The Covid-19 coronavirus outbreak is a new illness and scientists are still assessing how it spreads from person to person, but similar viruses tend to spread via cough and sneeze droplets.
When an infected person coughs or sneezes, they release droplets of saliva or mucus. These droplets can fall on people in the vicinity and can be either directly inhaled or picked up on the hands then transferred when someone touches their face, causing infection. For flu, some hospital guidelines define exposure as being within six feet of an infected person who sneezes or coughs for 10 minutes or longer.
Viruses can also be spread through droplets landing on surfaces such as seats on buses or trains or desks in school. However, whether this is a main transmission route depends on how long viruses survive on surfaces – this can vary from hours to months.
There is anecdotal evidence that the virus can be spread by people before they have symptoms. Some other illnesses such as flu can be passed from one person to another before symptoms occur – but the extent to which this is happening with the new coronavirus is not well understood yet.
How to protect yourself and others
Wash your hands: wet your hands with clean, running water and apply soap. Lather your hands, including the backs, between your fingers, and under your nails and scrub for at least 20 seconds. Rinse.
Cover your mouth and nose with a tissue when you cough or sneeze, then throw the tissue in the bin and wash your hands. If you do not have a tissue to hand, cough or sneeze into your elbow rather than your hands.
Face masks offer some protection as they block liquid droplets. However, they do not block smaller aerosol particles that can pass through the material of the mask. The masks also leave the eyes exposed and there is evidence that some viruses can infect a person through the eyes.
Seek early medical help if you have a fever, cough and difficulty breathing, and share your travel history with healthcare providers.
If visiting live markets in affected areas avoid direct, unprotected contact with live animals and surfaces that have been in contact with animals.
If you have returned from an affected area in the last two weeks, stay indoors and avoid contact with other people for 14 days. This means not going to work, school or public areas.
If you have returned from an infected area and develop a high temperature, cough, runny nose, sore throat or difficulty breathing do not leave your home until you have been given advice by a doctor.