COVID-19, the disease caused by coronavirus, begins with droplets from an infected person's cough, sneeze, or breath. They may be in the air or on a surface you touch before you touch your eyes, nose, or mouth. This causes the virus to pass to the mucous membranes of the throat. Because COVID-19 is transmitted through contact with respiratory fluids that carry the infectious SARS-CoV-2 virus, an infected person can be exposed by coughing or talking near them.
They can also be exposed by inhaling aerosol particles that spread away from the infected person. Airborne transmission of COVID-19 can occur over distances greater than six feet. Particles from an infected person can move around an entire room or interior space. Particles can also remain in the air after a person has left the room; in some cases, they can stay in the air for hours.
A person can also be exposed through splashes and sprays of respiratory fluids directly onto the mucous membranes. Spread can also sometimes occur through contact with contaminated surfaces, although this pathway is now considered to be less likely. See Scientific and Technical Resources Related to indoor air and Coronavirus (COVID-19) or Key Indoor Air and COVID-19 References and Publications for technical information. COVID-19 is transmitted when people breathe in air contaminated by airborne droplets and small particles that contain the virus.
The risk of inhaling them is higher when people are very close, but they can be inhaled over longer distances, especially indoors. Transmission can also occur if contaminated liquids are sprayed or sprayed into the eyes, nose, or mouth and, in rare cases, through contaminated surfaces. People are still contagious for up to 20 days and can spread the virus even if they don't have symptoms.