Overview

Coronaviruses are a family of viruses that can cause illnesses such as the common cold, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). In 2019, a new coronavirus was identified as the cause of a disease outbreak that originated in China.

The virus is now known as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The disease it causes is called coronavirus disease 2019 (COVID-19). In March 2020, the World Health Organization (WHO) declared the COVID-19 outbreak a pandemic.

Public health groups, including the U.S. Centers for Disease Control and Prevention (CDC) and WHO, are monitoring the pandemic and posting updates on their websites. These groups have also issued recommendations for preventing and treating the illness.

Symptoms

Signs and symptoms of coronavirus disease 2019 (COVID-19) may appear two to 14 days after exposure. This time after exposure and before having symptoms is called the incubation period. Common signs and symptoms can include:

• Fever
• Cough
• Tiredness

Early symptoms of COVID-19 may include a loss of taste or smell.
Other symptoms can include:

• Shortness of breath or difficulty breathing
• Muscle aches
• Chills
• Sore throat
• Runny nose
• Headache
• Chest pain
• Pink eye (conjunctivitis)
• Nausea
• Vomiting
• Diarrhea
• Rash

Causes

Infection with the new coronavirus (severe acute respiratory syndrome coronavirus 2, or SARS-CoV-2) causes coronavirus disease 2019 (COVID-19).

The virus that causes COVID-19 spreads easily among people, and more continues to be discovered over time about how it spreads. Data has shown that it spreads mainly from person to person among those in close contact (within about 6 feet, or 2 meters). The virus spreads by respiratory droplets released when someone with the virus coughs, sneezes, breathes, sings or talks. These droplets can be inhaled or land in the mouth, nose or eyes of a person nearby.

In some situations, the COVID-19 virus can spread by a person being exposed to small droplets or aerosols that stay in the air for several minutes or hours — called airborne transmission. It's not yet known how common it is for the virus to spread this way.

It can also spread if a person touches a surface or object with the virus on it and then touches his or her mouth, nose or eyes, but the risk is low.

Some reinfections of the virus that causes COVID-19 have happened, but these have been uncommon.

Prevention

The U.S. Food and Drug Administration (FDA) has given emergency use authorization to some COVID-19 vaccines in the U.S. A vaccine might prevent you from getting COVID-19 or prevent you from becoming seriously ill from COVID-19 if you get the COVID-19 virus.

You can take additional steps to reduce your risk of infection. WHO and CDC recommend following these precautions for avoiding exposure to the virus that causes COVID-19:

• Avoid close contact (within about 6 feet, or 2 meters) with anyone who is sick or has symptoms.
• Keep distance between yourself and others (within about 6 feet, or 2 meters). This is especially important if you have a higher risk of serious illness. Keep in mind some people may have COVID-19 and spread it to others, even if they don't have symptoms or don't know they have COVID-19.
• Avoid crowds and indoor places that have poor ventilation.
• Avoid touching your eyes, nose and mouth.
• Wash your hands often with soap and water for at least 20 seconds, or use an alcohol-based hand sanitizer that contains at least 60% alcohol.
• Wear a face mask in indoor public spaces and outdoors where there is a high risk of COVID-19 transmission, such as at a crowded event. Further mask guidance differs depending on whether you are fully vaccinated or unvaccinated. Surgical masks may be used if available. N95 respirators should be reserved for health care providers.
• Cover your mouth and nose with your elbow or a tissue when you cough or sneeze. Throw away the used tissue. Wash your hands right away.
• Avoid sharing dishes, glasses, towels, bedding and other household items if you're sick.
• Clean and disinfect high-touch surfaces, such as doorknobs, light switches, electronics and counters, daily.
• Stay home from work, school and public areas if you're sick, unless you're going to get medical care. Avoid public transportation, taxis and ride-sharing if you're sick.

If you have a chronic medical condition and may have a higher risk of serious illness, check with your doctor about other ways to protect yourself.