-CoV-2). Coronavirus disease 2019 is the name of the disease it causes (COVID-19). The World Health Organization (WHO) proclaimed the COVID-19 outbreak a pandemic in March 2020.

The Centers for Disease Control and Prevention (CDC) in the United States and the World Health Organization (WHO) are keeping tabs on the pandemic and providing information on their websites. These organizations have also provided prevention and treatment guidelines.


Two to 14 days after exposure, signs and symptoms of coronavirus disease 2019 (COVID-19) may appear. The incubation period is the interval between exposure and onset of symptoms. The following are some of the most common signs and symptoms:

  1. Fever
  2. Cough
  3. Tiredness
  4. Early symptoms of COVID-19 may include a loss of taste or smell.

Other symptoms can include:

  1. Shortness of breath or difficulty breathing
  2. Muscle aches
  3. Chills
  4. Sore throat
  5. Runny nose
  6. Headache
  7. Chest pain
  8. Vomiting
  9. Diarrhea

This is not an exhaustive list. Children’s symptoms are identical to adults’, although they usually have a mild disease.

COVID-19 symptoms can vary in severity from mild to severe. Some people may only have a few symptoms, and others may have none at all. About a week after symptoms begin, some people can experience worsening symptoms, such as shortness of breath and pneumonia.COVID-19 poses a greater risk of serious illness in the elderly, and the risk rises with age. People with pre-existing medical conditions may be more susceptible to severe illness. The following medical conditions can increase the risk of COVID-19-related serious illness:

  1. Cancer
  2. Chronic obstructive pulmonary disease (COPD)
  3. Type 1 or type 2 diabetes
  4. Overweight, obesity or severe obesity
  5. High blood pressure
  6. Smoking
  7. Chronic kidney disease
  8. Sickle cell disease or thalassemia
  9. Pregnancy
  10. Asthma
  11. Chronic lung diseases such as cystic fibrosis or pulmonary fibrosis
  12. Liver disease
  13. Dementia
  14. Down syndrome
  15. Weakened immune system from bone marrow transplant, HIV or some medications


Coronavirus disease is caused by infection with the new coronavirus (severe acute respiratory syndrome coronavirus 2, or SARS-CoV-2) (COVID-19).

COVID-19 is caused by a virus that spreads easily among people, and more information on how it spreads is being discovered all the time. According to data, it primarily spreads from person to person among those in close proximity (within about 6 feet, or 2 meters). When a person with the virus coughs, sneezes, breathes, sings, or speaks, respiratory droplets are released. These droplets may be inhaled or land in someone’s mouth, nose, or eyes.

When a person is exposed to tiny droplets or aerosols that remain in the air for several minutes or hours, the COVID-19 virus will spread. This is known as airborne transmission. It’s unclear how widespread this method of virus transmission is.

It can also spread if a person comes into contact with a virus-infected surface or object and then touches his or her mouth, nose, or eyes, but the risk is minimal.

When to consult a doctor

If you have COVID-19 signs or symptoms, or if you’ve come into touch with someone who has been diagnosed with COVID-19, seek medical help right away. Before you go to your appointment, tell your doctor about your symptoms and any potential exposure.

Seek medical attention right away if you have COVID-19 emergency signs and symptoms. The following are examples of emergency signs and symptoms:

  1. Trouble breathing
  2. Persistent chest pain or pressure
  3. Inability to stay awake
  4. New confusion
  5. Pale, gray or blue-colored skin, lips or nail beds — depending on skin tone

Risk Factors

  1. Near proximity to anyone who has COVID-19 (within 6 feet, or 2 meters)
  2. An infected person coughing or sneezing on you


Some COVID-19 vaccines have been granted emergency use authorization by the US Food and Drug Administration (FDA). A vaccine can help you avoid contracting COVID-19 or preventing you from becoming seriously ill from it if you do contract it.

You should take extra precautions to lower the infection risk. The World Health Organization and the Centers for Disease Control and Prevention recommend taking the following steps to stop contracting COVID-19:

  1. Wash your hands often with soap and water for at least 20 seconds, or use a hand sanitizer containing at least 60% alcohol.
  2. Use a face mask in indoor and outdoor public spaces where COVID-19 transmission is a high risk, such as at a crowded case. If you are completely vaccinated or unvaccinated, you would need to follow different mask instructions. If surgical masks are available, they can be used. N95 respirators can only be used by medical personnel.
  3. When you cough or sneeze, cover your mouth and nose with your forearm or a tissue. Discard the discarded tissue.
  4. Hands should be washed as soon as possible.
  5. Keep your hands away from your eyes, nose, and mouth.
  6. Avoid being in near proximity to someone who is ill or has symptoms (within 6 feet, or 2 meters). 
  7. Maintain a safe distance from others (within about 6 feet, or 2 meters). If you have a higher risk of serious illness, this is particularly necessary. Keep in mind that even though they don’t have symptoms or are unaware that they have COVID-19, some people will spread it to others. 
  8. Stay away from crowded areas and locations with low ventilation.
  9. If you’re sick, don’t share plates, cups, blankets, bedding, or other household things. 
  10. Wipe down high-touch surfaces like doorknobs, light switches, phones, and counters on a regular basis. 
  11. If you’re sick, stay home from work, school, and public places unless you’re going to see a doctor. If you’re sick, stay away from public transit, taxis, and ride-sharing services.


Coronavirus disease 2019 (COVID-2019). Centers for Disease Control and Prevention. Accessed April 28, 2021.
Coronavirus disease (COVID-19) outbreak. World Health Organization. Accessed April 17, 2020.
AskMayoExpert. COVID-19. Mayo Clinic; 2020.
AskMayoExpert. Upper respiratory tract infection. Mayo Clinic; 2020.
Tosh PK (expert opinion). Mayo Clinic. March 16, 2020.